7th Grade Integrated Science
name____________________
Title: Scale Model of Earth
Introduction: Earth is not just a ball of rock. It is a complex, layered ball of
rock. Earthquake waves traveling through Earth do not pass straight through.
They bounce off of layers composed of different materials with different densities,
states and composition. Scientists measure earthquake waves and have made
models of what they think is inside Earth. In this activity, you will make a scale
model of Earth and see the layers and features of the crust in their true
proportions.
Materials:
1.5 x 1.5 piece of butcher paper, 1 meter string, metric rulers, markers.
Procedures:
1. To make a scale model, every part of the object being modeled needs to be
“shrunk” mathematically. This is done by dividing every part by the same
number. To make our model, the shrinking factor is 1: 60,000,000. Earth will be
60 million times smaller in our model than in real life. In the metric system, our
conversion factor will be 60 km on Earth = 1 cm on our model.
2. Start by dividing the numbers of the real Earth on the data table below by 60.
Put that number in the column for thickness on the model.
3. Find the center of your large piece of paper. Put a dot there. Tie a pencil to
your string. Measure the thickness you calculated for the inner core on your
paper, starting from the dot. Use the string like a compass and hold it on the
center and rotate the pencil in a circle the correct size around it.
4. Continue making circles; remember to draw each time from the center but add
the thickness of each layer to the layer before it.
5. Add the surface features last.
6. When you are done, label each layer by name and write it’s density, phase
and composition on it.
7. Answer the analysis questions when you are done.
Data:
Layers of Earth
Earth Layer
Inner core
Outer core
Mantle
Crust
Real thickness (km)
1255
2220
2895
40
Our model thickness (cm)
Surface Features
Feature
Orbit of Space Shuttle
Mt. Everest
Grand Canyon
Deepest well
Deepest ocean depth
Real Height (or depth)
km
300
8.8
1.7
8
11
Layer
Inner Core
Outer Core
Mantle
Density (g/cc)
12.7-13.0
9.9-12.1
3.3-5.5
Crust
2.7-3.0.
Our Scaled Size (cm)
Phase
Solid
Liquid
Solid and semisolid (“plastic”)
Solid
Composition
Iron
Iron, nickel
Magnesium, iron,
silicate
Silicate,
magnesium,
aluminum
Analysis questions
1. Which layer of Earth is thickest?
Thinnest?
2. If you saw Earth from outer space, how smooth would it appear?
3. How much of Earth would you see looking out a space shuttle window?
4. How do we know Earth has layers?
5. What happens to the density of Earth as you go toward the center?
6. Earth was a molten (liquid) ball of rock when it formed. Why did some
elements sink to the center?
7. Why might the outer core be a liquid?
Conclusion: