How can something stay completely dry underwater? Experiment and test some different ways to do it before reading our solution!
- Wad up a piece of paper and place it inside the cup; make sure it will not fall out if the cup is upside down (you can stick a piece of folded tape underneath to make sure)
- Fill a bucket with water, higher than the height of the cup
- Hold the cup upside down (with the paper inside) and lower it into the bucket of water; make sure it is pointing straight down vertically
- Now lift the cup (keep it straight vertically!) all the way out of the water
- What happened to the paper? Experiment with different ways of putting the cup in and out of the water to see what happens.
How does it work?
The air inside the cup is matter and therefore takes up space. As the upside down cup enters the water, the air inside it fills the space and prevents the water from entering.
