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Try making a barometer yourself.

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Making a barometer doesn't require that much scientific expertise, even though the concept may seem a bit complicated. A barometer measures the atmospheric pressure, meaning the force exerted on a specified area by the earth's atmosphere.

Firstly, there are 3 major types of barometers: the water barometer, the aneroid barometer, and one that uses mercury, similar to many thermometers.

Aneroid barometers work without using any liquid. Instead, they have a sealed metallic chamber equipped with flexible upper and lower surfaces that bend with changing pressure.

We can construct mercury barometers from a glass tube and an open dish filled with mercury combined with a vacuum pump. The height of the mercury column correlates to the barometric pressure.

The water barometer uses water for the same purpose as mercury in the example above, but, because of its lower density, making a barometer of using water could be quite daunting as typical atmospheric pressures support over thirty feet of water in a column.

The column of water is better for indicating variations in atmospheric pressure rather than the absolute pressure. Additionally, alcohol can be substituted for water with similar results.

When making a barometer…

Try this: Use alcohol.

• Find a glass tube around 35" in length
• Seal one end of it with chewing gum or putty
• Then get a small glass, a few ounces of colored alcohol, scotch tape, a yardstick, a 2x10" sheet of cardboard and a ring stand equipped with a clamp to complete this project
• Fill the tube with alcohol and then pour the remaining liquid into the small glass
• The tube has to be inverted, placed into the glass and held in place by the clamp
• Mark the height in inches on the cardboard to point out the pressure and then use the yardstick to calibrate the device
• Do this by sliding the cardboard up or down until your pressure reading in inches is correct.

Or this: An alternative way to build barometer gadgets. Start with a drinking straw, a balloon, several rubber bands, some scotch tape, a piece of cardboard and a toothpick.

Inflate the balloon to stretch it, release the air and then, after cutting its neck, spread the remaining part over the mouth of the jar and seal it with a rubber band. Take your toothpick and tape it to one end of the straw.

Attach the straw's other end to the center of the disc defined by the balloon. The cardboard serves as a measuring scale: fold it in a triangular shape and fasten the ruler to the center of the triangle. The toothpick moves to show the increases and decreases of the atmospheric pressure in this aneroid design.

Making a barometer using household liquids and items is a good experiment that demonstrates how to keep track of the pressure in a fashion similar to how weather observers measure it.

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