Weight Some Air

When something is very light, people often say “It’s as light as air”. But air is not light at all. Do this simple experiment to show that air is really quite heavy.

Materials:
1. Balloon pump
2. Two balloons
3. Rubber band
4. Two Drawing Pins
5. Long thin piece of wood
6. Ruler
7. Pencil
8. Sticky tape
9. thread

Procedures:
1. Use the ruler to find the centre of the wood. Then mark it.
2. Push a drawing pin into each side at the centre mark.
3. Tie the thread to the middle of the rubber band.
4. Fix the loops of the rubber band around the drawing pins. Lift the wood by the thread. It should balance.
5. Tape one of the balloon to one end of the wood.
6. Tape the second balloon to the other end of the wood. Check that it still balances. Then remove one balloon and blow it up.
7. Tie the neck of the blown-up balloon and attach it to the wood in the same place as before. The balloon make the wood lose its balance.

Drinking with a straw.
When you drink through a straw, the weight of the air helps you. The air above the drinks pushes on the surface of the liquid. As you suck, it forces the liquid up through the straw to your mouth.