Show your students how meteorologists measure atmospheric pressure with this homemade barometer. This simple and quick activity will give your students the opportunity to simulate the ways that atmospheric data is collected in the real world.
The Southeast Regional Climate Center provides great and easy instructions that you can use in your own weather and climate lessons.
A barometer is a scientific instrument used to measure atmospheric pressure. It is often used to predict weather and determine altitude. It is an essential tool in the field of meteorology and can tell us a great deal about atmospheric conditions. The barometer is intended to be kept at a certain altitude and used to detect small changes in pressure that are caused by the weather. In order to measure air pressure, barometers measure how much the air is pressing down on it. While modern barometers are electronic, there are two traditional types of barometers: Torricellian and aneroid barometers.
Invented in 1643, the Torricellian barometer used mercury and glass tubes to measure air pressure. This was accomplished by creating a vacuum inside the glass tube (the first time this was accomplished in a laboratory setting) and measuring pressure by the rising and falling of the liquid mercury in the tube. However, mercury is a rather dangerous substance so this method has fallen out of use.
Aneroid barometers have air-tight metal boxes that respond to changes in pressure. Rising or falling air pressure causes the box to expand or contract and move the attached pointer on the dial. In order to get a more accurate up to date reading, you’ll need to tap on the glass of the barometer. The barometer in this activity reflects the mechanics of an aneroid barometer.
Want more information? Visit National Geographic to learn more.
What You’ll Need
To create your own aneroid barometer, you’ll need the following items:
- glass jar or tin can
- large round balloon
- rubber band
- thin wooden dowel
- 5 x 7 index card
How to Make the Barometer
You can build the aneroid barometer in 6 easy steps. Refer to The Southeast Regional Climate Center for a printable handout with these steps.
- Use the scissors to cut the top of the balloon off.
- Wrap the top of the balloon tightly around the opening of the jar or can and seal it with the rubber band. Try to get the balloon as tight as possible and make sure that the rubber band is tight enough so that no air will get in.
- Tape the stirring stick to the center of the stretched out balloon so that one end of the stick points away from the jar or can.
- Place the jar or can next to a wall. Tape the index card to the wall so that the end of the stick is pointing to it.
- Make a mark on the index card next to where the stick is pointing. You may wish to
label the mark with the date and time.
- Look at the card each day and see if the stick points above or below where it did the
day before. If it points above the previous day’s mark, the pres
MS-ESS2-5 Earth’s Systems
Disciplinary Core Ideas
ESS2.C: The Roles of Water in Earth’s Surface Processes
- The complex patterns of the changes and the movement of water in the atmosphere, determined by winds, land forms, and ocean temperatures and currents, are major determinants of local weather patterns.
ESS2.D: Weather and Climate
- Because these patterns are so complex, weather can only be predicted probabilistically.