1. Soils, Erosion and Weathering Review
Summit Hill Elementary
3rd Grade Science Unit

2. (top layer - contains Humus)
Layers of Soil
Name the Layers:
Topsoil
(top layer - contains Humus)
Subsoil
Bedrock
Soil is made of :
water , air, humus,
tiny bits of rock

3. What are the Types of Soil?
Clay
Silt
Loam
Sand
There are more than 70,000 types of soil

4. Is Georgia Red Clay Soil?
Yes! Clay is made of teeny, tiny bits of smooth rock.
You can’t feel the rock pieces and you need a microscope to see them! What DOES it feel like?
Clay feels like smooth, powdery flour

5. What is a good material for making pots?
Clay!
But why?
Clay is sticky and holds water well.
Clay becomes very hard when dry.

6. What is Silt? Silt is made up of tiny bits of rock.
It feels silky smooth and slimy when it’s wet.
Silt is easily carried downstream in a river and deposited on the banks or delta

7. What is Sand? Sand is small bits of grainy rock.
Sand lets water run
right through it!
Sand is small bits of grainy rock.
Sand feels grainy and rough.
You can see small bits of rock with your eyes alone

8. Humus is PART of the top layer of soil.
What is Humus?
Humus is PART of the top layer of soil.
Humus contains:
Dead leaves
Broken down parts of
plants and dead bugs
Animal droppings like worm poop
Humus is euwwwww!

9. Loam is very good for growing plants !
What is Loam?
Loam is a mix of Clay Humus Silt Sand LOAM lets just enough water run through and keeps enough for plants
Loam is very good for growing plants !

10. Which soil requires more fertilizer, sand or loam?
Sand lacks humus found in loam.
Sand! But why?

11. What do plants get from soil?
Minerals, air, water and other organic matter.

12. How is water helpful for topsoil?
Water provides nutrients for the plants and animals that live in the topsoil.

13. Can water be harmful to topsoil?
Yes! But how?
Too much water can cause flooding and erosion of the topsoil.
Erosion in a wheat field.

14. is the process where wind
How Do Rocks Change?
WEATHERING
is the process where wind
and water
BREAK DOWN ROCKS
into smaller pieces.

15. of rocks and soil from one area to another.
How Does Soil Change?
EROSION is the
MOVEMENT
of rocks and soil from one area to another.

16. What causes erosion?
Water
Wind
Landslides
Creep
Glaciers

17. Wind Erosion Examples of moving sand and soil:
The Dust Bowl of 1936 and sand dunes

18. Soil Erosion on Hills LANDSLIDE!
Gravity pulls soil, rocks and plants down the hillsides. Nothing is left to hold the soil in place

19. Water causes the most erosion

20. How can we STOP Erosion?
Use rocks and plants like shrubs, grass and trees to keep the soil in place
Add retaining walls
Put up “keep off” signs near fragile areas.

21. There you have it! The scoop on dirt!