Rocks, Minerals, Soil and Fossils Study Guide
What is a rock?
A rock is a naturally formed solid
made up of one or more minerals.
Rocks can have many different colors!
The colors represent the different
minerals that make up the rock.
What is a mineral?
A mineral is a solid object that is formed
in nature and has never been alive. A
mineral is made up of one material and
is the same all the way through. They are
normally the same color all the way
through.
How do I describe rocks and minerals?
What properties do I look for?
1. Color – you can see that different kinds of rocks have different colors. The
colors come from the minerals in the rock. Color is one of the easiest
ways for a scientist to tell minerals apart! They use the streak test.
2. Hardness – Rocks and minerals are different harnesses. Hardness is the
measure of how difficult it is for a mineral to be scratched. We test the
hardness of rocks and minerals using a scratch test. Mohs scale is a tool
scientists use to tell the hardness of a mineral.
3. Luster- the way light interacts with the surface of a
crystal, rock, or mineral
Extra Information
Texture – You can see or feel tiny pieces of minerals in rocks. These pieces
are called grains. A rocks texture is the size and shape of its grains. You can
feel texture. We describe rocks texture as rough or smooth.
Size – rocks and minerals can be ANY size.
Shape – rocks and minerals can be ANY shape.
Types of Soil
Sand
Silt
Clay
Humus
Loam
(Coastal Plain
beaches)
(river)
(can be red or
brown used to
make pottery)
(Georgia marshes)
(mixture of
sand, silt, clay
and humus
found on farms)
Largest Particles
Tiny Particles
Smallest Particles
Tiny grains of
rock that are
too small to
see without a
microscope.
Very, very tiny
grains of rock.
When you rub this
between your
fingers, you
cannot feel the
grains.
Sediment made
up of dead plants
and animals.
Great for
growing plants!
It is dark, holds
water, has lots
of nutrients, and
is made up of
different types
of soils.
Pieces of rocks and
minerals that you
can see with your
eyes.
Does not hold water
well. Isn’t good for
growing because it
does not hold water
well.
Plants that grow in
sand have short
roots that spread out
close to the top of
the ground. Here
they can absorb rain
water quickly.
Gritty
Holds water very
well but isn’t good
for planting
because it holds
too much water. It
is hard for roots to
grow down into
the clay.
Ex. When a leaf
falls from a tree, it
breaks down into
smaller parts and
becomes humus.
(Composting)
Sticky
Rough
Layers of Soil
1. Top soil = has a lot of humus, many small animals (ants, earthworms) live here
2. Subsoil = layer under topsoil that doesn’t have a lot of humus but it does have small rocks
3. Bedrock = layer under subsoil that is made of solid rock, this is where most small rocks in soil
come from
How does water and wind change rocks and soil over time?
Weathering –when wind and rain change the shape of rocks and soils by breaking
them down into smaller pieces (Ancient buildings in Greece)
Examples: Water constantly flowing over a rock for a long period of time; water freezing inside
a tiny crack of a rock and splitting it into two pieces; plants and animals breaking
down a rock
Erosion – the movement of weathered rock and soil (sediment) to a new place
FOSSILS – the hardened remains of a plant or an animal that lived long ago.
Fossils tell scientists about plants and animals that lived on land and in water
long ago.
Scientists can learn information about extinct animals by studying fossils
How are fossils formed?
Some fossils, such as bones and teeth, look like the actual parts of
animals. Slowly, minerals replace the bones.
Other fossils, such as dinosaur tracks in mud, are only marks left
behind. These marks are called trace fossils. The mud hardened, and
in time changed to rock.
A mold is the shape of a once-living thing left in sediment when the rock
formed. The living thing that made the mold breaks down, only leaving a
cavity shaped like the plant or animal..
A cast forms when mud or minerals later fill a mold. The cast has the
actual shape of the living thing. Remember, you made a trace fossil,
mold and model fossil in class.
For a fossil to form an animal must die and be buried by
mud, sand or clay!
S3E1. Students will investigate the physical attributes of rocks and soils.
a.
Explain the difference between a rock and a mineral.
b.
Recognize the physical attributes of rocks and minerals using observation (shape, color, texture), measurement,
and simple tests (hardness).
c.
Use observation to compare the similarities and differences of texture, particle size, and color in top soils (such
as clay, loam or potting soil, and sand.
d.
Determine how water and wind can change rocks and soil over time using observation and research.
S3E2. Students will investigate fossils as evidence of organisms that lived long ago.
a.
Investigate fossils by observing authentic fossils or models of fossils or view information resources
about fossils as evidence of organisms that lived long ago.
b.
Describe how a fossil is formed