Candy Bar PlateTectonics
Name________________________
This candy bar activity uses a scale model to introduce some of the
basic concepts in plate tectonics. Plate tectonics explains a wide variety of
observations and phenomena. It explains, for example, the distribution of earthquakes and
volcanoes in the world. It explains how many of the surface features like mountain ranges, ocean
trenches, and fault lines were formed. It also explains how our atmosphere obtained some of its gases.
To understand plate tectonics, remember that the lithosphere is broken up into a number of
plates. Some of these plates are large, while others are small. Although the plates touch, they are not
connected to each other and they move independently.
The crust of the earth and upper part of the mantle form the lithosphere. The lithosphere rides
on top of the asthenosphere, or molten magma in the mantle. Many geologists believe that the flow of
rock in the asthenosphere causes plate motion in the lithosphere. Below the mantle are the liquid,
metal outer core and solid, metal inner core.
In areas where the lithosphere plates move apart, rift valleys can form along the mid-ocean
ridge. This also allows out gassing which releases gases into the atmosphere. Where plates collide,
they form ocean trenches, mountain ranges, and volcanoes.
Procedure:
1. Unwrap the Milky Way Bar and put it on the paper towel. Describe what you see and smell. (be
sure all trash ends up in the trashcan before you leave!)
2. Use your fingernail to make a few cracks in the middle, top of the candy bar. Describe what
you see and smell.
3. Slowly stretch the candy bar by pulling it apart just a few centimeters. Describe what you see
and smell.
4. Slowly push the stretched candy bar back together again. Describe what you see and smell.
5. Repeat steps 3 and 4 several times. Observe how the candy bar has changed.
6. When you are finished answering all questions you may eat your model 
Plate Tectonics Candy Bar Model
Activity What You See What You Smell How This Models Plate Tectonics
(Hint: relate your model to Earth’s Plates and Interior)
Step 1
Step 2
Step 3
Step 4
Analysis Questions:
1. Using the candy bar as a model for the earth. What does each layer of the candy bar represent?
a. Chocolate outside:
b. Caramel:
c. Nougat:
2. Include one fact about each layer of the earth.
a.
b.
c.
3. Describe what you observed when the candy bar was pulled apart. Where does this action
occur on our Earth?
4. Describe what you observed when the candy bar was pushed together. Where does this occur
on Earth?
5. What is the lithosphere?
6. What is the asthenosphere?
7. Explain the frequent occurrence of earthquakes and volcanoes along the boundaries of the
plates.