How to make a barometer

This mini science investigation shows you how to make a DIY barometer to measure air pressure. Air pressure can be used to predict the weather and is one of many factors used by meteorologists.

What does low or high pressure mean for the weather?

Low pressure usually means wet, cloudy, rainy weather while high pressure is an indicator of dry and cool weather.

DIY Barometer

Barometers are used to measure atmospheric pressure.

What is atmospheric pressure?

The Earth has a layer of air surrounding it. This air has weight and presses down the Earth. At higher altitudes the air is thinner so air pressure is lower.

diagram showing the different in air pressure at different altitudes

To make a barometer you will need

Jar or coffee can

Elastic band

Pin or cocktail stick





How to make a barometer

Blow up the balloon a little bit, the more air in the balloon, the greater the pressure outwards which is what makes the balloon blow up.

Let the air out of the balloon and cut the tie end off.

Stretch the balloon tightly over the jar or can and either tape or use the elastic band to fix it tightly.

Tape or glue the end of the straw to the centre of the balloon and tape the pin or cocktail stick to the end.

Tape some card behind the barometer and mark where the pin is.

Leave for a few days and note any changes. Record what the weather is like each day and note how it affects the barometer.

DIY  barometer made with a jar and balloon.

How does the DIY barometer work?

Warm air expands and rises, lowering the pressure of the air on the ground below. Cold air is heavier, it sinks and presses down on the ground forming a high pressure area.

The higher the air pressure the more air presses down on the balloon, pushing it into the jar and making the straw rise.

More weather activities for kids

Did you know you can make a weather station using pine cones?

Find out how movement of hot and cold air causes a sea breeze.

Find out what shape a raindrop really is.

Or, try one of my other weather science experiments for kids.

Science concepts

air pressure

atmospheric pressure

DIY Barometer

Last Updated on September 16, 2022 by Emma Vanstone