Cloud in a Bottle Lab
Record all answers on your OWN sheet of paper! Do NOT write on the lab sheet! Write the question and your hypothesis on your paper: I) Ask a question – How and why do clouds form? II) Form a Hypothesis – III) Test the Hypothesis Materials needed: Jobs to Do one clear 2 liter bottle (rinsed out) Materials Manager / Thinker warm water Jot ‘em Down Journalist match Temperature Taker / Thinker temperature strip Bottle Boss / Thinker tape H2O Hauler / Thinker |
A) Unscrew the cap and with a small piece a tape, carefully attach the temperature strip to the INSIDE of the neck of the 2 liter bottle. Screw the cap back on the bottle. (see above picture)
B) Read and record the temperature of the air inside the bottle as indicated by the temperature strip. Squeeze the bottle so it compresses the trapped air and increases the pressure inside the bottle. Hold it this way to keep the air compressed while carefully watching the temperature strip. Record the temperature of the compressed air. After a half minute or so, release the pressure by letting up on the bottle. Continue to carefully observe the temperature for at least a minute. Record the temperature of the uncompressed air.
Answer these questions on YOUR paper:
1) Initial temperature: _________________
2) Squeezed bottle air temperature: ________________
3) Unsqueezed bottle air temperature: ________________
4) What happened to the temperature as a result of the bottle being squeezed, which compresses the air inside and increases the pressure?
5) When you released the bottle so the air inside was no longer being squeezed and decreased the pressure, what happened to the air temperature in the bottle?
6) So, what does that tell you about how the changes in air pressure affect temperature?
7) Air pressure decreases as you go up in altitude. This is because air pressure is determined by the weight of the air above it. This means as air goes up it experiences lower pressure and expands. Based on your findings above, what must happen to the temperature of air rising through the atmosphere?
8) What happens to the temperature of air when it moves downward in the atmosphere?
C) Open the bottle and pour just enough warm (not steaming hot!) water in it to cover the bottom of the bottle. Twist and turn the bottle to wet the inner surface. Cap tightly and let stand for a couple of minutes so enough water evaporates to saturate the air.
D) Open the bottle. Have the teacher light a match, blow it out, and insert the match into the bottle opening. Quickly cap the bottle tightly. The smoke was added to the air because water vapor needs a surface (like dust, pollution, or smoke) on which to condense.
E) Now apply and release pressure on the bottle as before, keeping track of temperature changes. Look very carefully in the bottle for any evidence of a cloud. It will look more like fog than the big puffy white clouds. If you can’t see a cloud, repeat squeezing and releasing pressure on the bottle until you do.
9) Initial temperature: _________________
10) Squeezed bottle air temperature: ________________
11) Unsqueezed bottle air temperature: ________________
12) Did the cloud form when you applied pressure or when you released pressure?
13) Did it form when temperatures rose or when they fell?
IV) Analyze the Results
14) Most clouds in the atmosphere form in the same basic way as the cloud in the bottle. In your own words, using what you’ve learned in this lab, how do clouds form?
15) How did you make the cloud disappear in the bottle? Why did it disappear?
16) Most clouds in the atmosphere appear and disappear the way your bottle cloud did. State in your own words how temperature and pressure have an effect on cloud formation and dissipation (going away).
V) Draw a Conclusion
17) Generally, do you think high-pressure areas (H) in the atmosphere tend to be clear or cloudy? How about low-pressure areas (L)? Why? (Hint, think about what you’ve learned in this lab!)
VI) Communicate Results
18) Answer this question in a paragraph: How and why do clouds form?
B) Read and record the temperature of the air inside the bottle as indicated by the temperature strip. Squeeze the bottle so it compresses the trapped air and increases the pressure inside the bottle. Hold it this way to keep the air compressed while carefully watching the temperature strip. Record the temperature of the compressed air. After a half minute or so, release the pressure by letting up on the bottle. Continue to carefully observe the temperature for at least a minute. Record the temperature of the uncompressed air.
Answer these questions on YOUR paper:
1) Initial temperature: _________________
2) Squeezed bottle air temperature: ________________
3) Unsqueezed bottle air temperature: ________________
4) What happened to the temperature as a result of the bottle being squeezed, which compresses the air inside and increases the pressure?
5) When you released the bottle so the air inside was no longer being squeezed and decreased the pressure, what happened to the air temperature in the bottle?
6) So, what does that tell you about how the changes in air pressure affect temperature?
7) Air pressure decreases as you go up in altitude. This is because air pressure is determined by the weight of the air above it. This means as air goes up it experiences lower pressure and expands. Based on your findings above, what must happen to the temperature of air rising through the atmosphere?
8) What happens to the temperature of air when it moves downward in the atmosphere?
C) Open the bottle and pour just enough warm (not steaming hot!) water in it to cover the bottom of the bottle. Twist and turn the bottle to wet the inner surface. Cap tightly and let stand for a couple of minutes so enough water evaporates to saturate the air.
D) Open the bottle. Have the teacher light a match, blow it out, and insert the match into the bottle opening. Quickly cap the bottle tightly. The smoke was added to the air because water vapor needs a surface (like dust, pollution, or smoke) on which to condense.
E) Now apply and release pressure on the bottle as before, keeping track of temperature changes. Look very carefully in the bottle for any evidence of a cloud. It will look more like fog than the big puffy white clouds. If you can’t see a cloud, repeat squeezing and releasing pressure on the bottle until you do.
9) Initial temperature: _________________
10) Squeezed bottle air temperature: ________________
11) Unsqueezed bottle air temperature: ________________
12) Did the cloud form when you applied pressure or when you released pressure?
13) Did it form when temperatures rose or when they fell?
IV) Analyze the Results
14) Most clouds in the atmosphere form in the same basic way as the cloud in the bottle. In your own words, using what you’ve learned in this lab, how do clouds form?
15) How did you make the cloud disappear in the bottle? Why did it disappear?
16) Most clouds in the atmosphere appear and disappear the way your bottle cloud did. State in your own words how temperature and pressure have an effect on cloud formation and dissipation (going away).
V) Draw a Conclusion
17) Generally, do you think high-pressure areas (H) in the atmosphere tend to be clear or cloudy? How about low-pressure areas (L)? Why? (Hint, think about what you’ve learned in this lab!)
VI) Communicate Results
18) Answer this question in a paragraph: How and why do clouds form?