Kelly Brechin

Balloon inside the Bottle

SCIENCE CONCEPT: Pressure. Air moves from areas of high pressure to areas of low pressure. Also, two objects cannot be in the same place at one time. The air blown into the balloon cannot take over the air already in the bottle.

MATERIALS:

2 two-liter bottles

Nail

Two balloons

DIRECTIONS:

1. Take one two-liter bottle and poke a hole in the bottom using the nail.

2. Place a balloon on the inside of each two-liter bottle. Make sure the balloon is wrapped around the mouth of the bottles.

3. Have students try to blow up each balloon. The balloon over the bottle without a hole should not blow up.

4. Plug up the hole in the two-liter bottle and observe what happens to the balloon.

INTRODUCTION:

How many of you like to have competitions? Well, today I have a game for two of you to play. Are there two people in the audience who would like to help me? The object of the game is quite simple. Each of you needs to try and blow up a balloon. The trick is the balloon has to be blown up inside one of these bottles. Are there any questions? Well then let's begin. Ready, Set, Go!!!

EXPLANATION:

The two-liter bottle with a hole in it is allowing air to be released out of it. The bottle without a hole has all of the air trapped inside of it. The balloon inside the bottle without a hole cannot inflate because there is too much air surrounding it inside the bottle. The pressure of the gas molecules around the balloon will not allow the balloon to inflate. The balloon inside the bottle with the hole in it can be blown up because there is no pressure surrounding it inside the bottle. All of the air is being released through the hole in the bottle. When the hole is plugged, the pressure on the inside of the bottle is equal to the pressure on the outside of the bottle. Since the pressures are equal, the balloon stays inflated even without being closed off.

REFERENCE: Unknown