Air pressure is an important variable for weather forecasting and tells you whether the weather will be sunny or rainy. So if you're bored this Christmas, why not make your own?

To get started you will need:

A glass such as a jam jar, a straw, a balloon, a rubber band, toothpicks (or cocktail sticks), tape, scissors, pen, ruler and paper, and glue.

Here we go!

To get the most accurate pointer, stick a toothpick to the straw with tape.

Now cut off the mouthpiece of the balloon, stretch it over the glass and fix a rubber band to secure it in place.

Next, snap a toothpick and glue it to the edge of the glass, follow this by gluing the straw in place in the centre of the balloon and resting on the pick.

That’s your instrument complete! Now for the scale.

Grab a cardboard box and stick paper on it and mark a scale with a ruler. You can draw a sun on top and a cloud on the bottom (more about that later).

It is important that the cardboard stands stable and that the distance between the cardboard and the barometer remains the same from now on.

We’re done, place your creation away from sunlight so that the pressure is not impacted by heat.

Be patient, when air pressure rises the pointer will move up towards the sun, a sign of good weather. When it falls the balloon will bulge and the pointer will drop to the cloud indicating bad weather is on the way.