(1993) Benchmarks for Science Literacy Project 2061. American Association for the Advancement of Science. Oxford University Press.
The Nature of Science
A. The Scientific world view
1. By the end of the 2nd grade, students should know that
a. When a science investigation is done the way it was done before we expect to get a very similar result.
b. Science investigations generally work the same way in different places.
2. By the end of the 5th grade, students should know that
a. Results of similar scientific investigations seldom turn out exactly the same. Sometimes this is because of unexpected differences in the things being investigated, sometimes because of unrealized differences in the methods used or in the circumstances in which the investigation is carried out, and sometimes just because of uncertainties in observations. It is not always easy to tell which.
3. By the end of the 8th grade, students should know that
a. When similar investigations give different results, the scientific challenge is to judge whether the differences are trivial or significant, and it often takes further studies to decide. Even with similar results, scientists may wait until an investigation has been repeated many times before accepting the results as correct.
b. Scientific knowledge is subject to modification as new information challenges prevailing theories and as a new theory leads to looking at old observations in a new way.
c. Some scientific knowledge is very old and yet is still applicable today.
d. Some matters cannot be examined usefully in a scientific way. Among them are matters that by their nature cannot be tested objectively and those that are essentially matters of morality. Science can sometimes be used to inform ethical decisions by identifying the likely consequences of particular actions but cannot be used to establish that some action is either moral or immoral.
B. Scientific Inquiry
1. By the end of the second grade, students should know that
a. People can often learn about things around them by just observing those things carefully, but sometimes they can learn more by doing something to the things and noting what happens.
b. Tools such as thermometers, magnifiers, rulers, or balances often give more information about things than can be obtained by just observing things without their help.
c. Describing things as accurately as possible is important in science because it enables people to compare their observations with those of others.
d. When people give different descriptions of the same thing, it is usually a good idea to make some fresh observations instead of just arguing about who is right.
2. By the end of the 5th grade, students should know that
a. Scientific investigations may take many different forms, including observing what things are like or what is happening somewhere, collecting specimens for analysis, and doing experiments. Investigations can focus on physical, biological, and social questions.
b. Results of scientific investigations are seldom exactly the same, but if the differences are large, it is important to try to figure out why. One reason for following directions carefully and for keeping records of one's work is to provide information on what might have caused the differences.
c. Scientists' explanations about what happens in the world come partly from what they observe, partly from what they think. Sometimes scientists have different explanations for the same set of observations. That usually leads to their making more observations to resolve the differences.
d. Scientists do not pay much attention to claims about how something they know about works unless the claims are backed up with evidence that can be confirmed and with a logical argument.
3. By the end of the 8th grade, students should know that
a. Scientists differ greatly in what phenomena they study and how they go about their work. Although there is no fixed set of steps that all scientists follow, scientific investigations usually involve the collection of relevant evidence, the use of logical reasoning, and the application of imagination in devising hypotheses and explanations to make sense of the collected evidence.
b. If more than one variable changes at the same time in an experiment, the outcome of the experiment may not be clearly attributable to any one of the variables. It may not always be possible to prevent outside variables from influencing the outcome of an investigation (or even to identify all of the variables), but collaboration among investigators can often lead to research designs that are able to deal with such situations.
c. What people expect to observe often affects what they actually do observe. Strong beliefs about what should happen in particular circumstances can prevent them from detecting other results. Scientists know about this danger to objectivity and take steps to try and avoid it when designing investigations and examining data. One safeguard is to have different investigators conduct independent studies of the same questions.
d. New ideas in science sometimes spring from unexpected findings, and they usually lead to new investigations.
C. The scientific enterprise
1. By the end of the 2nd grade, students should know that
a. Everybody can do science and invent things and ideas.
b. In doing science, it is often helpful to work with a team and to share findings with others. All team members should reach their own individual conclusions, however, about what the findings mean.
c. A lot can be learned about plants and animals by observing them closely, but care must be taken to know the needs of living things and how to provide for them in the classroom.
2. By the end of the 5th grade, students should know that
a. Science is an adventure that people everywhere can take part in, as they have for many centuries.
b. Clear communication is an essential part of doing science. It enables scientists to inform others about their work, expose their ideas to criticism by other scientists, and stay informed about scientific discoveries around the world.
c. Doing science involves many different kinds of work and engages men and women of all ages and backgrounds.
3. By the end of the 8th grade, students should know that
a. Important contributions to the advancement of science, mathematics, and technology have been made by different kinds of people, in different cultures, at different times.
b. Until recently, women and racial minorities, because of restrictions on their education and employment opportunities, were essentially left out of much of the formal work of the science establishment; the remarkable few who overcame those obstacles were even then likely to have their work disregarded by the science establishment.
c. No matter who does science and mathematics or invents things, or when or where they do it, the knowledge and technology that result can eventually become available to everyone in the world.
d. Scientists are employed by colleges and universities, business and industry, hospitals, and many government agencies. Their places of work include offices, classrooms, laboratories, farms, factories, and natural field settings ranging from space to the ocean floor.
e. In research involving human subjects, the ethics of science require that potential subjects be fully informed about the risks and benefits associated with the research and of their right to refuse to participate. Science ethics also demand that scientists must not knowingly subject coworkers, students, the neighborhood, or the community to health or property risks without their prior knowledge and consent. Because animals cannot make informed choices, special care must be taken in using them in scientific research.
f. Computers have become invaluable in science because they speed up and extend people's ability to collect, store, compile, and analyze data, prepare research reports, and share data and ideas with investigators all over the world.
g. Accurate record-keeping, openness, and replication are essential for maintaining an investigator's credibility with other scientists and society.
1. By the end of the 2nd grade, students should know that
a. Circles, squares, triangles, and other shapes can be found in things in nature and in things that people build.
b. Patterns can be made by putting different shapes together or taking them apart.
c. Things move, or can be made to move, along straight, curved, circular, back-and-forth, and jagged paths.
2. By the end of the 5th grade, students should know that
a. Mathematics is the study of many kinds of patterns, including numbers and shapes and operations on them. Sometimes patterns are studied because they help to explain how the world works or how to solve practical problems, sometimes because they are interesting in themselves.
b. Mathematical ideas can be represented concretely, graphically, and symbolically.
3. By the end of the 8th grade, students should know that
a. Usually there is no one right way to solve a mathematical problem; different methods have different advantages and disadvantages.
b. Logical connections can be found between different parts of mathematics.
1. By the end of the 8th grade, students should know that
a. Mathematics is helpful in almost every kind of human endeavor--from laying bricks to prescribing medicine or drawing a face. In particular, mathematics has contributed to progress in science and technology for thousands of years and still continues to do so.
1. By the end of the 2nd grade, students should know that
a. Numbers and shapes can be used to tell about things.
2. By the end of the 5th grade, students should know that
a. Numbers and shapes--and operations on them--help to describe and predict things about the world around us.
b. In using mathematics, choices have to be made about what operations will give the best results. Results should always be judged by whether they make sense and are useful.
3. By the end of the 8th grade, students should know that
a. Mathematicians often represent things with abstract ideas, such as numbers or perfectly straight lines, and then work with those ideas alone. The "things" from which they abstract can be ideas themselves (for example, a proposition about "all equal-sided triangles" or "all odd numbers").
b. When mathematicians use logical rules to work with representations of things, the results may or may not be valid for the things themselves. Using mathematics to solve a problem requires choosing what mathematics to use; probably making some simplifying assumptions, estimates, or approximations; doing computations; and then checking to see whether the answer makes sense. If an answer does not seem to make enough sense for its intended purpose, then any of these steps might have been inappropriate.
1. By the end of the 2nd grade, students should know that
a. Tools are used to do things better or more easily and to do some things that could not otherwise be done at all. In technology, tools are used to observe, measure, and make things.
b. When trying to build something or to get something to work better, it usually helps to follow directions if there are any or to ask someone who has done it before for suggestions.
2. By the end of the 5th grade, students should know that
a. Throughout all of history, people everywhere have invented and used tools. Most tools of today are different from those of the past but many are modifications of very ancient tools.
b. Technology enables scientists and others to observe things that are too small or too far away to be seen without them and to study the motion of objects that are moving very rapidly or are hardly moving at all.
c. Measuring instruments can be used to gather accurate information for making scientific comparisons of objects and events and for designing and constructing things that will work properly.
d. Technology extends the ability of people to change the world: to cut, shape, or put together materials; to move things from one place to another; and to reach farther with their hands, voices, senses, and minds. The changes may be for survival needs such as food, shelter, and defense, for communication and transportation, or to gain knowledge and express ideas.
3. By the end of the 8th grade, students should know that
a. In earlier times, the accumulated information and techniques of each generation of workers were taught on the job directly to the next generation workers. Today, the knowledge base for technology can be found as well in libraries of print and electronic resources and is often taught in the classroom.
b. Technology is essential to science for such purposes as access to outer space and other remote locations, sample collection and treatment, measurement, data collection and storage, computation, and communication of information.
c. Engineers, architects, and others who engage in design and technology use scientific knowledge to solve practical problems. But they usually have to take human values and limitations into account as well.
1. By the end of the 2nd grade, students should know that
a. People can use objects and ways of doing things to solve problems.
b. People may not be able to actually make or do everything that they can design.
2. By the end of the 5th grade, students should know that
a. There is no perfect design. Designs that are best in one respect (safety or ease of use, for example) may be inferior in other ways (cost or appearance). Usually some features must be sacrificed to get others. How such trade-offs are received depends upon which features are emphasized and which are down-played.
b. Even a good design may fail. Sometimes steps can be taken ahead of time to reduce the likelihood of failure, but it cannot be entirely eliminated.
c. The solution to one problem may create other problems.
3. By the end of the 8th grade, students should know that
a. Design usually requires taking constraints into account. Some constraints, such as gravity or the properties of the materials to be used, are unavoidable. Other constraints, including economic, political, social, ethical, and aesthetic ones, limit choices.
b. All technologies have effects other than those intended by the design, some of which may have been predictable and some not. In either case, these side effects may turn out to be unacceptable to some of the populations and therefore lead to conflict between groups.
c. Almost all control systems have inputs, outputs, and feedback. The essence of control is comparing information about what is happening to what people want to happen and then making appropriate adjustments. This procedure requires sensing information, processing it, and making changes. In almost all modern machines, microprocessors serve as centers of performance control.
d. Systems fail because they have faulty or poorly matched parts, are used in ways that exceed what was intended by the design, or were poorly designed to begin with. The most common ways to prevent failure are pretesting parts and procedures, overdesign, and redundancy.
1. By the end of the 2nd grade, students should know that
a. People, alone or in groups, are always inventing new ways to solve problems and get work done. The tools and ways of doing things that people have invented affect all aspects of life.
b. When a group of people wants to build something or try something new, they should try to figure out ahead of time how it might affect other people.
2. By the end of the 5th grade, students should know that
a. Technology has been part of life on the earth since the advent of the human species. Like language, ritual, commerce, and the arts, technology is an intrinsic part of human culture, and it both shapes society and is shaped by it. The technology available to people greatly influences what their lives are like.
b. Any invention is likely to lead to other inventions. Once an invention exists, people are likely to think up ways of using it that were never imagined at first.
c. Transportation, communications, nutrition, sanitation, health care, entertainment, and other technologies give large numbers of people today the goods and services that once were luxuries enjoyed only by the wealthy. These benefits are not equally available to everyone.
d. Scientific laws, engineering principles, properties of materials, and construction techniques must be taken into account in designing engineering solutions to problems. Other factors, such as cost, safety, appearance, environmental impact, and what will happen if the solution fails also must be considered.
e. Technologies often have drawbacks as well as benefits. A technology that helps some people or organisms may hurt others--either deliberately (as weapons can) or inadvertently (as pesticides can). When harm occurs or seems likely, choices have to be made or new solutions found.
f. Because of their ability to invent tools and processes, people have an enormous effect on the lives of other living things.
3. By the end of the 8th grade, students should know that
a. The human ability to shape the future comes from a capacity for generating knowledge and developing new technologies--and for communicating ideas to others.
b. Technology cannot always provide successful solutions for problems or fulfill every human need.
c. Throughout history, people have carried out impressive technological feats, some of which would be hard to duplicate today even with modern tools. The purposes served by these achievements have sometimes been practical, sometimes ceremonial.
d. Technology has strongly influenced the course of history and continues to do so. It is largely responsible for the great revolutions in agriculture, manufacturing, sanitation and medicine, warfare, transportation, information processing, and communications that have radically changed how people live.
e. New technologies increase some risks and decrease others. Some of the same technologies that have improved the length and quality of life for many people have also brought new risks.
f. Rarely are technology issues simple and one-sided. Relevant facts alone, even when known and available, usually do not settle matters entirely in favor of one side or another. That is because the contending groups may have different values and priorities. They may stand to gain or lose in different degrees, or may make very different predictions about what the future consequences of the proposed action will be.
g. Societies influence what aspects of technology are developed and how these are used. People control technology (as well as science) and are responsible for its effects.
1. By the end of the 2nd grade, students should know that
a. There are more stars in the sky than anyone can easily count, but they are not scattered evenly, and they are not all the same in brightness or color.
b. The sun can be seen only in the daytime, but the moon can be seen sometimes at night and sometimes during the day. The sun, moon, and stars all appear to move slowly across the sky.
c. The moon looks a little different every day, but looks the same again about every four weeks.
2. By the end of the 5th grade, students should know that
a. The patterns of stars in the sky stay the same, although they appear to move across the sky nightly, and different stars can be seen in different seasons.
b. Telescopes magnify the appearance of some distant objects in the sky, including the moon and the planets. The number of stars that can be seen through telescopes is dramatically greater than can be seen by the unaided eye.
c. Planets change their positions against the background of stars.
d. The earth is one of several planets that orbit the sun, and the moon orbits around the earth.
e. Stars are like the sun, some being smaller and some larger, but so far away that they look like points of light.
3. By the end of the 8th grade, students should know that
a. The sun is a medium-sized star located near the edge of a disk-shaped galaxy of stars, part of which can be seen as a glowing band of light that spans the sky on a very clear night. The universe contains many billions of galaxies, and each galaxy contains many billions of stars. To the naked eye, even the closest of these galaxies is no more than a dim, fuzzy spot.
b. The sun is many thousands of times closer to the earth than any other star. Light from the sun takes a few minutes to reach the earth, but light from the next nearest star takes a few years to arrive. The trip to that star would take the fastest rocket thousands of years. Some distant galaxies are so far away that their light takes several billion years to reach the earth. People on earth, therefore, see them as they were that long ago in the past.
c. Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits. Some planets have a great variety of moons and even flat rings of rock and ice particles orbiting around them. Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris.
d. Large numbers of chunks of rock orbit the sun. Some of those that the earth meets in its yearly orbit around the sun glow and disintegrate from friction as they plunge through the atmosphere--and sometimes impact the ground. Other chunks of rocks mixed with ice have long, off-center orbits that carry them close to the sun, where the sun's radiation (of light and particles) boils off frozen material from their surfaces and pushes it into a long, illuminated tail.
1. By the end of the 2nd grade, students should know that
a. Some events in nature have a repeating pattern. The weather changes some from day to day, but things such as temperature and rain (or snow) tend to be high, low, or medium in the same months every year.
b. Water can be a liquid or a solid and can be made to go back and forth from one form to the other. If water is turned into ice and then the ice is allowed to melt, the amount of water is the same as it was before freezing.
c. Water left in an open container disappears, but water in a closed container does not disappear.
2. By the end of the 5th grade, students should know that
a. Things on or near the earth are pulled toward it by the earth's gravity.
b. Like all planets and stars, the earth is approximately spherical in shape. The rotation of the earth on its axis every 24 hours produces the night-and-day cycle. To people on earth, this turning of the planet makes it seem as though the sun, moon, planets, and stars are orbiting the earth once a day.
c. When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water.
d. Air is a substance that surrounds us, takes up space, and whose movement we feel as wind.
3. By the end of the 8th grade, students should know that
a. We live on a relatively small planet, the third from the sun in the only system of planets definitely known to exist (although other, similar systems may be discovered in the universe).
b. The earth is mostly rock. Three-fourths of its surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin blanket of air. It is the only body in the solar system that appears able to support life. The other planets have compositions and conditions very different from the earth's.
c. Everything on or anywhere near the earth is pulled toward the earth's center by gravitational force.
d. Because the earth turns daily on an axis that is tilted relative to the plane of the earth's yearly orbit around the sun, sunlight falls more intensely on different parts of the earth during the year. The difference in heating of the earth's surface produces the planet's seasons and weather patterns.
e. The moon's orbit around the earth once in about 28 days changes what part of the moon is lighted by the sun and how much of that part can be seen from the earth--the phases of the moon.
f. Climates have sometimes changed abruptly in the past as a result of changes in the earth's crust, such as volcanic eruptions or impacts of huge rocks from space. Even relatively small changes in atmospheric or ocean content can have widespread effects on climate if the change lasts long enough.
g. The cycling of water in and out of the atmosphere plays an important role in determining climatic patterns. Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow, and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the ocean.
h. Fresh water, limited in supply, is essential for life and also for most industrial processes. Rivers, lakes, and groundwater can be depleted or polluted, becoming unavailable or unsuitable for life.
i. Heat energy carried by ocean currents has a strong influence on climate around the world.
j. Some minerals are very rare and some exist in great quantities, but--for practical purposes-- the ability to recover them is just as important as their abundance. As minerals are depleted, obtaining them becomes more difficult. Recycling and the development of substitutes can reduce the rate of depletion but may also be costly.
k. The benefits of the earth's resources--such as fresh water, air, soil, and trees--can be reduced by using them wastefully or by deliberately or inadvertently destroying them. The atmosphere and the oceans have a limited capacity to absorb wastes and recycle materials naturally. Cleaning up polluted air, water, or soil or restoring depleted soil, forests, or fishing grounds can be very difficult and costly.
1. By the end of the 2nd grade, students should know that
a. Chunks of rocks come in many sizes and shapes, from boulders to grains of sand and even smaller.
b. Change is something that happens to many things.
c. Animals and plants sometimes cause changes in their surroundings.
2. By the end of the 5th grade, students should know that
a. Waves, wind, water, and ice shape and reshape the earth's land surface by eroding rock and soil in some areas and depositing them in other areas, sometimes in seasonal layers.
b. Rock is composed of different combinations of minerals. Smaller rocks come from the breakage and weathering of bedrock and larger rocks. Soil is made partly from weathered rock, partly from plant remains--and also contains many living organisms.
3. By the end of the 8th grade, students should know that
a. The interior of the earth is hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere.
b. Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges.
c. Sediments of sand and smaller particles (sometimes containing the remains of organisms) are gradually buried and are cemented together by dissolved minerals to form solid rock again.
d. Sedimentary rock buried deep enough may be reformed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it.
e. Thousands of layers of sedimentary rock confirm the long history of the changing surface of the earth and the changing life forms whose remains are found in the successive layers. The youngest layers are not always found on top, because of folding, breaking, and uplift of layers.
f. Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms.
g. Human activities, such as reducing the amount of forest cover, increasing the amount and variety of chemicals released into the atmosphere, and intensive farming, have changed the earth's land, oceans, atmosphere. Some of these changes have decreased the capacity of the environment to support some life forms.
1. By the end of the 2nd grade, students should know that
a. Objects can be described in terms of the materials they are made of (clay, cloth, paper, etc.) and their physical properties (color, size, shape, weight, texture, flexibility, etc.).
b. Things can be done to materials to change some of their properties, but not all materials respond the same way to what is done to them.
2. By the end of the 5th grade, students should know that
a. Heating and cooling cause changes in the properties of materials. Many kinds of changes occur faster under hotter conditions.
b. No matter how the parts of an object are assembled, the weight of the whole object made is always the same as the sum of the parts; and when a thing is broken into parts, the parts have the same total weight as the original thing.
c. Materials may be composed of parts that are too small to be seen without magnification.
d. When a new material is made by combining two or more materials, it has properties that are different from the original materials. For that reason, a lot of different materials can be made from a small number of basic kinds of materials.
3. By the end of the 8th grade, students should know that
a. All matter is made up of atoms, which are far too small to see directly through a microscope. The atoms of any element are alike but are different from atoms of other elements. Atoms may stick together in well-defined molecules or may be packed together in large arrays. Different arrangements of atoms into groups compose all substances.
b. Equal volumes of different substances usually have different weights.
c. Atoms and molecules are perpetually in motion. Increased temperature means greater average energy of motion, so most substances expand when heated. In solids, the atoms are closely locked in position and can only vibrate. In liquids, the atoms or molecules have higher energy of motion, are more loosely connected, and can slide past one another; some molecules may get enough energy to escape into gas. In gases, the atoms or molecules have still more energy of motion and are free of one another except during occasional collisions.
d. The temperature and acidity of a solution influence reaction rates. Many substances dissolve in water, which may greatly facilitate reactions between them.
e. Scientific ideas about elements were borrowed from some Greek philosophers of 2,000 years earlier, who believed that everything was made from four basic substances: air, earth, fire, and water. It was the combinations of these "elements" in different proportions that gave other substances their observable properties. The Greeks were wrong about those four, but now over 100 different elements have been identified, some rare and some plentiful, out of which everything is made. Because most elements tend to combine with others, few elements are found in their pure form.
f. There are groups of elements that have similar properties, including highly reactive metals, less reactive metals, highly reactive nonmetals (such as chlorine, fluorine, and oxygen), and some almost completely non reactive gases (such as helium and neon). An especially important kind of reaction between substances involves combination of oxygen with something else--as in burning or rusting. Some elements don't fit into any of the categories; among them are carbon and hydrogen, essential elements of living matter.
g. No matter how substances within a closed system interact with one another, or how they combine or break apart, the total weight of the system remains the same. The idea of atoms explains the conservation of matter: If the number of atoms stays the same no matter how they are rearranged, then their total mass stays the same.
1. By the end of the 2nd grade, students should know that
a. The sun warms the land, air, and water.
2. By the end of the 5th grade, students should know that
a. Things that give off light often also give off heat. Heat is produced by mechanical and electrical machines, and any time one thing rubs against something else.
b. When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature. A warmer object can warm a cooler one by contact or at a distance.
c. Some materials conduct heat much better than others. Poor conductors can reduce heat loss.
3. By the end of the 8th grade, students should know that
a. Energy cannot be created or destroyed, but only changed from one form into another.
b. Most of what goes on in the universe--from exploding stars and biological growth to the operation of machines and the motion of people--involves some form of energy being transformed into another. Energy in the form of heat is almost always one of the products of an energy transformation.
c. Heat can be transferred through materials by the collisions of atoms or across space by radiation. If the material is fluid, currents will be set up in it that aid the transfer of heat.
d. Energy appears in different forms. Heat energy is in the disorderly motion of molecules and in radiation; chemical energy is in the arrangement of atoms; mechanical energy is in moving bodies or in elastically distorted shapes; and electrical energy is in the attraction or repulsion between charges.
1. By the end of the 2nd grade, students should know that
a. Things move in many different ways, such as straight, zigzag, round and round, back and forth, and fast and slow.
b. The way to change how something is moving is to give it a push or a pull.
c. Things that make sound vibrate.
2. By the end of the 5th grade, students should know that
a. Something that is moving may move steadily or change its direction. The greater the force is, the greater the change in motion will be. The more massive on object is, the less effect a given force will have.
b. How fast things move differs greatly. Some things are so slow that their journey takes a long time; others move too fast for people to even see them.
3. By the end of the 8th grade, students should know that
a. Light from the sun is made up of a mixture of many different colors of light, even though to the eye the light looks almost white. Other things that give off or reflect light have a different mix of colors.
b. Something can be "seen" when light waves emitted or reflected by it enter the eye--just as something can be "heard" when sound waves from it enter the ear.
c. In the absence of retarding forces such as friction, an object will keep its direction of motion and its speed. Whenever an object is seen to speed up, slow down, or change direction, it can be assumed that an unbalanced force is acting on it.
d. Vibrations in materials set up wavelike disturbances that spread away from the source. Sound and earthquake waves are examples. These and other waves move at different speeds in different materials.
e. Human eyes respond to only a narrow range of wavelengths of electromagnetic radiation-- visible light. Differences of wavelength within that range are perceived as differences in color.
1. By the end of the 2nd grade, students should know tha
a. Things near the earth fall to the ground unless something holds them up.
b. Magnets can be used to make some things move without being touched.
2. By the end of the 5th grade, students should know that
a. The earth's gravity pulls any object toward it without touching it.
b. Without touching them, a magnet pulls on all things made of iron and either pushes or pulls on other magnets.
c. Without touching them, material that has been electrically charged pulls on all other materials and may either push or pull other charged materials.
3. By the end of the 8th grade, students should know that
a. Every object exerts gravitational force on every other object. The force depends on how much mass the objects have and on how far apart they are. The force is hard to detect unless at least one of the objects has a lot of mass.
b. The sun's gravitational pull holds the earth and other planets in their orbits, just as the planets' gravitational pull keeps their moons in orbit around them.
c. Electric currents and magnets can exert a force on each other.
1. By the end of the 2nd grade, students should know that
a. Some animals and plants are alike in the way they look and in the things they do, and others are very different from one another.
b. Plants and animals have features that help them live in different environments.
c. Stories sometimes give plants and animals attributes they really do not have.
2. By the end of the 5th grade, students should know that
a. A great variety of kinds of living things can be sorted into groups in many ways using various features to decide which things belong to which group.
b. Features used for grouping depend on the purpose of the grouping.
3. By the end of the 8th grade, students should know that
a. One of the most general distinctions among organisms is between plants, which use sunlight to make their own food, and animals, which consume energy-rich foods. Some kinds of organisms, many of them microscopic, cannot be neatly classified as either plants or animals.
b. Animals and plants have a great variety of body plans and internal structures that contribute to their being able to make or find food and reproduce.
c. Similarities among organisms are found in internal anatomical features, which can be used to infer the degree of relatedness among organisms. In classifying organisms, biologists consider details of internal and external structures to be more important than behavior or general appearance.
d. For sexually reproducing organisms, a species comprises all organisms that can mate with one another to produce fertile offspring.
e. All organisms, including the human species, are part of and depend on two main interconnected global food webs. One includes microscopic ocean plants, the animals that feed on them, and finally the animals that feed on those animals. The other web includes land plants, the animals that feed on them, and so forth. The cycles continue indefinitely because organisms decompose after death to return food material to the environment.
1. By the end of the 2nd grade, students should know that
a. There is variation among individuals of on kind within a population.
b. Offspring are very much, but not exactly, like their parents and like one another.
2. By the end of the 5th grade, students should know that
a. Some likenesses between children and parents, such as eye color in human beings, or fruit or flower color in plants, are inherited. Other likenesses, such as people's table manners or carpentry skills, are learned.
b. For offspring to resemble their parents, there must be a reliable way to transfer information from one generation to the next.
3. By the end of the 8th grade, students should know that
a. In some kinds of organisms, all the genes come from a single parent, whereas in organisms that have sexes, typically half of the genes come from each parent.
b. In sexual reproduction, a single specialized cell from a female merges with a specialized cell from a male. As the fertilized egg, carrying genetic information from each parent, multiplies to form the complete organism with about a trillion cells, the same genetic information is copied in each cell.
c. New varieties of cultivated plants and domestic animals have resulted from selective breeding for particular traits.
1. By the end of the 2nd grade, students should know that
a. Magnifiers help people see things they could not see without them.
b. Most living things need water, food, and air.
2. By the end of the 5th grade, students should know that
a. Some living things consist of a single cell. Like familiar organisms, they need food, water, and air; a way to dispose of waste; and an environment they can live in.
b. Microscopes make it possible to see that living things are made mostly of cells. Some organisms are made of a collection of similar cells that benefit from cooperating. Some organisms' cells vary greatly in appearance and perform very different roles in the organism.
3. By the end of the 8th grade, students should know that
a. All living things are composed of cells, from just one to many millions, whose details usually are visible only through a microscope. Different body tissues and organs are made up of different kinds of cells. The cells in similar tissues and organs in other animals are similar to those in human beings but differ somewhat from cells found in plants.
b. Cells continually divide to make more cells for growth and repair. Various organs and tissues function to serve the needs of cells for food, air, and waste removal.
c. Within cells, many of the basic functions of organisms--such as extracting energy from food and getting rid of waste--are carried out. The way in which cells function is similar in all living organisms.
d. About two thirds of the weight of cells is accounted for by water, which gives cells many of their properties.
1. By the end of the 2nd grade, students should know that
a. Animals eat plants or other animals for food and may also use plants (or even other animals) for shelter and nesting.
b. Living things are found almost everywhere in the world. There are somewhat different kinds in different places.
2. By the end of the 5th grade, students should know that
a. For any particular environment, some kinds of plants and animals survive well, some survive less well, and some cannot survive at all.
b. Insects and various other organisms depend on dead plant and animal material for food.
c. Organisms interact with one another in various ways besides providing food. Many plants depend on animals for carrying their pollen to other plants or for dispersing their seeds.
d. Changes in an organism's habitat are sometimes beneficial to it and sometimes harmful.
e. Most microorganisms do not cause disease, and many are beneficial.
3. By the end of the 8th grade, students should know that
a. In all environments--freshwater, marine, forest, desert, grassland, mountain, and others-- organisms with similar needs may compete with one another for resources, including food, space, water, air, and shelter. In any particular environment, the growth and survival of organisms depend on the physical conditions.
b. Two types of organisms may interact with one another in several ways: They may be in a producer/consumer, predator/prey, or parasite/host relationship. Or one organism may scavenge or decompose another. Relationships may be competitive or mutually beneficial. Some species have become so adapted to each other that neither could survive without the other.
1. By the end of the 2nd grade, students should know that
a. Plants and animals both need to take in water, and animals need to take in food. In addition, plants need light.
b. Many materials can be recycled and used again, sometimes in different forms.
2. By the end of the 5th grade, students should know that
a. Almost all kinds of animals' food can be traced back to plants.
b. Some source of "energy" is needed for all organisms to stay alive and grow.
c. Over the whole earth, organisms are growing, dying, and decaying, and new organisms are being produced by the old ones.
3. By the end of the 8th grade, students should know that
a. Food provides the fuel and the building material for all organisms. Plants use the energy from light to make sugars from carbon dioxide and water. This food can be used immediately or stored for later use. Organisms that eat plants break down the plant structures to produce the materials and energy they need to survive. Then they are consumed by other organisms.
b. Over a long time, matter is transferred from one organism to another repeatedly and between organisms and their physical environment. As in all material systems, the total amount of matter remains constant, even though its form and location change.
c. Energy can change from one form to another in living things. Animals get energy from oxidizing their food, releasing some of its energy as heat. Almost all food energy comes originally from sunlight.
1. By the end of the 2nd grade, students should know that
a. Different plants and animals have external features that help them thrive in different kinds of places.
b. Some kinds of organisms that once lived on earth have completely disappeared, although they were something like others that are alive today.
2. By the end of the 5th grade, students should know that
a. Individuals of the same kind differ in their characteristics, and sometimes the differences give individuals an advantage in surviving and reproducing.
b. Fossils can be compared to one another and to living organisms according to their similarities and differences. Some organisms that lived long ago are similar to existing organisms, but some are quite different.
3. By the end of the 8th grade, students should know that
a. Small differences between parents and offspring can accumulate (through selective breeding) in successive generations so that descendants are very different from their ancestors.
b. Individual organisms with certain traits are more likely than others to survive and have offspring. Changes in environmental conditions can affect the survival of individual organisms and entire species.
c. Many thousands of layers of sedimentary rock provide evidence for the long history of the earth and for the long history of changing life forms whose remains are found in the rocks. More recently deposited rock layers are more likely to contain fossils resembling existing species.
1. By the end of the 2nd grade, students should know that
a. People have different external features, such as the size, shape, and color of hair, skin, and eyes, but they are more like one another than like other animals.
b. People need water, food, air, waste removal, and a particular range of temperatures in their environment, just as other animals do.
c. People tend to live in families and communities in which individuals have different roles.
2. By the end of the 5th grade, students should know that
a. Unlike in human beings, behavior in insects and many other species is determined almost entirely by biological inheritance.
b. Human beings have made tools and machines to sense and do things that they could not otherwise sense or do at all, or as quickly, or as well.
c. Artifacts and preserved remains provide some evidence of the physical characteristics and possible behavior of human beings who lived a very long time ago.
3. By the end of the 8th grade, students should know that
a. Like other animals, human beings have body systems for obtaining and providing energy, defense, reproduction, and the coordination of body functions.
b. Human beings have many similarities and differences. The similarities make it possible for human beings to reproduce and to donate blood and organs to one another throughout the world. Their differences enable them to create diverse social and cultural arrangements and to solve problems in a variety of ways.
c. Fossil evidence is consistent with the idea that human beings evolved from earlier species.
d. Specialized roles of individuals within other species are genetically programmed, whereas human beings are able to invent and modify a wider range of social behavior.
e. Human beings use technology to match or excel many of the abilities of other species. Technology has helped people with disabilities survive and live more conventional lives.
f. Technologies having to do with food production, sanitation, and disease prevention have dramatically changed how people live and work and have resulted in rapid increases in the human population.
1. By the end of the 2nd grade, students should know that
a. All animals have offspring, usually with two parents involved. People may prevent some animals from producing offspring.
b. A human baby grows inside its mother until its birth. Even after birth, a human baby is unable to care for itself, and its survival depends on the care it receives from adults.
2. By the end of the 5th grade, students should know that
a. It takes about 9 months for a human embryo to develop. Embryos are nourished by the mother, so substances she takes in will affect how well or poorly the baby develops.
b. Human beings live longer than most other animals, but all living things die.
c. There is a usual sequence of physical and mental development among human beings, although individuals differ in exactly when they learn things.
d. People are usually able to have children before they are able to care for them properly.
3. By the end of the 8th grade, students should know that
a. Fertilization occurs when sperm cells from a male's testes are deposited near an egg cell from the female ovary, and one of the sperm cells enters the egg cell. Most of the time, by chance or design, a sperm never arrives or an egg isn't available.
b. Contraception measures may incapacitate sperm, block their way to the egg, prevent the release of eggs, or prevent the fertilized egg from implanting successfully.
c. Following fertilization, cell division produces a small cluster of cells that then differentiate by appearance and function to form the basic tissues of an embryo. During the first three months of pregnancy, organs begin to form. During the second three months, all organs and body features develop. During the last three months, the organs and features mature enough to function well after birth. Patterns of human development are similar to those of other vertebrates.
d. The developing embryo--and later the newborn infant--encounters many risks from faults in its genes, its mother's inadequate diet, her cigarette smoking or use of alcohol or other drugs, or from infection. Inadequate child care may lead to lower physical and mental ability.
e. Various body changes occur as adults age. Muscles and joints become less flexible, bones and muscles lose mass, energy levels diminish, and the senses become less acute. Women stop releasing eggs and hence can no longer reproduce. The length and quality of human life are influenced by many factors, including sanitation, diet, medical care, sex, genes, environmental conditions, and personal health behaviors.
1. By the end of the 2nd grade, students should know that
a. The human body has parts that help it seek, find, and take in food when it feels hunger-- eyes and noses for detecting food, legs to get to it, arms to carry it away, and a mouth to eat it.
b. Senses can warn individuals about danger; muscles help them to fight, hide, or get out of danger.
c. The brain enables human beings to think and sends messages to other body parts to help them work properly.
2. By the end of the 5th grade, students should know that
a. From food, people obtain energy and materials for body repair and growth. The undigestible parts of food are eliminated.
b. By breathing, people take in the oxygen they need to live.
c. Skin protects the body from harmful substances and other organisms and from dying out.
d. The brain gets signals from all parts of the body telling what is going on there. The brain also sends signals to parts of the body to influence what they do.
3. By the end of the 8th grade, students should know that
a. Organs and organ systems are composed of cells and help to provide all cells with basic needs.
b. For the body to use food for energy and building materials, the food must first be digested into molecules that are absorbed and transported to cells.
c. To burn food for the release of energy stored in it, oxygen must be supplied to cells, and carbon dioxide removed. Lungs take in oxygen for the combustion of food and they eliminate the carbon dioxide produced. The urinary system disposes of dissolved waste molecules, the intestinal tract removes solid wastes, and the skin and lungs rid the body of heat energy. The circulatory system moves all these substances to or from cells where they are needed or produced, responding to changing demands.
d. Specialized cells and the molecules they produce identify and destroy microbes that get inside the body.
e. Hormones are chemicals from glands that affect other body parts. They are involved in helping the body respond to danger and in regulating human growth, development, and reproduction.
f. Interactions among the senses, nerves, and brain make possible the learning that enables human beings to cope with changes in their environment.
1. By the end of the 2nd grade, students should know that
a. People use their senses to find out about their surroundings and themselves. Different senses give different information. Sometimes a person can get different information about the same thing by moving closer to it or further away from it.
b. Some of the things people do, like playing soccer, reading, and writing, must be deliberately learned. Practicing helps people to improve. How well one learns sometimes depends on how one does it and how often and how hard one tries to learn.
c. People can learn from each other by telling and listening, showing and watching, and imitating what others do.
2. By the end of the 5th grade, students should know that
a. Human beings have different interests, motivations, skills, and talents.
b. Human beings can use the memory of their past experiences to make judgments about new situations.
c. Many skills can be practiced until they become automatic. If the right skills are practiced, performance may improve.
d. Human beings tend to repeat behaviors that feel good or have pleasant consequences and avoid behaviors that feel bad or have unpleasant consequences.
e. Learning means using what one already knows to make sense out of new experiences or information, not just storing the new information in one's head.
3. By the end of the 8th grade, students should know that
a. Some animal species are limited to a repertoire of genetically determined behaviors; others have more complex brains and can learn a wide variety of behaviors. All behavior is affected by both inheritance and experience.
b. The level of skill a person can reach in any particular activity depends on innate abilities, the amount of practice, and the use of appropriate learning technologies.
c. Human beings can detect a tremendous range of visual and olfactory stimuli. The strongest stimulus they can tolerate may be more than a trillion times as intense as the weakest they can detect. Still, there are many kinds of signals in the world that people cannot detect directly.
d. Attending closely to any one input of information usually reduces the ability to attend to others at the same time.
e. Learning often results from two perceptions or actions occurring at about the same time. The more often the same combination occurs, the stronger the mental connection between them is likely to be. Occasionally a single vivid experience will connect two things permanently in people's minds.
f. Language and tools enable human beings to learn complicated and varied things from others.
1. By the end of the 2nd grade, students should know that
a. Eating a variety of healthful foods and getting enough exercise and rest help people to stay healthy.
b. Some things people take into their bodies from the environment can hurt them.
c. Some diseases are caused by germs, some are not. Diseases caused by germs may be spread by people who have them. Washing one's hands with soap and water reduces the number of germs that can get into the body or that can be passed on to other people.
2. By the end of the 5th grade, students should know that
a. Food provides energy and materials for growth and repair of body parts. Vitamins and minerals, present in small amounts in foods, are essential to keep everything working well. As people grow up, the amounts and kinds of food and exercise needed by the body may change.
b. Tobacco, alcohol, other drugs, and certain poisons in the environment (pesticides, lead) can harm human beings and other living things.
c. If germs are able to get inside one's body, they may keep it from working properly. For defense against germs, the human body has tears, saliva, skin, some blood cells, and stomach secretions. A healthy body can fight most germs that do get inside. However, there are some germs that interfere with the body's defenses.
3. By the end of the 8th grade, students should know that
a. The amount of food energy (calories) a person requires varies with body weight, age, sex, activity level, and natural body efficiency. Regular exercise is important to maintain a healthy heart/lung system, good muscle tone, and bone strength.
b. Toxic substances, some dietary habits, and personal behavior may be bad for one's health. Some effects show up right away, others may not show up for many years. Avoiding toxic substances such as tobacco, and changing dietary habits to reduce the intake of such things as animal fat increases the chances of living longer.
c. Viruses, bacteria, fungi, and parasites may infect the human body and interfere with normal body functions. A person can catch a cold many times because there are many varieties of cold viruses that cause similar symptoms.
d. White blood cells engulf invaders or produce antibodies that attack them or mark them for killing by other white cells. The antibodies produced will remain and can fight off subsequent invaders of the same kind.
e. The environment may contain dangerous levels of substances that are harmful to human beings. Therefore, the good health of individuals requires monitoring the soil, air, and water and taking steps to keep them safe.
1. By the end of the 2nd grade, students should know that
a. People have many different feelings--sadness, joy, anger, fear, etc.--about events, themselves, and other people.
b. People react to personal problems in different ways. Some ways are more likely to be helpful than others. Talking to someone (a friend, relative, teacher, or counselor) may help people understand their feelings and problems and what to do about them.
2. By the end of the 5th grade, students should know that
a. Different individuals handle their feelings differently, and sometimes they have different feelings in the same situation.
b. Often human beings don't understand why others act the way they do, and sometimes they don't understand their own behavior and feelings.
c. Physical health can affect people's emotional well-being and vice versa.
d. One way to respond to a strong feeling, either pleasant or unpleasant, is to think about what caused it and then consider whether to seek out or avoid similar situations.
3. By the end of the 8th grade, students should know that
a. Individuals differ greatly in their ability to cope with stressful situations. Both external and internal conditions (chemistry, personal history, values) influence how people behave.
b. Often people react to mental distress by denying that they have any problem. Sometimes they don't know why they feel the way they do, but with help they can sometimes uncover the reasons.
1. By the end of the 2nd grade, students should know that
a. People are alike in many ways and different in many ways.
b. Different families or classrooms have different rules and patterns of behavior. Some behaviors are not accepted in most families or schools.
c. People often choose to dress, talk, and act like their friends, do the same things they do, and have the same kinds of things they have. They also often choose to do certain things their own way.
2. By the end of the 5th grade, students should know that
a. People can learn about others from direct experience, from the mass communications media, and from listening to other people talk about their work and their lives. People also sometimes imitate people --or characters--in the media.
b. People tend to feel uncomfortable with other people who dress, talk, or act very differently from themselves. What is considered to be acceptable human behavior varies from culture to culture and from one time period to another, but there are some behaviors that are unacceptable in almost all cultures, past and present.
3. By the end of the 8th grade, students should know that
a. Each culture has distinctive patterns of behavior, usually practiced by most of the people who grow up in it.
b. Within a large society, there may be many groups, with distinctly different subcultures associated with region, ethnic origin, or social class.
c. Although within any society there is usually broad general agreement on what behavior is unacceptable, the standards used to judge behavior vary for different settings and different subgroups, and they may change with time and different political and economic conditions. Moreover, the punishments vary widely among, and even within, different societies.
d. Technology, especially in transportation and communication, is increasingly important in spreading ideas, values, and behavior patterns within a society and among different societies. New technology can change cultural values and social behavior.
1. By the end of the 2nd grade, students should know that
a. People belong to some groups by birth and belong to some groups because they join them.
b. The way people act is often influenced by the groups to which they belong.
2. By the end of the 5th grade, students should know that
a. People often like or dislike other people because of membership in or exclusion from a particular social group. Individuals tend to support members of their own group and perceive them as being like themselves.
b. Different groups have different expectations for how their members should act. Sometimes the rules are written down and strictly enforced, sometimes they are just understood from example.
c. When acting together, members of a group and even people in a crowd sometimes do and say things, good or bad, that they would not do or say on their own.
3. By the end of the 8th grade, students should know that
a. Affiliation with a group can increase the power of members through pooled resources and concerted action. Joining a group often has personal advantages, such as companionship, a sense of identity, and recognition by others inside and outside the group. Group identity may create a feeling of superiority, which increases group cohesion but may also entail hostility toward other groups.
b. People sometimes react to all members of a group as though they were the same and perceive in their behavior only those qualities that fit preconceptions of the group. Such stereotyping leads to uncritical judgments, such as showing blind respect for members of some groups and equally blind disrespect for members of other groups.
1. By the end of the 2nd grade, students should know that
a. Changes happen in everyone's life, sometimes suddenly, more often slowly. People cannot control some changes, but they can usually learn to cope with them.
2. By the end of the 5th grade, students should know that
a. Although rules at home, school, church, and in the community stay mostly the same, sometimes they change. Changes in social arrangements happen because some rules do not work or new people are involved or outside circumstances change.
b. Rules and laws can sometimes be changed by getting most of the people they affect to agree to change them.
3. By the end of the 8th grade, students should know that
a. Some aspects of family and community life are the same now as they were a generation ago, but some aspects are very different. What is taught in school and school policies toward student behavior have changed over the years in response to family and community pressures,
b. By the way they depict the ideas and customs of one culture, communications media may stimulate changes in others.
c. Migration, conquest, and natural disasters have been major factors in causing social and cultural change.
1. By the end of the 2nd grade, students should know that
a. Getting something one wants may mean giving up something in return.
b. Different people may make different choices for different reasons.
c. Choices have consequences, some of which are more serious than others.
2. By the end of the 5th grade, students should know that.
a. In making decisions, it helps to take time to consider the benefits and drawbacks of alternatives.
b. In making decisions, benefits and drawbacks of alternatives can be taken into account more effectively if the people who will be affected are involved.
c. Sometimes social decisions have unexpected consequences, no matter how carefully the decisions are made.
3. By the end of the 8th grade, students should know that
a. There are trade-offs that each person must consider in making choices--about personal popularity, health, family relations, and education, for example--that often have life-long consequences.
b. One common aspect of all social trade-offs pits personal benefit and the rights of the individual, on one side, against the social good and the rights of society, on the other.
c. Trade-offs are not always between desirable possibilities. Sometimes social and personal trade-offs require accepting an unwanted outcome to avoid some other unwanted one.
1. By the end of the 2nd grade, students should know that
a. Money can buy things that people need or want. People earn money by working at a job making or growing things, selling things, or doing things to help other people.
b. Everyone wants to be treated fairly, and some rules can help to do that.
2. By the end of the 5th grade, students should know that
a. People tend to live together in groups and therefore have to have ways of deciding who will do what.
b. Services that everyone gets, such as schools, libraries, parks, mail service, and police and fire protection, are usually provided by government.
c. There are not enough resources to satisfy all of the desires of all people, and so there has to be some way of deciding who gets what.
d. Some jobs require more (or more expensive) training than others, some involve more risk, and some pay better.
3. By the end of the 8th grade, students should know that
a. Government provides some goods and services through its own agencies and some through contracts with private individuals or businesses. To pay for the goods and services, government must obtain money by taxing people or by borrowing money.
b. Government leaders come into power by election, appointment, or force.
c. However they are formed, governments usually have most of the power to make, interpret, and enforce the rules and decisions that determine how a community, state, or nation will be run. Many of the rules established by governments are designed to reduce social conflict. The rules affect a wide range of human affairs, from marriage and education to scientific research and commerce.
d. In a central-planning model, a single authority, usually a national government, decides what to produce, how to produce it, and for whom. In a free-market model, consumers and producers (individually or in organizations) make these decisions based on what they believe will benefit themselves. No real-world economy is a pure example of either model; all economies have some features of each kind.
1. By the end of the 2nd grade, students should know that
a. Disagreements are common, even between family members or friends. Some ways of dealing with them work better than others. People who are not involved in an argument may be helpful in solving it.
b. Rules at home, at school, and in the community let individuals know what to expect so they can reduce the number or disputes.
2. By the end of the 5th grade, students should know that
a. Communicating the different points of view in a dispute can often help people to find a satisfactory compromise.
b. Resolving a conflict by force rather than compromise can lead to more problems.
c. One person's exercise of freedom may conflict with the freedom of others. Rules can help to resolve conflicting freedoms.
d. If a conflict cannot be settled by compromise, it may be decided by a vote--if everyone agrees to accept the results.
3. By the end of the 8th grade, students should know that
a. Being a member of a group can increase an individual's social power or hostile actions against other groups or individuals. It may also subject that person to the hostility of people who are outside the group.
b. Most groups have formal or informal procedures for arbitrating disputes among their members.
1. By the end of the 2nd grade, students should know that
a. For many things they need, people rely on others who are not part of the family and maybe not even part of their local community.
2. By the end of the 5th grade, students should know that
a. Many of the things people eat and wear come from other countries, and people in those countries use things from this country. Trade occurs between nations, between different people, and between regions in the same nation. Decisions made in one country about what is produced there may have an effect on other countries.
3. By the end of the 8th grade, students should know that
a. Trade between nations occurs when natural resources are unevenly distributed and the costs of production are very different in different countries. A nation has a trade opportunity whenever it can create more of a product or service at a lower cost than another.
b. The major ways to promote economic health are to encourage technological development, to increase the quantity or quality of a nation's productive resources--more or better-trained workers, better equipment and methods--and to engage in trade with other nations.
c. The purpose of treaties being negotiated directly between individual countries or by international organizations is to bring about cooperation among countries.
d. Scientists are linked to other scientists worldwide both personally and through international scientific organizations.
e. The global environment is affected by national policies and practices relating to energy use, waste disposal, ecological management, manufacturing, and population.
1. By the end of the 2nd grade, students should know that
a. Most food comes from farms either directly as crops or as the animals that eat the crops. To grow well, plants need enough warmth, light, and water. Crops also must be protected from weeds and pests that can harm them.
b. Part of a crop may be lost to pests or spoilage.
c. A crop that is fine when harvested may spoil before it gets to consumers.
d. Machines improve what people get from crops by helping in planting and harvesting, in keeping food fresh by packaging and cooling, and in moving it long distances from where it is grown to where people live.
2. By the end of the 5th grade, students should know that
a. Some plant varieties and animal breeds have more desirable characteristics than others, but some may be more difficult or costly to grow. The kinds of crops that can grow in an area depend on the climate and soil. Irrigation and fertilizers can help crops grow in places where there is too little water or the soil is poor.
b. The damage to crops caused by rodents, weeds, and insects can be reduced by using poisons, but their use may harm other plants or animals as well, and pests tend to develop resistance to poisons.
c. Heating, salting, smoking, drying, cooling, and airtight packaging are ways to slow down the spoiling of food by microscopic organisms. These methods make it possible for food to be stored for long intervals before being used.
d. Modern technology has increased the efficiency of agriculture so that fewer people are needed to work on farms than ever before.
e. Places too cold or dry to grow certain crops can obtain food from places with more suitable climates. Much of the food eaten by Americans comes from other parts of the country and other places in the world.
3. By the end of the 8th grade, students should know that
a. Early in human history, there was an agricultural revolution in which people changed from hunting and gathering to farming. This allowed changes in the division of labor between men and women and between children and adults, and the development of new patterns of government.
b. People control the characteristics of plants and animals they raise by selective breeding and by preserving varieties of seeds (old and new) to use if growing conditions change.
c. In agriculture, as in all technologies, there are always trade-offs to be made. Getting food from many different places makes people less dependent on weather in any one place, yet more dependent on transportation and communication among far-flung markets. Specializing in one crop may risk disaster if changes in weather or increases in pest populations wipe out that crop. Also, the soil may be exhausted of some nutrients, which can be replenished by rotating the right crops.
d. Many people work to bring food, fiber, and fuel to U.S. markets. With improved technology, only a small fraction of workers in the United States actually plant and harvest the products that people use. Most workers are engaged in processing, packaging, transporting, and selling what is produced.
1. By the end of the 2nd grade, students should know that
a. Some kinds of materials are better than others for making any particular thing. Materials that are better in some ways (such as stronger or cheaper) may be worse in other ways (heavier or harder to cut).
b. Several steps are usually involved in making things.
c. Tools are used to help make things, and some things cannot be made at all without tools. Each kind of tool has a special purpose.
d. Some materials can be used over again.
2. By the end of the 5th grade, students should know that
a. Naturally occurring materials such as wood, clay, cotton, and animal skins may be processed or combined with other materials to change their properties.
b. Through science and technology, a wide variety of materials that do not appear in nature at all have become available, ranging from steel to nylon to liquid crystals.
c. Discarded products contribute to the problem of waste disposal. Sometimes it is possible to use the materials in them to make new products, but materials differ widely in the ease with which they can be recycled.
d. Through mass production, the time required to make a product and its cost can be greatly reduced. Although many things are still made by hand in some parts of the world, almost everything in the most technologically developed countries is now produced using automatic machines. Even automatic machines require human supervision.
3. By the end of the 8th grade, students should know that
a. The choice of materials for a job depends on their properties and on how they interact with other materials. Similarly, the usefulness of some manufactured parts of an object depends on how well they fit together with the other parts.
b. Manufacturing usually involves a series of steps, such as designing a product, obtaining and preparing raw materials, processing the materials mechanically or chemically, and assembling, testing, inspecting, and packaging. The sequence of these steps is also often important.
c. Modern technology reduces manufacturing costs, produces more uniform products, and creates new synthetic materials that can help reduce the depletion of some natural resources.
d. Automation, including the use of robots, has changed the nature of work in most fields, including manufacturing. As a result, high-skill, high-knowledge jobs in engineering, computer programming, quality control, supervision, and maintenance are replacing many routine, manual-labor jobs. Workers therefore need better learning skills and flexibility to take on new and rapidly changing jobs.
1. By the end of the 2nd grade, students should know that
a. People can save money by turning off machines when they are not using them.
b. People burn fuels such as wood, oil, coal, or natural gas, or use electricity to cook their food and warm their houses.
2. By the end of the 5th grade, students should know that
a. Moving air and water can be used to run machines.
b. The sun is the main source of energy for people and they use it in various ways. The energy in fossil fuels such as oil and coal comes from the sun indirectly, because the fuels come from plants that grew long ago.
c. Some energy sources cost less than others and some cause less pollution than others.
d. People try to conserve energy in order to slow down the depletion of energy resources and/or to save money.
3. By the end of the 8th grade, students should know that
a. Energy can change from one form to another, although in the process some energy is always converted to heat. Some systems transform energy with less loss of heat than others.
b. Different ways of obtaining, transforming, and distributing energy have different environmental consequences.
c. In many instances, manufacturing and other technological activities are performed at a site close to an energy source. Some forms of energy are transported easily, others are not.
d. Electrical energy can be produced from a variety of energy sources and can be transformed into almost any other form of energy. Moreover, electricity is used to distribute energy quickly and conveniently to distant locations.
e. Energy from the sun (and the wind and water energy derived from it) is available indefinitely. Because the flow of energy is weak and variable, very large collection systems are needed. Other sources don't renew or renew only slowly.
f. Different parts of the world have different amounts and kinds of energy resources to use and use them for different purposes.
1. By the end of the 2nd grade, students should know that
a. Information can be sent and received in many different ways. Some allow answering back and some do not. Each way has advantages and disadvantages.
b. Devices can be used to send and receive messages quickly and clearly.
2. By the end of the 5th grade, students should know that
a. People have always tried to communicate with one another. Signed and spoken language was one of the first inventions. Early forms of recording messages used markings on materials such as wood or stone.
b. Communication involves coding and decoding information. In any language, both the sender and the receiver have to know the same code, which means that secret codes can be used to keep communication private.
c. People have invented devices, such as paper and ink, engraved plastic disks, and magnetic tapes, for recording information. These devices enable great amounts of information to be stored and retrieved--and be sent to one or many other people or places.
d. Communication technologies make it possible to send and receive information more and more reliably, quickly, and cheaply over long distances.
3. By the end of the 8th grade, students should know that
a. Errors can occur in coding, transmitting, or decoding information, and some means of checking for accuracy is needed. Repeating the message is a frequently used method.
b. Information can be carried by many media, including sound, light, and objects. In this century, the ability to code information as electric currents in wires, electromagnetic waves in space, and light in glass fibers has made communication million of times faster than is possible by mail or sound.
1. By the end of the 2nd grade, students should know that
a. There are different ways to store things so they can be easily found later.
b. Letters and numbers can be used to put things in a useful order.
2. By the end of the 5th grade, students should know that
a. Computers are controlled partly by how they are wired and partly by special instructions called programs that are entered into a computer's memory. Some programs stay permanently in the machine but most are coded on disks and transferred into and out of the computer to suit the user.
b. Computers can be programmed to store, retrieve, and perform operations on information. These operations include mathematical calculations, word processing, diagram drawing, and the modeling of complex events.
c. Mistakes can occur when people enter programs or data into a computer. Computers themselves can make errors in information processing because of defects in their hardware of software.
3. By the end of the 8th grade, students should know that
a. Most computers use digital codes containing only two symbols, 0 and 1, to perform all operations. Continuous signals (analog) must be transformed into digital codes before they can be processed by a computer.
b. What use can be made of a large collection of information depends upon how it is organized. One of the values of computers is that they are able, on command, to reorganize information in a variety of ways, thereby enabling people to make more and better uses of the collection.
c. Computer control of mechanical systems can be much quicker that human control. In situations where events happen faster than people can react, there is little choice but to rely on computers. Most complex systems still require human oversight, however, to make certain kinds of judgments about the readiness of the parts of the system (including the computers) and the system as a whole to operate properly, to react to unexpected failures, and to evaluate how well the system is serving its intended purposes.
d. An increasing number of people work at jobs that involve processing or distributing information. Because computers can do these tasks faster and more reliably, they have become standard tools both in the workplace and at home.
1. By the end of the 2nd grade, students should know that
a. Vaccinations and other scientific treatments protect people from getting certain diseases, and different kinds of medicines may help those who do become sick to recover.
2. By the end of the 5th grade, students should know that
a. There are normal ranges for body measurements--including temperature, heart rate, and what is in the blood and urine--that help to tell when people are well. Tools, such as thermometers and x-ray machines, provide us with clues about what is happening inside the body.
b. Technology has made it possible to repair and sometimes replace some body parts.
3. By the end of the 8th grade, students should know that
a. Sanitation measures such as the use of sewers, landfills, quarantines, and safe food handling are important in controlling the spread of organisms that cause disease. Improving sanitation to prevent disease has contributed more to saving human life than any advance in medical treatment.
b. The ability to measure the level of substances in body fluids has made it possible for physicians to make comparisons with normal levels, make very sophisticated diagnoses, and monitor the effects of the treatments they prescribe.
c. It is becoming increasingly possible to manufacture chemical substances such as insulin and hormones that are normally found in the body. They can be used by individuals whose own bodies cannot produce the amounts required for good health.
1. By the end of the 2nd grade, students should know that
a. Numbers can be used to count things, place them in order, or name them.
b. Sometimes in sharing or measuring there is a need to use numbers between whole numbers.
c. It is possible (and often useful) to estimate quantities without knowing them exactly.
d. Simple graphs can help to tell about observations.
2. By the end of the 5th grade, students should know that
a. The meaning of numerals in many-digit numbers depends on their positions.
b. In some situations, "0" means none of something, but in others it may be just the label of some point on a scale.
c. When people care about what is being counted or measured, it is important for them to say what the units are (three degrees Fahrenheit is different from three centimeters, three miles from three miles per hour).
3. By the end of the 8th grade, students should know that
a. There have been systems for writing numbers other than the Arabic system of place values based on tens. The very old Roman numerals are now used only for dates, clock faces, or ordering chapters in a book. Numbers based on 60 are still used for describing time and angles.
b. A number line can be extended on the other side of zero to represent negative numbers. Negative numbers allow subtraction of a bigger number from a smaller number to make sense, and are often used when something can be measured on either side of some reference point (time, ground level, temperature, budget).
c. Numbers can be written in different forms, depending on how they are being used. How fractions or decimals based on measured quantities should be written depends on how precise the measurements are and how precise an answer is needed.
d. The operations + and - are inverses of each other--one undoes what the other does; likewise x and /.
e. The expression a/b can mean different things: a parts of size 1/b each, a divided by b, or a compared to b.
f. Numbers can be represented by using sequences of only two symbols (such as 1 and 0, on and off); computers work this way.
g. Computations (as on calculators) can give more digits than make sense or are useful.
1. By the end of the 2nd grade, students should know that
a. Similar patterns may show up in many places in nature and in the things people make.
b. Sometimes changing one thing causes changes in something else. In some situations, changing the same thing in the same way usually has the same result.
2. By the end of the 5th grade, students should know that
a. Mathematical statements using symbols may be true only when the symbols are replaced by certain numbers.
b. Tables and graphs can show how values of one quantity are related to values of another.
3. By the end of the 8th grade, students should know that
a. An equation containing a variable may be true for just one value of the variable.
b. Mathematical statements can be used to describe how one quantity changes when another changes. Rates of change can be computed from magnitudes and vice versa.
c. Graphs can show a variety of possible relationships between two variables. As one variable increases uniformly, the other may do one of the following: always keep the same proportion to the first, increase or decrease steadily, increase or decrease faster and faster, get closer and closer to some limiting value, reach some intermediate maximum or minimum, alternately increase and decrease indefinitely, increase or decrease in steps, or do something different from any of these.
1. By the end of the 2nd grade, students should know that
a. Shapes such as circles, squares, and triangles can be used to describe many things that can be seen.
2. By the end of the 5th grade, students should know that
a. Length can be thought of as unit lengths joined together, area as a collection of unit squares, and volume as a set of unit cubes.
b. If 0 and 1 are located on a line, any other number can be depicted as a position on the line.
c. Graphical display of numbers may make it possible to spot patterns that are not otherwise obvious, such as comparative size and trends.
d. Many objects can be described in terms of simple plane figures and solids. Shapes can be compared in terms of concepts such as parallel and perpendicular, congruence and similarity, and symmetry. Symmetry can be found by reflection, turns, or slides.
e. Areas of irregular shapes can be found by dividing them into squares and triangles.
f. Scale drawings show shapes and compare locations of things very different in size.
3. By the end of the 8th grade, students should know that
a. Some shapes have special properties: Triangular shapes tend to make structures rigid, and round shapes give the least possible boundary for a given amount of interior area. Shapes can match exactly or have the same shape in different sizes.
b. Lines can be parallel, perpendicular, or oblique.
c. Shapes on a sphere like the earth cannot be depicted on a flat surface without some distortion.
d. The graphic display of numbers may help to show patterns such as trends, varying rates of change, gaps, or clusters. Such patterns sometimes can be used to make predictions about the phenomena being graphed.
e. It takes two numbers to locate a point on a map or any other flat surface. The numbers may be two perpendicular distances from a point, or an angle and a distance from a point.
f. The scale chosen for a graph or drawing makes a big difference in how useful it is.
1. By the end of the 2nd grade, students should know that
a. Some things are more likely to happen than others. Some events can be predicted well and some cannot. Sometimes people aren't sure what will happen because they don't know everything that might be having an effect.
b. Often a person can find out about a group of things by studying just a few of them.
2. By the end of the 5th grade, students should know that
a. Some predictions can be based on what is known about the past, assuming that conditions are pretty much the same now.
b. Statistical predictions (as for rainy days, accidents) are typically better for what proportion of a group will experience something than for which members of the group will experience it--and better for how often something will happen than for exactly when.
c. Summary predictions are usually more accurate for large collections of events than for just a few. Even very unlikely events may occur fairly often in very large populations.
d. Spreading data out on a number line helps to see what the extremes are, where they pile up, and where the gaps are. A summary of data includes where the middle is and how much spread is around it.
e. A small part of something may be special in some way and not give an accurate picture of the whole. How much a portion of something can help to estimate what the whole is like depends on how the portion is chosen. There is a danger of choosing only the data that show what is expected by the person doing the choosing.
3. By the end of the 8th grade, students should know that
a. How probability is estimated depends on what is known about the situation. Estimates can be based on data from similar conditions in the past or on the assumption that all the possibilities are known.
b. Probabilities are ratios and can be expressed as fractions, percentages, or odds.
c. The mean, median, and mode tell different things about the middle of a data set.
d. Comparison of data from two groups should involve comparing both their middles and the spreads around them.
e. The larger a well-chosen sample is, the more accurately it is likely to represent the whole. But there are many ways of choosing a sample that can make it unrepresentative of the whole.
f. Events can be described in terms of being more or less likely, impossible, or certain.
1. By the end of the 2nd grade, students should know that
a. People are more likely to believe your ideas if you can give good reasons for them.
2. By the end of the 5th grade, students should know that
a. One way to make sense of something is to think how it is like something more familiar.
b. Reasoning can be distorted by strong feelings.
3. By the end of the 8th grade, students should know that
a. Some aspects of reasoning have fairly rigid rules for what makes sense; other aspects don't. If people have rules that always hold, and good information about a particular situation, then logic can help them to figure out what is true about it. This kind of reasoning requires care in the use of key words such as if, and, not, or, all, and some. Reasoning by similarities can suggest ideas but can't prove them one way or the other.
b. Practical reasoning, such as diagnosing or troubleshooting almost anything, may require many-step, branching logic. Because computers can keep track of complicated logic, as well as a lot of information, they are useful in a lot of problem-solving situations.
c. Sometimes people invent a general rule to explain how something works by summarizing observations. But people tend to overgeneralize, imagining general rules on the basis of only a few observations.
d. People are using incorrect logic when they make a statement such as "If A is true, then B is true; but A isn't true, therefore B isn't true either."
e. A single example can never prove that something is true, but sometimes a single example can prove that something is not true.
f. An analogy has some likenesses to but also some differences from the real thing.
1. By the end of the 8th grade, students should know that
a. The motion of an object is always judged with respect to some other object or point and so the idea of absolute motion or rest is misleading.
b. Telescopes reveal that there are many more stars in the night sky than are evident to the unaided eye, the surface of the moon has many craters and mountains, the sun has dark spots, and Jupiter and some other planets have their own moons.
B. Uniting the Heaven and Earth
1. By the end of the 8th grade, students should know that
a. From the earliest times until now, people have believed that even though millions of different kinds of material seem to exist in the world, most things must be made up of combinations of just a few basic kinds of things. There has not always been agreement, however, on what those basic kinds of things are. One theory long ago was that the basic substances were earth, water, air, and fire. Scientists now know that these are not the basic substances. But the old theory seemed to explain many observations about the world.
b. Today, scientists are still working out the details of what the basic kinds of matter are and of how they combine, or can be made to combine, to make other substances.
c. Experimental and theoretical work done by French scientist Antoine Lavoisier in the decade between the American and French revolutions led to the modern science of chemistry.
d. Lavoisier's work was based on the idea that when materials react with each other many changes can take place but that in every case the total amount of matter afterward is the same as before. He successfully tested the concept of conservation of matter by conducting a series of experiments in which he carefully measured all the substances involved in burning, including the gases used and those given off.
e. Alchemy was chiefly an effort to change base metals like lead into gold and to produce an elixir that would enable people to live forever. It failed to do that or to create much knowledge of how substances react with each other. The more scientific study of chemistry that began in Lavoisier's time has gone far beyond alchemy in understanding reactions and producing new materials.
1. By the end of the 8th grade, students should know that
a. The accidental discovery that minerals containing uranium darken photographic film, as light does, led to the idea of radioactivity.
b. In their laboratory in France, Marie Curie and her husband, Pierre Curie, isolated two new elements that caused most of the radioactivity of the uranium mineral. They named one radium because it gave off powerful, invisible rays, and the other polonium in honor of Madame Curie's country of birth. Marie Curie was the first scientist ever to win the Nobel prize in two different fields--in physics, shared with her husband, and later in chemistry.
1. By the end of the 8th grade, students should know that
a. Throughout history, people have created explanations for disease. Some have held that disease has spiritual causes, but the most persistent biological theory over the centuries was that illness resulted from an imbalance in the body fluids. The introduction of germ theory by Louis Pasteur and others in the 19th century led to the modern belief that many diseases are caused by microorganisms--bacteria, viruses, yeasts, and parasites.
b. Pasteur wanted to find out what causes milk and wine to spoil. He demonstrated that spoilage and fermentation occur when microorganisms enter from the air, multiply rapidly, and produce waste products. After showing that spoilage could be avoided by keeping germs out or by destroying them with heat, he investigated animal diseases and showed that microorganisms were involved. Other investigators later showed that specific kinds of germs caused specific diseases.
c. Pasteur found that infection by disease organisms--germs--caused the body to build up an immunity against subsequent infection by the same organisms. He then demonstrated that it was possible to produce vaccines that would induce the body to build immunity to a disease without actually causing the disease itself.
d. Changes in health practices have resulted from the acceptance of the germ theory disease. Before germ theory, illness was treated by appeals to supernatural powers or by trying to adjust body fluids through induced vomiting, bleeding, or purging. The modern approach emphasizes sanitation, the safe handling of food and water, the pasteurization of milk, quarantine, and aseptic surgical techniques to keep germs out of the body; vaccinations to strengthen the body's immune system against subsequent infection by the same kind of microorganisms; and antibiotics and other chemicals and processes to destroy microorganisms.
e. In medicine, as in other fields of science, discoveries are sometimes made unexpectedly, even by accident. But knowledge and creative insight are usually required to recognize the meaning of the unexpected.
1. By the end of the 8th grade, students should know that
a. Until the 1800s, most manufacturing was done in homes, using small, handmade machines that were powered by muscle, wind, or running water. New machinery and steam engines to drive them made it possible to replace craftsmanship with factories, using fuels to replace human and animal labor. In the factory system, workers, materials, and energy could be brought together efficiently.
b. The invention of the steam engine was at the center of the Industrial Revolution. It converted the chemical energy stored in coal, which was plentiful, into mechanical work. The steam engine was invented to solve the urgent problem of pumping water out of coal mines. As improved by James Watt, it was soon used to move coal, drive manufacturing machinery, and power locomotives, ships, and even first automobiles.
1. By the end of the 2nd grade, students should know that
a. Most things are made of parts.
b. Something may not work if some of its parts are missing.
c. When parts are put together, they can do things that they couldn't do by themselves.
2. By the end of the 5th grade, students should know that
a. In something that consists of many parts, the parts usually influence one another.
b. Something may not work as well (or at all) if a part is missing, broken, worn out, mismatched, or misconnected.
3. By the end of the 8th grade, students should know that
a. A system can include processes as well as things.
b. Thinking about things as systems means looking for how every part relates to others. The output from one part of a system (which can include material, energy, or information) can become the input to other parts. Such feedback can serve to control what goes on in the system as a whole.
c. Any system is usually connected to other systems, both internally and externally. Thus a system may be thought of as containing subsystems and as being a subsystem of a larger system.
1. By the end of the 2nd grade, students should know that
a. Many of the toys children play with are like real things only in some ways. They are not the same size, are missing many details, or are not able to do all of the same things.
b. A model of something is different from the real thing but can be used to learn something about the real thing.
c. One way to describe something is to say how it is like something else.
2. By the end of the 5th grade, students should know that
a. Seeing how a model works after changes are made to it may suggest how the real thing would work if the same were done to it.
b. Geometric figures, number sequences, graphs, diagrams, sketches, number lines, maps, and stories can be used to represent objects, events, and processes in the real world, although such representations can never be exact in every detail.
3. By the end of the 8th grade, students should know that
a. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly, or that are too vast to be changed deliberately, or that are potentially dangerous.
b. Mathematical models can be displayed on a computer and then modified to see what happens.
c. Different models can be used to represent the same thing. What kind of model to use and how complex it should be depends on its purpose. The usefulness of a model may be limited if it is too simple or if it is needlessly complicated. Choosing a useful model is one of the instances in which intuition and creativity come into play in science, mathematics, and engineering.
1. By the end of the 2nd grade, students should know that
a. Things change in some ways and stay the same in some ways.
b. People can keep track of some things, seeing where they come from and where they go.
c. Things can change in different ways, such as size, weight, color, and movement. Some small changes can be detected by taking measurements.
d. Some changes are so slow or so fast that they are hard to see.
2. By the end of the 5th grade, students should know that
a. Some features of things may stay the same even when other features change. Some patterns look the same when they are shifted over, or turned, or reflected, or seen from different directions.
b. Things change in steady, repetitive, or irregular ways--or sometimes in more than one way at the same time. Often the best way to tell which kinds of change are happening is to make a table or graph of measurements.
3. By the end of the 8th grade, students should know that
a. Physical and biological systems tend to change until they become stable and then remain that way unless their surroundings change.
b. A system may stay the same because nothing is happening or because things are happening that exactly counterbalance one another.
c. Many systems contain feedback mechanisms that serve to keep changes within specified limits.
d. Symbolic equations can be used to summarize how the quantity of something changes over time or in response to other changes.
e. Symmetry (or lack of it) may determine properties of many objects, from molecules and crystals to organisms and designed structures.
f. Things that change in cycles, such as the seasons or body temperature, can be described by their cycle length or frequency, what the highest and lowest values are, and when they occur. Different cycles range from many thousands of years down to less than a billionth of a second.
1. By the end of the 2nd grade, students should know that
a. Things in nature and things people make have very different sizes, weights, ages, and speeds.
2. By the end of the 5th grade, students should know that
a. Almost anything has limits on how big or small it can be.
b. Finding out what the biggest and the smallest possible values of something are is often as revealing as knowing what the usual value is.
3. By the end of the 8th grade, students should know that
a. Properties of systems that depend on volume, such as capacity and weight, change out of proportion to properties that depend on area, such as strength or surface processes.
b. As the complexity of any system increases, gaining an understanding of it depends increasingly on summaries, such as averages and ranges, and on descriptions of typical examples of that system.
1. By the end of the 2nd grade, students should
a. Raise questions about the world around them and be willing to seek answers to some of them by making careful observations and trying things out.
2. By the end of the 5th grade, students should
a. Keep records of their investigations and observations and not change the records later.b. Offer reasons for their findings and consider reasons suggested by others.
3. By the end of the 8th grade, students should
a. Know why it is important in science to keep honest, clear, and accurate records.
b. Know that hypotheses are valuable, even if they turn out not to be true, if they lead to fruitful investigations.
c. Know that often different explanations can be given for the same evidence, and it is not always possible to tell which one is correct.
1. By the end of the 2nd grade, students should be able to
a. Use whole numbers and simple, everyday fractions in ordering, counting, identifying, measuring, and describing things and experiences.
b. Readily give the sums and differences of single-digit numbers in familiar contexts where the operation makes sense to them and they can judge the reasonableness of the answer.
c. Give rough estimates of numerical answers to problems before doing them formally.
d. Explain to other students how they go about solving numerical problems.
e. Make quantitative estimates of familiar lengths, weights, and time intervals and check them by measurements.
2. By the end of the 5th grade, students should be able to
a. Add, subtract, multiply, and divide whole numbers mentally, on paper, and with a calculator.
b. Use fractions and decimals, translating when necessary between decimals and commonly encountered fractions--halves, thirds, fourths, fifths, tenths, and hundredths (but not sixths, sevenths, etc.).
c. Judge whether measurements and computations of quantities such as length, area, volume, weight, or time are reasonable in a familiar context by comparing them to typical values.
d. State the purpose of each step in a calculation.
e. Read and follow step-by-step instructions in a calculator or computer manual when learning new procedures.
3. By the end of the 8th grade, students should be able to
a. Find what percentage one number is of another and figure any percentage of any number.
b. Use, interpret, and compare numbers in several equivalent forms such integers, fractions, decimals, and percents.
c. Calculate the circumferences and areas of rectangles, triangles, and circles, and the volumes of rectangular solids.
d. Find the mean and median of a set of data.
e. Estimate distances and travel times from maps and the actual size of objects from scale drawings.
f. Insert instructions into computer spreadsheet cells to program arithmetic calculations.
g. Determine what unit (such as seconds, square inches, or dollars per tankful) an answer should be expressed in from the units of the inputs to the calculation, and be able to convert compound units (such as yen per dollar into dollar per yen, or miles per hour into feet per second).
h. Decide what degree of precision is adequate and round off the result of calculator operations to enough significant figures to reasonably reflect those of the inputs.
i. Express numbers like 100, 1,000, and 1,000,000 as powers of 10.
j. Estimate probabilities of outcomes in familiar situations, on the basis of history or the number of possible outcomes.
1. By the end of the 2nd grade, students should be able to
a. Use hammers, screwdrivers, clamps, rulers, scissors, and hand lenses, and operate ordinary audio equipment.
b. Assemble, describe, take apart and reassemble constructions using interlocking blocks, erector sets, and the like.
c. Make something out of paper, cardboard, wood, plastic, metal, or existing objects that can actually be used to perform a task.
d. Determine the linear dimensions in whole units of objects having straight edges.
2. By the end of the 5th grade, students should be able to
a. Choose appropriate common materials for making simple mechanical constructions and repairing things.
b. Measure and mix dry liquid materials (in the kitchen, garage, or laboratory) in prescribed amounts, exercising reasonable safety.
c. Keep a notebook that describes observations made, carefully distinguishes actual observations from ideas and speculations about what was observed, and is understandable weeks or months later.
d. Use calculators to determine area and volume from linear dimensions, aggregate amounts of air, volume, weight, time, and cost, and find the differences between two quantities of anything.
e. Make safe electrical connections with various plugs, sockets, and terminals.
3. By the end of the 8th grade, students should be able to
a. Use calculators to compare amounts proportionally.
b. Use computers to store and retrieve information in topical, alphabetical, numerical, and key-word files, and create simple files of their own devising.
c. Read analog and digital meters on instruments used to make direct measurements of length, volume, weight, elapsed time, rates, and temperature, and choose appropriate units for reporting various magnitudes.
d. Use cameras and tape recorders for capturing information.
e. Inspect, disassemble, and reassemble simple mechanical devices and describe what the various parts are for; estimate what the effect that making a change in one part of a system is likely to have on the system as a whole.
1. By the end of the 2nd grade, students should be able to
a. Describe and compare things in terms of number, shape, texture, size, weight, color, and motion.
b. Draw pictures that correctly portray at least some features of the thing being described.
2. By the end of the 5th grade, students should be able to
a. Write instruction that others can follow in carrying out a procedure.
b. Make sketches to aid in explaining procedures or ideas.
c. Use numerical data in describing and comparing objects and events.
3. By the end of the 8th grade, students should be able to
a. Organize information in simple tables and graphs and identify relationships they reveal.
b. Read simple tables and graphs produced by others and describe in words what they show.
c. Locate information in reference books, back issues of newspapers and magazines, compact disks, and computer databases.
d. Understand writing that incorporates circle charts, bar and line graphs, two-way data tables, diagrams, and symbols.
e. Find and describe locations on maps with rectangular and polar coordinates.
1. By the end of the 2nd grade, students should
a. Ask "How do you know?" in appropriate situations and attempt reasonable answers when others ask them the same question.
2. By the end of the 5th grade, students should
a. Buttress their statements with facts found in books, articles, and databases, and identify the sources used and expect others to do the same.
b. Recognize when comparisons might not be fair because some conditions are not kept the same.
c. Seek better reasons for believing something than "Everybody knows that . . ." or "I just know" and discount such reasons when given by others.
3. By the end of the 8th grade, students should
a. Question claims based on vague attributions (such as "Leading doctors say . . .") or on statements made by celebrities or others outside the area of their particular expertise.
b. Compare consumer products and consider reasonable personal trade-offs among them on the basis of features, performance, durability, and cost.
c. Be skeptical of arguments based on very small samples of data, biased samples, or samples from which there was no control sample.
d. Be aware that there may be more than one good way to interpret a given set of findings.
e. Notice and criticize the reasoning in arguments in which (1) fact and opinion are intermingled or the conclusions do not follow logically from the evidence given, (2) an analogy is not apt, (3) no mention is made of whether the control groups are very much like the experimental group, or (4) all members of a group (such as teenagers or chemists) are implied to have nearly identical characteristics that differ from those of other groups.