Rocks, Minerals and
Soil
Third Grade
Earth Science
What are rocks?
• Rocks are solid
materials that
are made of one
or more
minerals.
3 Types of rocks
1. Sedimentary
2. Igneous
3. Metamorphic
Metamorphic Rock
•Metamorphic
rock is rocks
that have been
changed by heat
and pressure.
Metamorphic Rocks
Sedimentary Rock
• Sedimentary rocks form when
materials settle into layers and
harden.
• Any rock can become
sedimentary if at the surface.
Igneous Rock
• Igneous rock is a rock
that was once melted
but has cooled and
hardened.
• Hot lava comes out
from within the earth
and is an igneous rock
once cooled.
4 ways to identify rocks
1.
2.
3.
4.
Texture
Color
Size
Hardness
EXPERIMENT TIME!!!
• You are all now junior
geologist. A geologist is
someone who studies
the Earth. We will test
the hardness of rocks
using Moh’s scale.
Moh’s Hardness Scale
• With your group, test the
hardness of rocks and give it a
score of 1 to 10.
• Soft: scratches with fingernail
1 or 2
• Medium/Soft: scratches with
a penny 3 or 4
• Medium/Hard: scratches with
a nail 5 or 6
• Hard: will not scratch 7 or 8
Moh’s Scale
• Working as a group, make a bar
graph with your group rating your
rocks from softest to hardest. Be
sure your graph is labeled and
colorful.
Classify rocks
•
1.
2.
3.
4.
As a group, discuss classifications of your rocks. Remember
the 4 ways to classify rocks.
Color
Size
Texture
Hardness
What are minerals?
• Minerals are
solid natural
made objects
that have never
been alive.
Minerals can be
rock-like or
metals.
How are rocks and minerals different?
• Rocks are made up of
minerals. Minerals are
within all rocks. The
minerals in rocks are
what makes rocks look
different from other
rocks.
Rocks and Mineral
Minerals
Rocks
Usually very pretty
Not pretty
Has a shape
No shape
May contain crystals
No crystals
Will not contain fossils
May contain fossils
Color is mostly the same May have many colors
Identify the Minerals
Time to Play a Game…. How many minerals can you find in the
kitchen? (click on refrigerator)
Types of Soil
1. Clay
2. Sandy soil
3. Potting soil
4. Loam
Clay
• Clay is smooth when
dry and sticky when
wet. Soils high in clay
content are called
heavy soils. Clay also
can hold a lot of
nutrients, but doesn't
let air and water
through it well.
Sandy Soil
• When you rub
sand, it feels
rough. This is
because it has
sharp edges. Sand
doesn't hold many
nutrients.
Loam
• Loam is a mixture of
different types of
soils. Loam soils feel
smooth and spongy
when rolled into a
ball.
Potting Soil
• Potting soil is soil
mixture made for
use in gardens and
potted plants.
Potting soil should
be loose and light.
What are fossils?
• A fossil is a mark
or the remains
of something
that was once
living.
4 Types of Fossils
1. Mold
2. Cast
3. Trace
4. True-form
Mold Fossil
• A mold fossil is a
impression made in a
substance. It is not
the actual living
organism but a
impression.
• The picture is a mold
fossil of a leaf.
Cast Fossil
• A cast fossil is
formed when a
mold fossil is filled
in. The fossil can be
of anything that
once lived (plants,
animals, insects).
Trace Fossil
• Trace fossils are
impressions like mold
fossils but are not the
actual living organismjust evidence of them.
• Examples: nests,
burrows, and footprints.
True-Form Fossils
• True form fossils are
the actual once living
animal or organism.
• Example: Animal
bones