Make a Barometer
What you'll need:
A rubber band
A piece of card
A marker (felt pen)
1. Cut the top off the balloon (the part which you blow into).
2. Stretch the balloon over the top of the jar and hold it in place with a rubber band.
3. Place the straw across the top of the jar so that one third of the straw is hanging over the edge. Stick the straw to the balloon with tape.
4. Draw three lines on the piece of card that are about half a centimeter apart from each other. Label these lines as high, moderate and low.
5. Tape the card against the back of the jar so that the straw points to moderate.
6. Put your barometer on a flat surface somewhere inside.