Astronomy
Lab: Greenhouse effect
Astronomy Lab Instructions
The Greenhouse effect
Goal: To measure the Greenhouse effect
Materials:
- Lamp with three-way bulb
- Stopwatch
- Thermometer
- Tall Glass Jar, beaker, or (if necessary) a zipper-style gallon bag. Jar or beaker should have an air-tight stopper or sealable hole into which you can insert the thermometer without it touching the sides.
- Ruler
Procedure:
- Control experiment:
- With the lightbulb off, record the thermometer reading (room temperature).
- Set the thermometer about 5 inches from the light bulb.
- Turn on the lamp for five minutes at the lowest energy setting.
- Record the new thermometer temperature.
- Turn off the light and let the thermometer return to room temperature.
- With the lightbulb at the same setting, record 5-minute temperature increases for the thermometer when it is 10, 15, and 20 inches from the bulb.
- Repeat your measurements for at least one other power setting for the bulb.
- Greenhouse experiment:
- Repeat the procedure above, but this time, put the thermometer in the jar, beaker, or gallon bag and seal it. Make sure to position the thermometer so it does not touch the sides of the container. Record the temperature after five minutes at each location used previously, with the same bulb.
- EXTRA CREDIT: Blow into the bag through a straw; suck the air back out, hold it in your lungs, and blow it back in. Do this 2-3 times with the same air, so that you increase the CO2 and water vapor content. Seal the thermometer in the bag and repeat your distance and wattage measurements. Remember to let the thermometer come back to room temperature each time.
Data Analysis:
Make a table and list your data:
| Recording # | Distance from Bulb | Bulb Wattage | Starting Temperature | Ending Temperature | Difference |
|---|---|---|---|---|---|
| Control 1 | 5 in | 26 W | 38 °C | 42 °C | 4 °C |
| GreenHouse 1 | 5 in | 26 W | 38 ° C | 44 °C | 6 °C |
Analyze your data. What are the trends as you
- increase distance from the lamp.
- increase or decrease wattage.
- use a "greenhouse".
Report:
Submit your report to the Moodle website. From your data, comment on the difference you would expect in surface temperatures for airless planets, planets with thin atmospheres, or planets with thick, CO2 atmospheres.
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