How to build a barometer?

You need :

- a straw

- a glass

- a balloon

- 2 nails

- 2 elastic bands 

- 2 small planks

1. Cut the balloon; fix it to the top of the glass.

2. Fix the balloon with elastic bands.

3. Fix one end of the straw to the balloon.

4. Nail the two planks together.

 5. Cover the planks with the paper. Draw a line on the paper at the height of the straw.

6. Draw a sun, draw a cloud and staple the sheet of paper to the plank.

7. The barometer works with the pressure. When the straw is up it’s sunny whereas when the straw is down it’s cloudy.