Download Soil

Soil
TEK
1.7: Earth and space. The student knows that the natural world includes rocks,
soil, and water that can be observed in cycles, patterns, and systems.
The student is expected to:
A: observe, compare, describe, and sort components of soil by size, texture, and
color.
What term do scientist have for dirt?
• It looks like this boy
is making a mess in
the dirt. A scientist
would say that he is
playing in the soil.
• Scientists call dirt
soil.
Who needs soil?
• Soil is one of the
most important
things on our planet.
• It is important for
plants.
• It is important for
animals.
• And it is important
for you.
What is soil?
• Soil is a mix of clay, bits of rock, and
humus.
What is humus?
• Humus is tiny bits of plants and animals
that were once alive.
How is soil formed?
• First tiny bits of rock break off from bigger
rocks. These tiny bits are the start of dirt.
How is soil formed?
• The bits of rock
mix with moss and
dead leaves. Dust
from the air mixes
in, too.
How is soil formed?
• When animals die, their bodies break
down and are added to the mix.
How long does it take for soil to form?
• It takes over 100 years to make one inch
of soil.
Are all soils alike?
• Sandy soil has little humus. It does not
hold water well. Cactus roots can take in
water quickly. Cactus stems are able to
store the water.
Are all soils alike?
• Clay holds a lot of water. Too much clay
in soil is not good. The clay gets hard and
dry in hot weather. It packs together so
roots can’t grow.
Are all soils alike?
• Roses need soil with lots of humus.
Humus is what makes a soil dark. Humus
has the nutrients that plants need to grow.
Most plants grow well in humus.
What is the work of soil?
• Soil helps hold the roots of all plants in
place. The roots of plants take in water
from the soil. They also take in nutrients
from the soil.
Who needs soil?
•
•
•
•
Look that stuff on your shoes. It is important.
It is important for plants.
It is important for animals.
And it is important for you!