Video Transcript
Clay is one type of soil. What is clay soil composed of? (A) Mainly clay particles. (B) Silt particles. (C) Humus. (D) A small amount of sand
particles. (E) All of the answers are
correct.
To answer the question, we need to
identify all the components in clay soil. It might make sense to think that
clay soil is made only of clay particles. But soils are mixtures of different
particles. We can show that soils are mixtures
by mixing a soil sample with water. As we can see from the diagram,
this causes the different particles in the soil to separate out into layers. So, we know that clay soil, like
other soils, is a mixture. But what is it a mixture of?
Unsurprisingly, the first type of
particle we find in clay soil is clay particles. Clay particles are the smallest
type of soil particle. Clay soil is mainly made of clay
particles. The second type of particle we find
in clay soil is silt particles. Silt particles are larger than clay
particles. But there are not as many silt
particles in clay soil as there are clay particles.
Clay soil also contains humus. Humus is dead and decaying plants
and animals, also known as organic matter. It helps make soil fertile. Clay soils usually only have a
small amount of humus in them. Lastly, clay soils also contain
sand particles. Sand particles are larger than clay
and silt particles. There is only a small amount of
sand in clay soil.
So, we can see that clay soil is a
mixture of mainly clay particles, some silt particles, and a small amount of humus
and sand particles. So, the correct answer is “all of
the answers are correct.”
