Gas laws Boyle's law relates the pressure of gas to its volume at a constant temperature. Charles Law relates the volume to the temperature. The ideal gas law relates the state of a gas is to its pressure, volume, and temperature.
Density relates mass and volume. D = m/v
Theory in science is a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypothesis, National Academy of Sciences (1999).
Science theories are systems of explanations that have been created from substantiated repeated observations and through reasoning. Theories can NOT be directly tested. That means theories contain non observable objects or ideas that can NOT be observed. Only indirect evidence can be used to support them and establish their validity. The more indirect evidence collected the greater the confidence in a theory.
Examples of Theories: states of matter, chemical change, evolution, kinetic molecular theory, heat and energy transfer. Kinetic molecular theory is an inferred explanation of Boyle's law. Bohr's model of the atom with orbits of energy levels. Classification theory.
Theories and laws are different kinds of knowledge and one does not become the other. Theories can never acquire the status of "law" since they can never be directly tested and are only supported by indirect evidence and reasoning. Scientific laws do not have a higher status than a theory. Bohr's atomic model and the idea of species are functional theoretical models rather than reality.
Theories go beyond observations. They are made of concepts that are in accordance with common observation or go beyond and propose new explanatory models for the world.
Laws describe something in nature. A theory is an attempt to explain why nature is the way it is. Theories set a framework of a general explanation upon which specific hypotheses are developed. Since theories have things that cannot be observed we deduce consequences from them that could be tested.
Scientists are human. Like all people they interpret the same data sets differently because they use different life experiences and different ways of thinking. Science never starts with neutral observations. Observations are always guided by questions or problems which are created by an individual or collective theoretical perspective. The lack of a scientist being able to communicate or know what theoretical perspectives influences ones questions or problem creations doesn't mean scientists do not have or are not using any. Theoretical perspectives are embedded in the different aspects of ones culture: society, economics, politics, philosophy, and religion.
Culture shapes science beyond what is investigated
Some cultures believe only humans have a spirit or soul, others believe all living things have them, and still others believe even nonliving things do. That surely effects the way a person attributes cause and effect explanations.
After the discovery of hormones effects and possible use for birth control, Gregory Pincus persuaded Dr. John Rock to administer the hormone progesterone for 21 days, followed by a 7-day break. They did so because they knew the Pill would be controversial (perspective - cultural) and wanted it to be seen as a natural process, not something that interferes with the normal menstrual cycle. This strategy worked with the FDA approving the use of the pill for menstrual cycle control in 1957 and three years later for contraception. Rock, catholic, hoped this strategy would cause greater acceptance with the Catholic Church, however the Pope didn't agree.
Biologically there was no reason to constrain administration of the hormone to this time scale. Any time scale could have been used. Now there are pills given for three months daily before a seven day break and also daily pills without any break.
The law of gravity can be calculated by any culture that has a well defined and accurate calculation of time, which we take for granted. We forget how recent it has been that we established ways of determining time accurately to hours, minutes, seconds, and smaller. Along with this technology there must also be cultural acceptance for its use to collect sufficient data to lead to laws and theories for gravity.
Einstein referred to gravity and it's interaction with objects as visualizing a large rubber sheet with objects as proportional masses sinking into the rubber. The gravitational effect on the objects movements through space could be visualized as the different massed objects rolling across the rubber sheet. Each object's motion being changed depending on the indents of all the objects near to where the moving object is rolling. The depth of indents caused by both object's masses. This analogy can only be created or understood in a culture that had experience with sheets and rubber and spheres.
We are so acclimated to our culture it is almost impossible to step outside it.
Scientific knowledge can be reliable and durable, but it is never absolute or certain. All of its knowledge including facts, theories, and laws are subject to change. Change as new evidence is available. Nothing is ever absolutely "proven". It is impossible to test every possible instance or to even be aware of what they or the future might be. If an idea could be "absolute" or "proven", then how much knowledge would need to be collected before it could be claimed "absolute" or "proven"? How many experiments would need to be done? Logically for something to be certain or true not one single occurrence can violate the explanation. This would include every past, present, and future instance, of which we have no knowledge. Since, future events, at least are not provable, there is no information that can have absolute "proven" status. No law, hypothesis, or theory.
Take the idea of what constitutes a species. A set of organisms that interbreed and produce fertile offspring. Even this information becomes clouded and can't always be used to distinguish species. Some organisms are asexual. Some of which have differences between organisms that are so wide it is difficult to determine where differences between organisms stop and differences between species begins. Another example is the acceptance of wolves in a species separate from dogs. Yet these two species are able to interbreed successfully. Even less clear are the distinctions between subspecies?
Further, species is a category that is decided by the definition people give to it. While the idea of a species breeding with only itself is common as a distinction it doesn't always hold up. Different species - polar bear and brown/grizzly bear can have hybrid offspring. As well a mule is a hybrid offspring of a female horse and a male donkey, yes the other way around is a hinny, many plant hybrids have also been created by cross breeding of different species and these hybrids can't reproduce.
Yes we could use a blood test or DNA test to compare a sample from a known species to a sample from an unknown species. In some cases there will be evidence to strongly support one species classification over all others. However, take the hybrid examples for the mule and Polar/Brown bear. When the testing is done and you know the parents are of two different species, then in which species do you put the offspring? Huh?
It is a human decision that can be claimed - arbitrary. Not determined by the evidence one way or another. How can a person be sure that the line between two species is drawn accurately? Could it not be moved a little closer one way or another and still make sense? Does it really matter if we ever agree exactly where? Should a mule be in the species horse, or donkey, or a species by it self? Whoa! (pun intended) If you're thinking by it self, remember we started with the definition of a species being able to reproduce with its own kind, then a mule can't have their own species. So would you put the hinny and the mule in the same species? What if each would resemble a different species (donkey or horse) more because of the sex differences of parents?
So it seems we are backed into a corner. What is the problem and is there a solution? The problem is to recognize that classification is arbitrary and the selection of category definitions limits what is placed within each category. Again these are based on human decisions as to what constitutes a separation between categories. In this case the definition of species is to determine categories and the separation of living things into those categories, for which the categories do not precisely fit the real world observations. In fact it could be argued there is no fit because of all the diversity among living organisms on Earth. So because our need to classify may be part of our human nature, we tend to do it. And from that tendency we find having a classification system is helpful in thinking and communicating scientifically. However, we must be careful to recognize its limits and use it as it has value.
Science strives to ask questions and is fueled by a desire to answer those questions and with the acceptance of science as not absolute, opens the door to continual expansion of understanding. This creation of understanding requires a very creative and imaginative process to create a wealth of possible questions to pursue and plausible explanations for data collected in the pursuit of understanding.