Active Time
30-45 minutes
Total Project Time
30-45 minutes
Key Concepts
Air pressure, weather, density
A glass jar, balloon, rubber band, and wooden skewer act as a modemade barometer

The end of a wooden skewer is attached to a balloon stretched over a glass jar. When air inside the jar expands or contracts the rubber membrane of the balloon will either push out or pull in, moving the free end of wooden skewer up or down. A simple chart of high and low pressure is placed behind the end of the wooden skewer that hangs off the jar so when the balloon moves the skewer will point to high or low pressure readings on the paper.


Have you ever seen a weather forecast on TV? If so, you might have noticed the letters "H" and "L" moving around on the weather map. They are often referred to as zones of "high pressure" (H) and "low pressure" (L). The pressure they are talking about is the atmospheric pressure. Changes in air pressure can forecast short-term changes in the weather. But how do you know if the air pressure changes, or if it is high or low? Scientists have developed an instrument called a barometer that can measure atmospheric pressure. In this activity, you will find out how a barometer works by building one yourself!


Svenja Lohner, PhD, Science Buddies
This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Heat-resistant glass jar
  • Rubber band that fits around the mouth of the glass jar
  • Balloon
  • Wooden skewer
  • Scissors
  • Tape
  • Paper
  • Pencil
  • Bowls (3)
  • Tap water (hot, cold)
  • Ice cubes
  • Paper towels



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Active Time
30-45 minutes
Total Project Time
30-45 minutes
Key Concepts
Air pressure, weather, density
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