Download convection demonstration2

NAME: ________________________________
PERIOD: __________
CONVECTION DEMONSTRATION
(WHY PLATES MOVE)
What forces would lead to the movement of the plates over the surface of the earth? At this time it is
believed this movement results from mantle convection. Mantle convection is the slow creeping motion
of Earth's plastic mantle caused by currents carrying heat from the interior of the earth to the surface.
KEY WORDS:
Lithosphere- The rigid, shallowest portion of Earth. Where the continental and oceanic plates are located, as well
as the rigid mantle that underlies them.
Asthenosphere- Also referred to as the “plastic mantle.” Because it is plastic, rather than rigid, it is able to flow,
but it IS NOT FLUID
Mantle- Portion of Earth below the crust and above the core
Magma- Molten material inside the earth (as opposed to lava)
Radioactive decay- The breakdown of unstable atoms
Convection- Circulation of a material due to heat
Use the convection demonstration and the key words listed above to answer the following questions:
1. Outline the entire path of the oil beginning and ending with its being heated by the hot plate
(follow the pieces of wrapping paper). Color your lines RED where WARM, LESS DENSE material
is rising and BLUE where COOLER, MORE DENSE material is sinking.
2. How does the oil in the demonstration behave like the asthenosphere?
3. How do you think the oil demonstration is different than convection within the asthenosphere?
4. What is the connection between heat and density (this is the whole reason why convection
happens)?
5. Look at the picture to the right. Where does a
very small amount of the molten material in
the real-world mantle convection end up rising
to the surface (what kind of plate boundary)?
6. What does this molten material form when
cooled?
7. In our demonstration, the heat generated was created by a hot plate. In the mantle, convection
is fed by radioactive decay, or the breakdown of unstable atoms, which releases heat. If the
earth as a whole is cooling down, what do you think that tells us about radioactive decay today
compared to earlier stages of earth’s development?
8. What is the connection between where divergent boundaries occur and convection?