Using Suction to Blow Up a Balloon

Equipment Needed

1 balloon
1 rubberband
2 glass tubes
Jar with tightly fitting cork
Tool for drilling holes in cork

The Experiment

Use the rubberband to fasten an uninflated balloon to the end of one of the glass tubes.

Remove the cork from the jar.

Drill two holes through the cork, each large enough for a glass tube to fit through.

Place one glass tube in each hole

Replace the cork on the bottle, making sure the seal is airtight.

The tubes should now be inside the bottle, with the uninflated balloon also inside the bottle.

Place the end of the tube without the balloon in your mouth and suck in air.

The balloon will expand.

How it Works

When you remove air from the jar via the tube without the balloon, air enters the tube with the balloon so that the pressure in the jar is maintained. This causes the balloon to expand.