Make a barometer and predict the weather. As the air is sealed inside the jar, any changes to the air pressure outside the jar will direct the movement of the balloon rubber. As the outside air pressure increases, the rubber will be forced down into the jar. The straw pivoting on the glass will rise upward. The opposite is true when the pressure decreases.
Weather forecasters use barometers to help predict the weather.
Cut the bottom half off the balloon.
Pull the top half of the balloon tight over the jar.
Use the rubber band to keep the balloon tight over the jar.
Fix the straw to the center of the balloon skin using a piece of tape.
Place the paper so that it is lined up against the straw. Draw a line at this position.
Above the line write the word “high” and below the line write “low”.
Note the pressures each day to see if you can notice a pattern between your air pressure readings and the weather outside.