1. What Are Some Types of Soil?
Third Grade

2. Humus
The part of soil made up of broken down pieces of dead plants and animals

3. Soil with grains of rock that you can see with your eyes alone.
Sand
Soil with grains of rock that you can see with your eyes alone.

4. Silt
Soil with grains of rock that are too small to be seen with your eyes alone.

5. Clay Soil with very, very tiny grains of rock.
(has smallest grain of rock)

6. The main difference between sand, silt, and clay soils is their grain size. They are also made up of different minerals.
Smallest to largest rock particles. clay, silt, sand

7. Loam Soil that is a mixture of humus, sand, silt, and clay.
Most soils found on farms are loam.

8. Soil Layers
Topsoil
Subsoil
Bedrock

9. Topsoil
Topsoil has a lot of humus. Many small animals, such as ants and earthworms, live in topsoil

10. Subsoil
The layer underneath topsoil. Subsoil does not have a lot of humus, but it does have small rocks in it.

11. Bedrock If you dig deep enough into the soil, you will reach solid rock. This solid rock is called bedrock. Most small rocks in soil come from the bedrock underneath it.

12. All soils have water, humus, air, and small pieces of rock.

13. Soils are different by colors, textures, rock sizes, and different abilities to hold water.

14. How Do Rocks and Soil Change?

15. The breaking down of rocks into smaller pieces.
Weathering
The breaking down of rocks into smaller pieces.
Example: rocks splitting

16. The movement of weathered rock and soil.
Erosion
The movement of weathered rock and soil.

17. Examples of erosion A river carries soil away.
Wind blows sand from a sand dune.
The ocean knocks over a sand castle.