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Weather Experiment: Make Your Own Barometer

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Did you know you can make your own barometer from odds and ends you can find around the house? All you need is a can,

such as a coffee can, a straw, a balloon, a rubber band, some tape, and a straight pin. But first, what does a barometer measure anyway?

A barometric pressure instrument is useful to weather forecasters because it measures the atmospheric pressure. More specifically, a barometer is used to identify changes in the air pressure in a given area.

Air pressure is usually high during nice, sunny weather. This is because the heavy air tends to inhibit the formation of clouds. When the pressure starts to drop, there's a chance a storm is moving in.

Now for the production

To make your own barometer, cut the end off the balloon and stretch the rubber over the opening of the can. It will look a little like you are making a drum.

Use the rubber band to attach the balloon to the can. It needs to be an air-tight fit,

so arrange the rubber band until you are certain you have accomplished this. Using this sealed container makes this device into an aneroid barometer.

Now use some tape to attach the straw to the balloon piece. The straw should stick out to the side, with the other end taped to the center of the balloon. The straw will function as an indicator of the air pressure.

Tape the straight pin to the loose end of the straw in order to have a more precise indicator. Set the whole contraption in front of a piece of white paper attached to the wall and make a mark at the level where the pin is currently.

Over the course of a few days, check the barometer. Chances are, the straw will be pointing up or down.

When the straw points up, it is because the air pressure is heavier on the balloon. When the straw points down, it indicates less air pressure.

The air inside the can in such a case will be under more pressure than that outside, so it pushes up against the balloon.

These easy instructions will help you make your own barometer. This project would be fun for any age of school students. Wanna try something different? Find three other barometer designs described on these pages: How to make a barometer

Making a Barometer

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