Air pressure is measured with an instrument called a barometer. Try making your own simple barometer.

You will need
a) a plastic container
b) a straw
c) an elastic band
d) a sellotape
e) a balloon
f ) a piece of cardboard

Steps

1. Cut a small piece from a balloon, stretch it over the top of a plastic container and secure it with an elastic band.

2. Tape a straw to the middle of the balloon.

3. Mark a scale on a piece of card and fix it beside your barometer.

4. Check your barometer at the same time each day and mark where the straw comes to on the scale. Changes in air pressure will make the ballon and straw move slightly up and down.