Objective: To construct several models to demonstrate the principle of convection, and to use your observations to explore the role convection plays in the development of atmospheric circulation and ocean currents.
Materials:
1. 1 Clear Plastic Box
2. 1 Beaker .50ml
3. 1 Pipette
4. 6 Styrofoam Cups
5. Food Coloring
6. Water (hot and cold)
7. Ice Cubes
Materials:
1. 1 Clear Plastic Box
2. 1 Beaker .50ml
3. 1 Pipette
4. 6 Styrofoam Cups
5. Food Coloring
6. Water (hot and cold)
7. Ice Cubes
Pre-Lab Questions:
1. Match the term below with it's definition.
A- Radiation: The transfer of heat by infrared waves
B - Conduction: The transfer of heat by touching.
C - Convection: The transfer of heat in a fluid that rises due to density differences.
2. If one beaker contains 100mL of cold water, another contains 100mL of hot water, which beaker contains more molecules? Explain.
- The beaker of cold water has more molecules, since it is more dense.
3. Which water, hot or old, would have higher mass? Which would have higher density?
- The cold water would have higher mass and density.
4. As you open a refrigerator door, what happens to the air inside?
- The cold air escapes from the bottom, sinking toward the floor.
5. As you lift the lid from a pot of soup, do the gases that escapes rise from the pot, or sink around its base? Why?
The top, since they rise from the pot.
6. If swim to the bottom of a pool and place a cork on the bottom, will the cork stay in place? Why or why not?
- It can, depending on it's depth and density.
7. Both air and water are fluids. What will happen to an area within a fluid that becomes warmer than the surrounding fluid?
- It will rise and we will have an area of low density or pressure.
8. Atmospheric pressure is the pressure exerted on the earth by the force of gravity pulling the air towards the earth's surface. Where air is rising from the surface, will the atmospheric pressure be increased or decreased?
- The atmospheric pressure will decrease.
Follow-Up Questions:
1. During the lab, what effect did cups of hot water have on the density of the water directly above them?
- It makes the water less dense by heating up.
2. What happened as a result of this change?
- Since there are two hot water cups under two of the red dots, only two red dots rised up at the same time.
3. A house has glass "sun space" attached to its south side, which is just a space all around the house, next to the outside wall, that holds air. Vents allow air to flow from the house into the sun space, and vice versa. Describe the direction air flows in the sun space is warmed by the sun.
- The warm air would go up and the cold air would sweep out.
4. You may have noticed convection cells in a pot of boiling macaroni. Describe the direction of water flow in the pot. The hottest part of the burner is beneath the center the of the pot.
- The water will flow upward and around the pot.
5. Which situation would result in a decrease in atmospheric pressure at the earth's surface?
- Air gets hot and begins to rise.
6. Go back to the three diagrams you constructed in your lab. Label the spots in each diagram that became areas of lower pressure.
7. Above which area would the air become hotter in the afternoon?
- A parking lot with lots of blacktop pavements.
8. Above which area would you find you find the lowest air pressure?
-The parking lot.
9. Based on this arrangement, would you except a breeze to blow toward the parking lot, or away from it? Why?
- The wind would blow towards the parking lot.
10. From your knowledge of onshore and offshore breezes, explain why the wind would blow in from the sea toward the land during the afternoon?
- Onshore and offshore breezes blow toward the land during the afternoon, because of the different temperatures of on land and the ocean.
11. A monsoon effect may happen in the summer as air over a continent becomes much warmer than air over the ocean. Fill in the blanks.
- A) As air over the continent becomes hotter, it will begin to sink.
- B) This causes lower pressure over the continent.
- C) The flow of air will be toward the center of the continent.
12. Think globally now. Which region in our atmosphere is heated most intensely by the sun?
The equatorial region
13. As air near the equator rises, does this become an area of higher or lower pressure?
- It becomes an area of lower pressure.
14. What moves in to replace the rising air?
- Cooler air moves into replace the rising air.
15. Number the following stages of atmospheric circulation (1-4) in the order which they are most likely to occur.
- 1. uneven heating
- 2. area of low pressure develops
- 3. convection (air rises)
- 4. wind (movement of air)
16. If hotter air rises, why is air that is closer to the Earth's surface warmer than the high air above it?
- Conduction and the layers of the surface.
17. Wind is considered to be a form of solar energy. Explain why.
- Solar energy is formed in order of uneven heating, area of low pressure develops, convection, and then lastly wind.
1. Match the term below with it's definition.
A- Radiation: The transfer of heat by infrared waves
B - Conduction: The transfer of heat by touching.
C - Convection: The transfer of heat in a fluid that rises due to density differences.
2. If one beaker contains 100mL of cold water, another contains 100mL of hot water, which beaker contains more molecules? Explain.
- The beaker of cold water has more molecules, since it is more dense.
3. Which water, hot or old, would have higher mass? Which would have higher density?
- The cold water would have higher mass and density.
4. As you open a refrigerator door, what happens to the air inside?
- The cold air escapes from the bottom, sinking toward the floor.
5. As you lift the lid from a pot of soup, do the gases that escapes rise from the pot, or sink around its base? Why?
The top, since they rise from the pot.
6. If swim to the bottom of a pool and place a cork on the bottom, will the cork stay in place? Why or why not?
- It can, depending on it's depth and density.
7. Both air and water are fluids. What will happen to an area within a fluid that becomes warmer than the surrounding fluid?
- It will rise and we will have an area of low density or pressure.
8. Atmospheric pressure is the pressure exerted on the earth by the force of gravity pulling the air towards the earth's surface. Where air is rising from the surface, will the atmospheric pressure be increased or decreased?
- The atmospheric pressure will decrease.
Follow-Up Questions:
1. During the lab, what effect did cups of hot water have on the density of the water directly above them?
- It makes the water less dense by heating up.
2. What happened as a result of this change?
- Since there are two hot water cups under two of the red dots, only two red dots rised up at the same time.
3. A house has glass "sun space" attached to its south side, which is just a space all around the house, next to the outside wall, that holds air. Vents allow air to flow from the house into the sun space, and vice versa. Describe the direction air flows in the sun space is warmed by the sun.
- The warm air would go up and the cold air would sweep out.
4. You may have noticed convection cells in a pot of boiling macaroni. Describe the direction of water flow in the pot. The hottest part of the burner is beneath the center the of the pot.
- The water will flow upward and around the pot.
5. Which situation would result in a decrease in atmospheric pressure at the earth's surface?
- Air gets hot and begins to rise.
6. Go back to the three diagrams you constructed in your lab. Label the spots in each diagram that became areas of lower pressure.
7. Above which area would the air become hotter in the afternoon?
- A parking lot with lots of blacktop pavements.
8. Above which area would you find you find the lowest air pressure?
-The parking lot.
9. Based on this arrangement, would you except a breeze to blow toward the parking lot, or away from it? Why?
- The wind would blow towards the parking lot.
10. From your knowledge of onshore and offshore breezes, explain why the wind would blow in from the sea toward the land during the afternoon?
- Onshore and offshore breezes blow toward the land during the afternoon, because of the different temperatures of on land and the ocean.
11. A monsoon effect may happen in the summer as air over a continent becomes much warmer than air over the ocean. Fill in the blanks.
- A) As air over the continent becomes hotter, it will begin to sink.
- B) This causes lower pressure over the continent.
- C) The flow of air will be toward the center of the continent.
12. Think globally now. Which region in our atmosphere is heated most intensely by the sun?
The equatorial region
13. As air near the equator rises, does this become an area of higher or lower pressure?
- It becomes an area of lower pressure.
14. What moves in to replace the rising air?
- Cooler air moves into replace the rising air.
15. Number the following stages of atmospheric circulation (1-4) in the order which they are most likely to occur.
- 1. uneven heating
- 2. area of low pressure develops
- 3. convection (air rises)
- 4. wind (movement of air)
16. If hotter air rises, why is air that is closer to the Earth's surface warmer than the high air above it?
- Conduction and the layers of the surface.
17. Wind is considered to be a form of solar energy. Explain why.
- Solar energy is formed in order of uneven heating, area of low pressure develops, convection, and then lastly wind.
SETUPS
Setup A:For this setup, we filled the plastic container with water and placed it on top of 8 styrofoam cups, each being stacked by two. Then, we placed 3 spots of red food coloring on the bottom, being careful while inserting the pipette and taking it out. After we placed the food coloring, we placed a water of hot water under the middle spot. This caused the middle spot to rise up and have low pressure. The area of high pressure was on the outside of the left and right areas.
Setup B:We repeated filling up the structure from Setup A, but this time, we put 2 cups of hot water under the left and right food dyes. The left and right areas then became areas of low pressure, whereas the areas of high pressure were near the middle spot.
Setup C:Rather than having three drops of food coloring, we only put two. Along with this, we also got a blue ice cube to put on the opposite side of the drops of food coloring. We set two cups of hot water underneath the red food coloring and they became areas of low pressure. However, there was an area of high pressure near the ice cube.