Soil and the garden, is it essential? An initial reaction would be to say yes, because when most people think about a garden soil is often associated with it. Like soil though the answere to the question is a complex one.
"Soil is a complex living system composed of living materials, comprising a very thin layer of the Earth. It helps provide plants with the support, nutrients, water, and air necessary for life. Living and non living components interact, change, and combine over thousands of years to create the soil It can take up to 20,000 years to make 2.5cm (one inch) of topsoil."(source)
Fortunately we don't have to make the soil ourselves. soil is being formed
all of the time. It's particles range in size from large (2mm to.05mm) sand
to fine clay particles less than .002mm
The large sand particles allow water and nutrients to drain through it. Clay
particles on the otherhand are very fine and have little pore space. Water and
nutrients move slower and stick to the surface more readily in clay soil. Silt
particles are in between the size of sand and clay.
Activity
Let us fo example that we could make soil. What would be the ingredients of
this mock soil be.
The objective of this activity is to recognize that the outcome of
a final product is determined by it's ingredients and how it is made.
Material:
Real soil samples
student generated materials for making soil. leaves, grass clippings , vegetable
scraps, sand, clay, rocks, shells, egg shells etc.
A variety of muffin recipes.
Students will compare the ingredients in these various recipes.
Some of muffins can be cooked before hand so that a sensory
comparison can be made relating to the ingredients that are contained in the
muffins.
Can we tell from the final product what the ingredients are?
How is our muffin project similar to the making of soil?
How is it different?
Can we compare the different muffin recipes and the different muffins themselves to different soil samples?
What happens to our muffin if certain ingredients, no baking soda are left out or what would happen if we had to much of another ingredient, to much flour, How would it effect the final product?
