- 2 balloons (equal size)
- 2 plastic sticks / straws. One of them is 30 cm, one of them is 15 cm. If you use straw, cut the bent one, so everything is straight.
- 2 coke cans or any cans
- Stick tape
- pencil
- Use your ruler to mark the centre of the 30cm plastic stick / straw with the pencil (try to mark it in the accurate place)
- Fix one balloon at each end of the 30cm stick / straw with sticky tape.
- Tape either end of the 15cm plastic stick / straw to a can. Place the centre mark of the 30cm stick / straw on top.
We want to prove that air have weight. Maybe in this experiment, the 30cm stick/straw will be balance, if you blow another balloon then that balloon is bigger than the another one, the 30cm will be not balance anymore.