Home >> Science & Nature >> Nature

How to Build a Barometer That Measures Millibars

Barometers detect air pressure by measuring the weight of tiny air particles. Air becomes compressed when it is placed under high pressure. Air pressure helps meteorologists predict changes in the weather. The possibility of inclement weather generally increases when barometric pressure is low. The most common unit of measurement used in barometers are millibars.

You can create a barometer that measures air pressure in millibars at home. The barometer in this tutorial will measure air pressure with a balloon seal that will dip when the pressure is high and inflate when the pressure is low, causing the measurement straw to move up or down.

Things You'll Need

Wide-mouthed glass, jar or small coffee can
Balloon or plastic wrap
Rubber band
Scissors
Drinking straw
Cardboard Strip
Glue or tape
Ruler and pen or pencil
Shoebox-size cardboard box

Instructions

- 1
  Cut off the narrow opening part of the balloon.
- 2
  Cover the top of the jar, wide-mouthed glass or coffee can with the balloon or plastic wrap so that it is airtight. To do this, stretch the balloon or plastic wrap over the rim of the container and secure it with the rubber band, making sure that that none of balloon or plastic wrap hangs slack.
- 3
  Squirt a dab of glue in the middle of the balloon and place one side of the straw onto the glue, so that the other side extends over the jar's edge. This completes construction of the barometer, minus the accompanying scale.
- 4
  Fold the piece of cardboard in half so that it can stand on its own. The cardboard will act as the barometer's scale.
- 5
  Create your millibars by marking lines 0.5 centimeters apart on the cardboard.
- 6
  Write "Low Pressure" at the bottom of the cardboard and "High Pressure" at the top.
- 7
  Place the barometer and cardboard scale in the box so that the end of the straw reaches without touching the scale. Tape the barometer and the scale so they cannot move apart.

Nature