Download Geology Lab: "Edible Tectonics"

Name____________________________
Modeling Convection Currents
BACKGROUND INFORMATION:
The movement of heat from a warmer object or area to a cooler object or area is called heat
transfer. Convection is heat transfer that takes place as the result of currents. Convection takes
place within a fluid. Large amounts of heat are transferred through Earth via convection
currents. Some of these currents are in Earth’s liquid outer core. Other convection currents are
present in the mantle.
Convection currents in the mantle form and transfer heat as rock slowly rises toward the top
of the mantle. The rock is still hard, but it flows very slowly like a fluid. As the rock rises, it
cools and sinks back down into the mantle. As with all convection currents, convection in
Earth’s mantle is the result of three things: heating and cooling of rock material, changes in the
rock’s density, and the force of gravity.
Because it is not possible to directly observe the mantle, scientists sometimes make models
to study how this part of Earth moves. Based on their findings, they make inferences and draw
conclusions.
Hypothesis:
Do hot liquids rise or sink?
MATERIALS:
 Large /small glass
beaker
 Small glass beaker
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Small pieces of paper
Hot and cold tap water
Aluminum foil & gloves
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Food coloring
Rubber band
Pencil with a sharp point
PROCEDURE:
1) Fill the large beaker with a water and ice mixture to reach the 800 ml level.
2) Fill the small beaker about ¾ full with tap water and stir in 5 drops of food coloring. Heat
the water until it reaches 80°C.
3) Remove the beaker using the glove and add warm water until the beaker is filled to the brim.
Cover the top of the small beaker with aluminum foil and secure with a rubber band.
4) Carefully lower the small beaker into the large beaker of cold water.
5) Place the pieces of paper on the surface of the cold water.
6) Without disturbing the water, use the tip of the pencil to make two small holes about 2 mm in
diameter in the aluminum foil covering the jar.
7) Observe the contents of the beaker and the paper pieces on the surface of the water.
8) AFTER ANSWERING THE QUESTIONS BELOW, throw away the pieces of paper, pour
the water down the FRONT sink, and place your supplies near the sink.
9) Make sure to clean your desk area!
OBSERVATIONS/ RESULTS:
1) Describe what happened to the colored water and to the pieces of paper after the holes were
punched in the material covering the beaker. Draw a picture with labels to aid your
explanation.
2) What part of your model represented tectonic plates? What part represented the
asthenosphere in the mantle?
3) Did the warm water rise or did it sink? What happened to the warm water when it touched
the ice layer?
4) Which is most dense, cold water or warm water? Is ice more or less dense than water?
Defend your answer.
5) What makes the tectonic plates move?
6) What color water will eventually move to the bottom of the small beaker?
7) Draw a picture of continental crust and oceanic crust converging. Label each piece of crust
and use arrows to show which way the crust is moving. Put in arrows to illustrate a
convection current in the mantle below the crust.
8) Which is the most dense, continental crust or oceanic crust?
CONCLUSION: Below is a clear box filled with water. Two sealed jars are in the box.
Use arrows to trace the path that colored water would travel if it was placed in location 1 in the
diagram below. Use arrows to trace the path that colored water would travel if it was placed in
location 2 in the diagram below.
2
warm water
Cold water
1