3rd - 8th Grade
Life and Earth Science - Soil characteristics necessary for plant life; Science Inquiry - Observation, properties, variables, and as evidence

Science content focus - what science says - enduring understanding, big ideas, generalizations
Science inquiry focus - how we use science to collect information to understand
Activity sequence
Resources and materials
Pedagogical ideas
Lessons and activities detail



This sequence of activities are to investigate the relationship of soil and plants. Particularly the root system. They also can be used to introduce students to science process of properties, variables, and science investigation. Particularly manipulated and responding variables in a science investigation (see activity water, soil, and roots).


Earth Science - Life science - properties of Earth materials (soil) and how they relate to plants

(what science says - enduring understanding, big ideas, generalizations)

Soil characteristics necessary for plant life.

Related concepts and facts -

  • Earth materials include soil...
  • Soil is composed of sand, silt, clay, rocks, humus (organic matter)
  • Soil can retain water
  • Soil can be compacted
  • Soil has different textures - stickiness, rough, porous,

Outcome - Earth Science -properties of Earth materials (soil) and how they relate to how they relate to plants

Describe how properties of soil - size, texture, mass, shape, stickiness, water retention capacity related to seed germination and plant quality of life.

Specific outcomes - Earth Science - Rock properties and how they relate to how they were made

  1. Describe properties of soil ... - size, texture, mass, shape, stickiness, water retention
  2. Describe a consequence for each soil property - size, texture, mass, shape, stickiness, water retention


Inquiry - Processes - evidence, models, explanations - variables relate to observable changes and variables can be changed (manipulated) by experimenting.

Science investigation are inspired by observation of properties and developed through selection of properties to use as variables (manipulated and responding) to make observations of the repeatable results of those variables interactions.

Related concepts and facts -

  • We use observational evidence and reasoning to explain interactions in our world.
  • We design experiments based on our inferences to better understand our world.
  • Variables are observations of a property or characteristic that changes - size, shape, temperature, amount, volume, rate, ... That can have different values.
  • A hypothesis describes how variables might change under certain situations.
  • Observed changes can be described as changes of properties (variables).
  • When people disagree on an observation, they usually make more and better observations.
  • Observation, creativity, and logical argument are used to explain how variable changes effect resulting observations.
  • Experiments are often created by changing (manipulating) variables (changing properties).
  • The change of one variable (manipulated variable) will interact with another variable (responding variable).
  • A science investigation usually involves identifying properties (characteristics) that might interact with others.
  • A science investigation usually involves selecting a property that can be changed (changing the property makes it a variable).
  • A science investigation usually involves changing the variable (varying a property).
  • Changing the variable as part of a science investigation makes that variable the manipulated variable.
  • The variable that changes because it interacts with the manipulated variable is the responding variable.

Outcome - Inquiry - Processes - evidence, models, explanations -- variables relate to observable changes and variables can be changed (manipulated) by experimenting.

Describe change as a result of interactions. Describe those interactions as changes of a characteristic/ property - variable (manipulated variable) that interacts with another variable (responding variable) (property that changes).

Design a way to manipulate a variable to create a scientific investigation (experiment).

Specific outcomes -

  1. Describe interactions as changes of a characteristic/ property (variable).
  2. Describe how to use observations of one variable (responding variable) to explain how the changes of another variable (manipulated variable) (properties of soil). Larger pieces of soil (clay, sand, gravel) make it harder for the root to penetrate the soil.


to provide sufficient opportunities for students to attain the targeted outcomes.

Possible Activity Sequence

  1. What good is dirt? and Why do plants need dirt?
  2. How can a pipe cleaner model roots in dirt?
  3. Water, soil, and roots. How much water does different kinds of earth materials absorb?
  4. Looking at uprooted seedlings,
  5. Role play plant growth,
  6. Find samples of seeds and tree seedlings,
  7. Why is dirt good for seeds? And What is it about dirt that makes it good for seed growth?
  8. What would the perfect soil do for plants?
  9. Where in nature can we find examples of roots interactions in soil to support or refute what we concluded in our classroom.


Pedagogical ideas

Focus questions - What is the best kind of soil for plants? What is a soil? What are the properties of soil? From what is it made? What are its properties? How does soil effect plants? How is a plant dependent on soil? What are the optimum conditions of soil for different kinds of plants?


Materials:  Soil samples, clay, sand, humus, gravel, rocks, pipe cleaners, coffee filters, containers, water, saplings, hand lenses


Activity 1 - What good is dirt? Why do plants need dirt? Introduction to science inquiry

Instructional procedure

  1. Ask students what is that you are washing off your hands? or Start a discussion with the following questions? What is dirt? What is dirt good for? What would you think about dirt if you were a plant? In what ways is dirt important for plants?
  2. What are some different kinds of soil? (Clay, sandy, gravel or rocky, humus, combinations)
  3. These different characteristics of soil are know to scientist as what? (properties or characteristics)
  4. When a property or characteristic changes it is know as what by scientists? (variable)
  5. How can different soils vary by being made up of different kinds of Earth materials?
  6. What sample soils can we find or can we make? (Clay, sandy, rocky, humus)


Activity 2 Pipe cleaner as model root.

  1. Select three or four different kinds of soil to experiment with.
  2. Show students a pipe cleaner and suggest it might be a fairly good representation of a root.
  3. Tell them they are going to push the pipe cleaner into the different soils and observe what happens.
  4. Ask them what about the soils is different. Ask them what scientist call these differences. Properties or characteristics, and variables. Distinguish between properties (descriptions of observation) and variables (description of how an observable property changes)
  5. How are all the different substances related? (All part of soil)
  6. How do they all vary or cause different soil samples to vary? Different sizes of particles, different masses of particles, shapes of particles, texture of particles, and stickiness of particles.
  7. Decide what four or five kinds of soil to experiment with.
  8. Ask and model how to use the pipe cleaner as a model root.
  9. Experiment, collect date, record it.
  10. Discuses what they found and ask them to suggest how clay, sand, gravel, rocky, and humus vary and might interact with roots.
  11. Bridges - Animated pictures, stories, role play showing how roots penetrate soil; how soil needs to support roots so that the tree, above ground, is supported ; supply water and nutrients...
  12. Exploration - What observations of the pipe cleaner did you make that might relate to plant roots?
    Invention - Identify variables that change how roots interact in soil (pipe cleaner - compaction enough to hold, but also let roots pass) Water retention (how much water does each kind of earth material absorb?)
    Bridges - Observations and reasoning can let us identify variables. Thinking about how the variables change can help identify ideas to try as experiments.
    Discovery, application, extension -

Activity 3 Water, soil, roots.

  1. How do different kinds of soil interact with water?
  2. Select four different kinds of soil (clay, sand, gravel, humus... )
  3. Ask how it might be possible to determine the different kinds of soil might hold or absorb water differently.
  4. Possible procedure. Measure the same volume of each soil 50 ml or the same mass 50 grams (depends on the development of the students - conservation of mass, volume, understanding of each...)
  5. Put each into a container that has holes in the bottom (or a funnel) and a coffee filter inserted to hold the soil materials. Then insert the container into another container that will collect the water that runs through the soil and filter paper.
  6. Decide what variable to measure (mass of soil before the water is added and after) or the volume of water poured over the soil and the amount collected that runs through the soil...
  7. Decide on an amount of water to pour into each (50 ml)
  8. Pour the water, collect the results, and share them with the class.
  9. Discuss the results.
  10. What properties of the different earth materials might explain the differences of how the drained or did not? Size, shape, stickiness....
  11. What does this suggest about how dirt interacts with water, roots, ...
  12. Write a conclusion that suggests how one idea relates to another.

Science investigation discussion -

  1. List or review the lists of properties.
  2. What properties changed during the experiment?
  3. Provide the label - manipulated variable.
  4. What variables changed as a result of those? ....
  5. Provide the label - responding variable.
  6. Show the following framework. The manipulated variable changed this way and the responding variable changes this way. As the size of the soil material increased (from clay, to sand to gravel) the amount of moisture changed from ... As the texture of the soil changed from (clay, sand, to humus) the amount of water that drained changed...
  7. Other...
  8. How do scientists create investigations. (Identify variables to change and see what responds and how.)

Activity 4 What happens to seeds as they are dispersed? How are they dependent on different soils?

  1. Discussion of what would happen to seeds that fell on different soils. Discuss different kinds of plants and what properties would be good for a particular seed to germinate (heat and moisture), young root able to penetrate, seed not likely to rot, roots to penetrate, as well as soil that would provide an optimal amount of water and nutrients.

Activity 5 - Role play seed germinating

  1. The student's role playing seeds falling to the earth, the sun shining, rain wetting the seeds, the seeds laying on dirt, and the seed becoming a seedling.

Activity 6 Looking at different soils outside and the plants that are growing or not growing in them.

  1. Select an area. Test it with a shovel.
  2. Describe the soil and the kinds of roots.
  3. Record the information
  4. Discuss findings
  5. Conclusions

Expansion - An argument could also be made for the artificial soil activity to be part of invention. In that case the expansion could be how do other environments effect other kinds of living objects.

Activity 6 What is the perfect soils for a particular plant?

Identify what might be the best properties for an artificial soil to have for a specific seed or plant.


  1. Select a plant variety and create an artificial soil for its seed or germinated plant.
  2. Planting the seed in the student made artificial soil.
  3. Have students identify what properties the soil should have that they believe would be good for a seed to germinate (heat and moisture), young plant to penetrate, seed not to rot, roots to penetrate, as well as soil that would provide an optimal amount of water and nutrients.



Assessment ideas



Lab Notes

Soils and roots interactions

Kind of soil Observations of properties How the soil interacted with the pipe cleaner (model root)
Combination -    


Outside observations of plants and soil

Location of survey.

Describe the properties of the soil.

Describe the properties of the plant and particularly its root system.

Describe the variables of the soil and roots and what the relationship might be between them.

Site location Properties of the soil Properties of the plant and its root system Relationship and possible cause

How much water do different kinds of soil absorb?

Kind of soil Properties of the soil Amount of water drained through the soil Amount of water absorbed by the soil