Have you ever wanted to see a gas in action?
With this simple experiment, using things you can find at home, you can observe the phenomenon of gases taking up space, and what happens when you play around with forcing air in and out of spaces.
Ask an adult to help you with this experiment
Air is a collection of different gases, and gases take up space in the same way as liquids and solids, it’s just usually a little bit harder to see. The first time you tried to blow up the balloon, it would have worked as normal, and the balloon would have got bigger. The air you blew into the balloon forced the air already inside the bottle out of the hole at the bottom. The next time however, when you tried to blow the air into the balloon, there was nowhere for the air in the bottle to flow, so you couldn’t force any air into the balloon. This is because your finger trapped the air inside the bottle from flowing out, which meant there was no room for the air you were trying to force into the balloon.
You can extend this activity by investigating what happens when you blow the balloon up inside the bottle, and then hold your finger over the hole. The air will stay in the balloon, and not rush out of the top of the bottle. Why is this?