The Empty Bottle?
What do I need:
- A plastic bottle
- A sheet of paper
How do I do it?
STEP1 – Tear off a small piece of paper and scrunch it up into a ball so that it fits in the mouth of your bottle!
STEP2 – Lay your bottle on its side and put the scrunched up piece of paper into the mouth of the bottle, as shown!
STEP3 – Here’s where it gets fun! Challenge a friend to blow the piece of paper into the bottle (maybe place a sporting bet on it if you want to profit from science!). Try it – the piece of paper will come flying out!
What’s going on?
This is all to do with Bernoulli’s principle – he’s one of those scientists that everyone’s heard of but by no means everyone can remember what he said!
Bernoulli noticed that air has a lower pressure when it’s moving more quickly. As you blow into the mouth of the bottle the air is moving fastest – so is at the lowest pressure. Inside the bottle the air is moving more slowly – so a higher pressure. As the pressure is higher inside the bottle than in the mouth this pushes the paper out!
More Fun Please – Experiment like a real scientist!
- What happens if you don’t use a piece of paper? What else could you try instead?
- Is it possible? How can you blow the paper in?
- How does using different shapes and sizes of bottle change the experiment?