Air expansion and air contraction
Do you like understanding how the world around you works? This surprising experiment will show you how air react to temperature changes. This experiment is divided into two.
How does it work?
These experiments just show how air reacts to temperature changes.
In experiment 1, warm air contained into the bottle is slowly getting colder. When air is cooling down, it contracts, and takes up less space. The balloon is stopping up the mouth opening, and therefore, exterior air cannot get inside of the bottle instead of contracted air. So the balloon is drawn up instead.
In experiment 2, cold air contained into the bottle is warming up when you put it in hot water. When air warms up, it expands, and therefore takes more space. The balloon is stopping up the mouth opening, so it receives the air and inflates.
Necessary materials
- Two balloons
- A plastic bottle
- A bassin/sink
- A jar
How to make this experiment?
Experiment 1
- Ask an adult to fill up the bottle with hot water, to stir it, and then, to empty it in the bassin.
- Place the balloon over the mouth opening of the bottle.
- Wait a moment, and the balloon will inflate in the inside!
- You can open a bit of the balloon to facilitate the experiment.
Experiment 2
- Put the bottle into the refrigerator, and take it back about 20 minutes later.
- Place the balloon over the mouth opening of the bottle.
- Ask an adult to maintain the bottom of the bottle into a bassin of hot water. You can reuse the hot water of experiment 1.
- Very quickly, you notice that the balloon is inflating out of the bottle!
