Transcript Convection and Density

Convection and Density
• convection currents
What are these?
• lava lamps
• How do they work?
Convection Lab
1. With no heat source, Draw the beaker
of water with the paper dots in it. Be
sure label the beaker, water, paper dots,
heat source and the path of movement
of the paper dots (if any).
Second Convection Demo
Second Convection Demo
7. a. Draw a picture of what you saw
happen in this demonstration. (Label
everything thing you can)
b. Explain why this happened. (complete
sentences)
c. What is this called.
Brainstorming Convection
8. Brainstorm with a partner and list as
many other examples of convection as
they can. Pairs share their ideas with the
class.
9. Draw one examples of convection?
Convection Lab
2. With the heat source ,draw the beaker
of water with the paper dots in it. Be
sure label the beaker, water, paper dots,
heat source and the path of movement
of the paper dots (if any).
Analysis of Data:
3. What are the 2 differences between your
observations for Diagram 1 and Diagram 2?
Analysis of Data
4. What did the path of paper dots in Diagram 2
represent?
Analysis of Data
5. This experiment is a model for processes that
occur within Earth’s mantle. What is the
heat source driving convection currents in
Earth’s mantle?
Causes of Plate Motion
• Heat from the Earth’s core causes materials in
the lower asthenosphere to become less dense
and rise up.
• When the materials come in contact with the
lithosphere they start to cool down and become
denser again.
• As the cooled magma falls and new heated
magma rises, it acts as a conveyer belt moving
the lithospheric plates.
Analysis of Data
6. Can convection occur within all fluids? Explain
using complete sentences.
Where is the heat source in the Earth
Located?
Why is the core so hot?
1. Hot from the formation
2. Heat from radioactive decay.
– Elements decaying into other elements and
releasing energy
Convection
• At which location
in the room will
the density of the
air be the
greatest?
Convection
• Convection: the transfer of heat through the
movement of a fluid
• Heat moves atoms apart causing the density
of the material to decrease
• Density influences the materials in the mantle
causing plate tectonic movement and
volcanic eruptions
Convection Currents
The middle mantle "flows" because of
convection currents.
Convection Currents
Convection currents are caused by the very hot material of
the mantle rising, then cooling and sinking.
Then the process is repeated when the material is heated
and rises, then cools and sinks again --repeating this cycle
over and over. mantle convection currents
How Do We Know All This, Anyway?
• We use seismic waves, from earthquakes to find
the depth of earth’s layers, like sonar in a
submarine.
How Do We Know All This, Anyway?
• We haven’t drilled deeper than the crust
• Shadow Zones: places on earth where no
seismic waves reach
• why does the earth have layers
•