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Learning Lesson: Its a Gas, Man

OBJECTIVE Discover if carbon dioxide has an effect on temperature.
OVERVIEW The demonstration will show that excess carbon dioxide leads to higher temperatures.
TOTAL TIME 1 hour
SUPPLIES Two (2) clear 2-liter bottles.
Two thermometers
Molding clay
Two seltzer tablets
Table top lamp used as a source of heat
PRINTED/AV MATERIAL None
TEACHER PREPARATION None
SAFETY FOCUS Summer safety rules
 Background  
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Carbon dioxide has increased greatly in the atmosphere over the past 100 years. Although it comprises only 0.03% of the atmosphere, it has been linked to global warming.

 Procedure  
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  1. Partially fill both bottles with water.
  2. Add the seltzer tablets to one of the bottles.
  3. Suspend the thermometers inside the bottles in such a way that you can measure the temperature of the air and seal the tops with molding clay.
  4. Place the lamp at equal distance between each bottle.
  5. After an hour, measure the temperature of the water in each bottle.
 Discussion  
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The seltzer tablets supplied one bottle with a source of carbon dioxide. The "fiz" will have heated faster and to a higher temperature than in the other bottle. The increase in heating ability is due to carbon dioxide's high capacity to hold heat.

It has been thought that an increase in carbon dioxide will lead to global warming. While carbon dioxide in the atmosphere has been increasing over the past 100 years, there is no evidence that it is causing an increase in global temperatures.

In 1997, NASA reported global temperature measurements of the Earth's lower atmosphere obtained from satellites revealed no definitive warming trend over the past two decades. In fact, the trend appeared to be a decrease in actual temperature.

The largest differences in the satellite temperature data were not from any man-made activity, but from natural phenomena such as large volcanic eruptions from Mt. Pinatubo, and from El Niño.

The behavior of the atmosphere is extremely complex. Therefore, discovering the validity of global warming is complex as well. How much effect will the increase in carbon dioxide will have is unclear or even if we recognize the effects of any increase.

 Live Weatherwise  
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Summer Safety Rules
Thinking About Your Environment
  • Protect windows. Hang shades, draperies, awnings, or louvers on windows that receive morning or afternoon sun. Outdoor awnings or louvers can reduce the heat entering the house by as much as 80%.
  • Conserve electricity. During periods of extreme heat, people tend to use a lot more power for air conditioning, which can lead to a power shortage or outage. Vacuum air conditioner filters weekly during periods of high use.
  • Keep lights turned down or turned off.
  • Avoid using the oven.
Fast Facts
To see the full effect of the greenhouse effect, one only needs to look to the planet Venus.

The atmosphere of Venus consists of 96% carbon dioxide, 3.5% nitrogen, with the remaining amount, less than 1%, of other gasses.

The carbon dioxide atmosphere has allowed the temperature of the surface to exceed
900°F (482°C).

This is hot enough to melt lead. Space craft that have successfully landed on venus, despite being well protected, have lasted only about an hour in the excessive heat and crushing pressure.
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National Weather Service
Southern Region Headquarters
819 Taylor Street
Fort Worth, Texas 76102
www.srh.weather.gov
Updated: January 6, 2005
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