Did you know that soil can be divided into layers by some simple science?
Learn some geology and find out what materials compose your soil with this experiment today!
Materials:
A clear jar with lid (glass or plastic), trowel/shovel or something to dig with, access to soil, water, liquid dish soap.
Time Estimated:
10-minute set-up plus wait time
Directions:
In a garden or lawn or somewhere else with accessible dirt or soil, dig down to around 6-8 inches deep
Fill the jar with soil halfway
Add clean water until the jar is about three-quarters full. Add one teaspoon of liquid dish soap and tightly screw the lid on the jar
Shake the jar hard for 3 minutes
Wait for the soil layers to separate
Depending on your soil it may take 20 minutes to even 2 days for the soil to settle
Bonus: Try experimenting with dirt from different areas of your garden, city park, or anywhere else (as long as it is safe and you have permission to do so)!
Think Like A Scientist:
Can you identify the layers of soil?
Which layer is the largest and makes up the most of your soil?
What does the size of your layers tell you about the plants that are growing in it?
Is there anything above the dirt floating in the water layer?
If there aren’t any plants growing around your soil/dirt source, what might that tell you about the healthiness of the soil or dirt?
How It Works:
In today’s activity, you explored the composition of soil! Soil particles are sorted into their own categories and are made up of different minerals and sizes.
The liquid dish soap surrounds each of the soil particles in the jar, allowing them to stay separate and settle at the bottom without bringing along other particles that aren’t the same as them. Over time, the heaviest particles that contain the least amount of water between them fall to the bottom of the jar followed in order by other particles so that they form layers on top of each other. The smallest particles will take the longest to settle as the top layer.
Sand: The largest and heaviest particles which allow larger spaces between particles that water and nutrients can flow out of.
Silt: Particles smaller than clay, but larger than sand.
Clay: The smallest particles that fit the tightest together, causing water and nutrients to flow through
Stuff floating in or on top of the water layer: This is organic matter, meaning that it came from living things and is decaying which releases nutrients into the soil. Examples are dead leaves, bugs, and sticks.
The best soil is called “loamy” which is about 40% sand, 40% silt, and 20% clay. This composition allows for the soil to hold the right amount of water for the plants to use. Soil that has too much sand drains water too quickly which prevents plant roots from absorbing enough to support their growth. Soil that has too much clay holds too much water and expands to squeeze plant roots which prevent the roots from getting air and moving around to grow; this can cause the plant roots to rot and die.
If you tried using dirt where no plants were growing, this tells you that it is low in nutrients or has too much of one type of particle and cannot support the growth of plants. This means nutrients and perhaps additional soil needs to be added to make it easier for plants to grow there. This is how adding compost to soil helps keep plants healthy!
Looking for more fun at home STEM activities for your young scientist? Check out our workbook full of exciting science experiments and empowering activities!
