September 2006
Naomi J. Marty
GK-12 Program
Concept:
Earth Science: The Structure of the Earth
Materials:
o Construction paper (red, orange, yellow, brown, grey)
o Compass
o Metric Rulers
o Sand
o Glue sticks, Liquid glue
o Scissors
State Standards:
(arkedu.state.ar.us)
ESS.8.6.1
Identify and diagram the layers of the Earth:
 crust
 mantle
 inner and outer core
ESS.8.6.2
Model the layers of the Earth
ESS.8.6.3
Model how convection currents in the mantle affect lithosphere movement
Procedure
1. Using pictorial representations in a powerpoint presentation, present the earth
as divided into three layers—the crust, mantle, and core—based on
composition and physical properties. Compare the size and density of the
core of the Earth to Mars. Have the students fill out a diagram sheets for
themselves, labeling the layers and major properties.
2. Further dissect the Earth into five layers—the lithosphere, asthenosphere,
mesophere, outer core, and inner core. Describe each layers physical
properties. Compare temperatures to those on the surface of the sun.
Relate prefixes for easier remembering.
3. Explain how scientists mapped the inside of the Earth. Briefly explain how
seismic waves travel more quickly through liquid than solid, so that
seismologists could measure the difference in the arrival times of seismic
waves and calculate the density and thickness of each layer of the earth.
Could have students calculate how long it would take for scientists to
measure a seismic wave produced on the other side of the planet
(lithosphere 7-8 km/sec, asthenosphere 7-11 km/sec, mesosphere 11-13
km/sec, outer core 7-10 km/sec, inner core 11-12 km/sec).
4. Have the students build a scaled model of the layers of the Earth with
construction paper and label each layer and whether it is liquid or solid.
5. While the students are working on their models, prepare a demonstration to
show the process of convection. Discuss what the term convection means
and show the students a demonstration of colored water moving due to
convection.
Convection Model
You will need ice, a hot plate, set of food coloring droppers, a large glass
beaker (6 inches deep and 12 inches in diameter) and tap water. Warm
the hot plate and fill the large glass beaker with lukewarm tap water.
Gather the students, as this demonstration goes pretty quickly. Place the
beaker on the hot plate and add several ice cubes to one side of the glass
beaker. (They should all be floating together.) Add a drop of food coloring
next to the ice. The food coloring should rush down with the melting ice
water and hit the bottom of the beaker, slide across the bottom and, as it
gets warm, rise back up. Because the ice is only on one side, the food
coloring should start to circle around. At this point add a different color of
food coloring and watch its progression like the first drop. Do this with the
next two colors. I like the neon food colors in the order of purple, green,
pink, then blue. By the end of this process the water will probably start to
get muddled in color and you may not be able to see the flow anymore,
but while the colors are fresh it is pretty easy to see the way the water is
moving past the heat/cold sources.
Reflection:
1. What worked?
It was good for the students to label each layer on their model and the
convection model was great, but for everything we needed to repeat the
information and go through a questioning session before the students seemed
confident with their answers to questions about either concept.
2. What didn’t work?
The compasses did not work. I couldn’t even get the compasses to work.
We used patterns after we figured out that the compasses were not working well
enough. We did not have enough time for the conversion calculations (not that
they were too difficult), but I did explain how I did the calculations to scale down
the model of the Earth.
3. What would I change for the next time?
I would not let the kids use compasses.