The Layers of the Earth
Activity: Book based earth science
Grade Level: 2nd
Introduction:
The Earth is a round planet. From space the Earth looks like a ball. We can only
see the outside of this ball. But, there are objects inside the Earth that we cannot see.
These objects inside are stacked on top of each other. These stacks are called layers. The
layers are made of rock. But, the layers are not the same and they have been given
different names. The layer we stand on is called the crust. The crust is actually the
smallest layer. The layer under the crust is the mantle. The mantle is made of magma.
Magma is the hot rock that comes out of volcanoes. The next layer underneath the
mantle is the core. The core is the center of the Earth. The core is made of very hot solid
rock.
The crust of the Earth actually moves. The crust is divided into pieces like a
puzzle. The puzzle fits together really tight. But, sometimes the mantle underneath the
crust moves. When the mantle moves it causes the pieces of the crust move. When the
crust moves, it can build a mountain, cause an earthquake, or form a big crack in the
Earth. A mountain can be formed when one piece of the crust slides over top of another.
An earthquake happens when the pieces of the crust slide sideways in different directions.
A big crack happens when two pieces of the crust move apart.
Purpose:
This lab will introduce students to the layers of the Earth. The lab will also show
what happens when the crust moves.
Equipment and Materials:
plastic bowl
2 pieces of cardboard
hand soap
aluminum foil
marble
plastic wrap
Safety:

Never eat or drink in the lab
Procedure:
The Layers of the Earth
1. The marble is the Earth’s core. Put it is the bottom of the bowl.
2. The hand soap is the Earth’s mantle. Completely cover the marble with soap.
3. Wrap 1 piece of cardboard in aluminum foil. Put this piece on top of the soap.
This will be the land crust.
4. Wrap the other piece of cardboard in plastic wrap. Put this piece beside the other
one on top of the soap. This piece will be the ocean crust.
5. Describe what you see.
Movement of the Crust
1. Take the land crust and push it over top of the ocean crust.
What will this movement form?
A. a mountain
B. an earthquake
C. a big crack
Why did you choose that answer?
2. Let the crusts go back to the way they were.
3. Take the crusts and move them sideways. Was this easy to do? Yes of No?
What will this movement cause?
A. a mountain
B. an earthquake
C. a big crack
Why did you choose this answer?
4. Let the pieces go back the way they were
5. Take the crusts and move them apart.
What will the movement form?
A. mountain
B. earthquake
C. big crack
Why did you choose your answer?
6. Let the pieces go back the way they were.
Questions:
1. Look at the model you made. Which layer of the Earth is the thickest?
How can you tell?
2. Was it easy to make a big crack? Why?
Teacher’s Notes
The Layers of the Earth
Lab time: 25 minutes
Preparations:
Time: 10 minutes
T: The cardboard should have very crooked edges. This is to be more realistic. It
will also require more force to create the earthquake. Also keep the pieces
small enough so they can move freely in the bowl. Don’t let them get too big.
T: The cardboard is wrapped in aluminum foil and plastic wrap to enhance the
visual stimulation. It will work best if the students crumple the aluminum foil
slightly. It will give them something to hold onto plus it will look more like
land. If the foil can some how be made green, it will represent the land even
better. Magic markers might work for the green alteration. Also, Reynolds
Wrap now offers a Crystal Blue color of plastic wrap. If this plastic wrap is
available, it is recommended for use. It is an easy way to make the ocean look
blue.
T: Hand soap is used to represent the mantle. It was chosen because of its
consistency. It moves very close to what the real mantle would.
T: Actual thicknesses and compositions.
Crust: averages 25 miles thick. It is composed of Basalt and Granite.
Basalt is a very dark green to black rock. The grains of the rock are
very fine. It is classified as a volcanic rock, which means that the rock
was originally part of the volcano magma. The rock then cooled and
solidified.
Granite is a multi-colored rock. It is made up of a combination of
other minerals. These minerals are feldspar, an orange colored rock, and
quartz, a clear rock that is very hard. The grains of granite are very
course. Granite is classified as an igneous rock, which means that the
minerals in the rock were pushed together under a very high amount of
pressure.
Mantle: about 1800 miles thick. But temperatures in the mantle can reach as
high as 4000oF. These high temperatures do not let the rock from and
solidify. The mantle tends to shift and flow at a moderately slow rate.
This makes the mantle appear to creep like really hot plastic would. This
creep is responsible for the movement of the plates of the crust.
Core: about 2150 miles thick. Composed of Iron and Nickel.
The core is actually broken down into the inner and outer core. The
outer core is about 1350 miles thick. Temperatures in the outer core are
not as high as in the mantle, so the rock is molten instead of liquefied.
Molten is a step in between solid and liquid. It is a combination of the two
states.
The inner core is about 800 miles thick. It is make up of solid Iron and
Nickel. For the purpose of keeping things simple, the inner and outer core
were put together in this lab.
T: The crust varies in thickness. The deepest point we can measure is the Mariana
Trench in the Pacific Ocean. It reaches a depth of 36,198 feet, which is 6.86
miles. The highest point is Mount Everest. It measures at a height of 29,028
feet, which is 5.50 miles.
T: The crust of the Earth moves in three different directions. These different
movements create three different land changes that are visible on the Earth’s
crust. One way the crust can move is by sliding the land crust over the ocean
crust. This movement will push the land crust higher and create a mountain.
A second movement type is when two pieces of the crust grip and slip.
The crusts are trying to move from North to South, or vise versa and run into
the jagged edges of other plates. The pressure will build up until the plates
actually slide apart. The slide results in an earthquake.
The third type of movement is when the pieces of the crust move away
from each other. The movement creates a trench or really deep crack in the
crust.
V: The van can supply the needed materials upon request.
Ways to teach this lab:
Here are a few suggestions that might help clarify the fact that the Earth has
layers and that the crust moves. It will also help the students realize what each type of
crust movement will create.
Start off by introducing the different layers of the Earth. It will probably be best
to work from the crust down to the core. Draw a picture of the Earth on the board and
put the three layers in place as they are described. The drawing can be of a wedge shape,
a ball, or both at the same time. The actual mileage is hard to comprehend for the
students, but try to draw the sketches in relative proportions.
To describe the movement of the crust, have the students stand in two different
lines that face each other and hold hands. It will look a lot like you are getting ready to
play Red Rover, but have the lines relatively close together. One line will represent the
land crust and one will represent the ocean crust. Now have both lines step back about
two steps away from the center. Have them look at the floor and realize the large
distance that is now between them. The students have now created a trench, or what is
referred to in the lab as a big crack.
Now have the lines come back to the original starting places. Have them drop
their hands, but stay close together by rubbing shoulders. Have both lines put their hands
out into the space between the lines. Then have the hands of the land crust slide over top
of the hands belonging to the ocean crust. You have now created a mountain.
The third movement is the earthquake. Have the students put their hands straight
out into the empty space again, still with the shoulders rubbing together, but this time
have the knuckles closest to the wrist rub together, see picture below. Thus, both plates
are connected. Now have the land crust move their hands towards their thumb and the
ocean crust move their hands towards their pinky finger. Just one knuckle over is all that
is needed. Make sure both students are pushing on each other. This will create more
friction and consequently need more force.
End result
Land
Ocean
Have the students sit down at their desks again and start to pass out the needed
materials. Hand out one step at a time.
Answers to Questions:
The multiple choice questions in the lab.
1 is A, the mountain. 2 is B, the earthquake. 3 is C, the big crack.
1
Look at the model you made. Which layer of the Earth is the biggest?
The mantle
How can you tell?
It is the thickest layer in the model
2
Was it easy to make a big crack? Why?
Yes, You did not have to fight the parts of the other crust. The crusts move
apart without touching each other.
Considerations:
Another way to produce visual stimulation is through using an apple or a peach.
If you cut these fruits vertically, they give a great representation of what the Earth looks
like if it could be cut. The skin represents the crust, the pulp or part we eat is the mantle
and the seeds are the core. These fruits are nice as well because their proportions are
almost exactly like the layers of the Earth.
This lab can also be done with a large Styrofoam ball. A section of the ball can
be cut away, and the students can color in the layers. The crust movements are slightly
harder to do in this situation. One way to demonstrate the movement here would be to
lay the wrapped cardboard pieces on top of the ball to represent the crust and move them
to create the different movements of the crust.
One other way to show the movement of the crust is through a puzzle. The
puzzles with really small pieces that don’t stay together very well will work the best. To
show the crust movements, have a section of the puzzle already put together. A straight
edge will work nicely. Then have the students push both corners together, the puzzle will
fold onto itself and create a mountain.
To represent a trench, have students gently pull the puzzle apart. It will break and
the pieces will move apart. The earthquake can be represented by putting the hook and
eye sides of the puzzle together and then try to move them one side a North to South
direction and the other in a South to north direction. The pieces will cause enough
resistance to resemble the force needed to cause an earthquake.