EFFECT OF TEMPERATURE ON AIR

KEY CONCEPTS

  1. Atmospheric pressure is somewhat dependent on temperature. When air is heated, it expands and rises; conversely, when it cools, it contracts and sinks.
  2. High-pressure areas occur where air cools, increases in weight, and sinks toward the earth's surface.
  3. Low-pressure areas occur where air warms, decreases in weight, and rises; This often creates unsettled weather conditions.
 

MATERIALS

  • soda bottle, balloon and candle
  • bowl of ice
  • ruler and string
  • student journals
 
 

PROCEDURE

  
 
 

Activity

  1. Blow a small amount of air into the balloon and place its opening over the mouth of the bottle.
  2. Use the string and ruler to measure the height and distance around the middle of the balloon (i.e., its circumference). Record the data in student journals.
  3. Carefully warm the bottle over the flame of the candle and observe the balloon. Measure and record the height and circumference of the balloon.
  4. Let the bottle cool and then submerge it in the bowl of ice. Again, measure the balloon's dimensions and record the results.
  5. Discuss the results and have students draw conclusions about the effects of temperature on air pressure.
  6. Relate results to a current weather map in which high-pressure areas (and settled weather) and low-pressure areas (and unsettled weather) are indicated.
 
 

Assessment Ideas

  • Create a QuickTime movie of the experiment
  
 
 

CROSS-CURRICULAR IDEAS

  • Mathematics/ technology: Use probes to measure the actual change in pressure and temperature. Graph the results.
  • Biology (research topics): Discuss the effects of pressure on human beings. What happens to fighter pilots who fly where the air is thin? What about astronauts in the Space Shuttle?
  • Physics (research topics): In space, away from sunlight, it is very cold. Where there is light, the temperature can significantly incerase. How do you compensate for this when designing a spacecraft?
  • English/history: Read a book that has something very specific about the effects of air pressure and humans in the main plot. Make a report and highlight the problems and how they were solved.
 
 

VOCABULARY

  • high-pressure areas: large regions where the atmosphere cools, increases in weight, and sinks back toward Earth's surface.
  • low-pressure areas: large regions where the atmosphere warms, decreases in weight, and rises, often creating unsettled weather conditions.
  
 

SOURCE

  • Adapted from "Winds of Change" educational CD-ROM, Copyright Caltech and NASA/Jet Propulsion Laboratory