Hot Air Balloon Inflating

Use hot and cold air to inflate a balloon.

Continue reading "Hot Air Balloon Inflating"

Materials - balloons, plastic pop bottles, hot and cold water

The results of this experiment are more interesting if it can be done twice, first with a small bottle, and second with a large bottle. A third bottle (small) can be used as the control. The final step should be done in a sink or outside as water may overflow.

Directions

1. Stretch out the balloons as if you were about to blow them up.
2. Stretch the neck of a balloon over the top of two bottles the same size.
3. Pull the balloon down so that the neck of the balloon goes over all the threads of the bottle.
4. Place one bottle with the balloon into the freezer for 5 minutes, or 30 minutes for a dramatic effect.
5. Put the second bottle on the counter as a control.
6. If you have a large bottle and and extra balloon, put the balloon over the bottle and place it in the freezer too.
7. Run hot water to partially fill a sink, pitcher or pot.
   
8. Take the small bottle from the freezer and put it in the container of hot water until the water is ¾ up the side of the bottle. Hold it in place. Watch what happens.
9. Take the large bottle from the freezer and put it in the container of hot water until the water is ¾ up the side of the bottle. Hold it in place. Watch what happens.
10. Take the bottles out and empty the hot water.  Use room temperature water to fill the sink, pitcher or pot.
11. Put the control bottle in the container until the water is ¾ up the side of the bottle and hold it place. Watch what happens.

What should happen?

When the balloon was placed in the freezer for a short time, it would collapse. After 30 minutes, the cooling air sucks the balloon into the bottle.

When the bottle was placed in the hot water, the balloon should expanded slightly. When two different-sized bottles are used, the smaller one would have only expanded the balloon slightly; the larger bottle would have expanded it more.

The balloon on the control bottle should have remained unchanged.

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