“Let’s Make a Barometer,” Friend, Apr. 1983, 13
To make a barometer that will record coming weather changes, you will need: empty bottle, piece of balloon, rubber band, glue and toothpick. Place piece of balloon over mouth of jar and secure tightly with rubber band (see illustration). You have trapped air inside bottle with the air pressure of that moment. A decrease in pressure outside the jar expands the balloon (stormy weather); an increase depresses it (fair weather). By gluing toothpick to one side of balloon (see illustration). it will be easier for you to see any changes in air pressure, which will alert you to coming weather changes. Keep baromemter away from direct sunlight ot other heat source that might cause trapped air to expand.