Gizmos Convection Cells - Answer Key Student Exploration: Convection Cells Vocabulary: convection, convection cell, density, global conveyor belt, mantle, mid-ocean ridge, subduction zone, vector, viscosity Prior Knowledge Questions (Do these BEFORE using the Gizmo.) You place a pot of soup on the....
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
You place a pot of soup on the stove. As the soup warms you notice some areas where soup is
rising up and other areas where soup is sinking down.
1. Why do you think some of the soup is rising up?
It has the highest temperature.
2. Why do you think some of the soup is sinking down?
The effects of boiling.
Gizmo Warm-up
When fluids (gases or liquids) are heated, they tend to move.
This motion is called convection. In the Convection Cells
Gizmo, you will observe and experiment with convection both
in a laboratory setting and in several real-world examples.
To begin, note the laboratory setup on the MODEL tab. A
beaker of liquid is placed above a gas burner. Click Play ( ).
The burner is now heating the fluid.
1. What do you notice?
It is moving in a circle.
2. Drag the eyedropper into the beaker just above the burner and let go to release a drop of
orange liquid into the beaker. What do you notice about the path of the drop?
It floats up and down in a circular motion.
Activity A: Get the Gizmo ready:
Convection Click Reset ( ), and set Burner A to High.
Question: What causes convection cells to form?
This study source was downloaded by 100000826990473 from CourseHero.com on 01-26-2022 04:40:21 GMT -06:00
2019
, 1. Hypothesize: Click Play, add a drop, and watch the motion of the liquid. Why do you think
convection tends to occur in heated fluids?
It moves at a faster pace. Convention occurs in heated liquids because of the difference in
temperature.
2. Observe: Click Clear drop. Under Show, select Temperature. The temperature scale runs
from red (hot) to dark blue (colder).
A. Where is the hottest liquid located? Bottom
B. Where is the coldest liquid located? Top right corner
C. Add a drop. Does the hottest liquid tend to rise or sink? Rise
D. Does the coldest liquid tend to rise or sink? Sink
3. Observe: Click Clear drop, and then add a new drop to the liquid. Turn on Show micro
view of drop. This view shows 21 molecules in the drop. Pay attention to how fast the
molecules move and how much space they occupy as the drop moves around the beaker.
(Note: If the drop gets stuck, add a new drop to the beaker.)
A. In which part of the beaker do the liquid molecules move fastest? Closest to burner
B. In which part are the liquid molecules most spread out? Hottest part
4. Explore: Click Clear drop and drag the probe ( ) into the beaker. Density is defined as the
mass per unit volume. It is a measure of how tightly the particles of a substance are packed.
Move the probe to different parts of the beaker, observing the temperature and density.
A. What relationship do you observe between the temperature and density? The liquid
that are less dense will float.
B. Why do you think this is so?
The temperature affects the size of molecules. It expands with heat and shrinks with
cold.
(Activity A continued on next page)
Activity A (continued from previous page)
5. Explain: In a liquid, objects denser than the liquid (such as rocks) tend to sink, while objects
less dense than the liquid (such as inflatable rafts) tend to rise. How does this relate to the
observed motions of the liquid in the beaker?
The warmer liquid is less dense and rises to the top. The colder liquid is denser and sinks.
Convection occurs because heated fluids become less dense, causing them to rise. Cooled
fluids become denser, causing them to sink.
This study source was downloaded by 100000826990473 from CourseHero.com on 01-26-2022 04:40:21 GMT -06:00
2019
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