Soil Concepts

Rock Cycle Review

Weathering and erosion Solidification Melting Heat and pressure Weathering and erosion Compacting Melting Weathering and erosion Heat and pressure

Review from yesterday What are the 3 steps involving sediments? Weathering Breaking to small pieces Erosion: Moving small pieces Sedimentation: Dropping off the small pieces

Skittle Art

Explain specifically how putting water on the skittle simulated these 3 steps. The weathering occurred when we poured water on the Skittle and it broke off little pieces. The erosion occurred when we tilted the plate to move the coloured water. The sedimentation occurred when the small pieces were dropped off somewhere else (the middle of the plate).

What is soil?

What is soil? Soil is a mixture of particles of different size that have been weathered and eroded. It is also made up of minerals and decomposed organic matter

Soil profiles Scientists always study soil by digging a hole and looking at soil from the side. This side view is called a soil profile. Soil profiles have visible layers. These layers are called horizons.

What can you find in each horizon? Topsoil: Living things and detritus

What can you find in each horizon? Topsoil: Living things and detritus Horizon A: Humus (organic matter in soil), a few crumbled rocks

What can you find in each horizon? Topsoil: Living things and detritus Horizon A: Humus, a few crumbled rocks Horizon B: Crumbled rocks, some humus

What can you find in each horizon? Topsoil: Living things and detritus Horizon A: Humus, a few crumbled rocks Horizon B: Crumbled rocks, some humus Horizon C (subsoil): Big rocks Bedrock

Soil texture Soil is a mixture of 3 different particles: Sand Silt Clay

What is the difference between these different particles? Sand: the largest particle, very porous (air pockets) Silt: medium sized particle, less porous Clay: smallest particle, not porous

Soil up close

Which type of soil is the most porous?

Why can’t you grow plants at the beach? Water runs through sand too quickly, because its particles are larger.

This is a wetland. What type of soil do you expect? Why? Water pools on top of the clay-rich soil because water cannot move through clay easily. Its particles are too small.

What about our soil? Our soil is rich in silt and clay. It’s also rich in organic matter. Our soil is some of the most fertile in the world.

How do we know?

How do we know?

Soil Demo