Try this with a grown-up
Feel the pressure
In How Deep Is the Ocean? the deep sea squashes Captain Cup. This bottle shows why: the deeper the water, the harder it pushes.
A grown-up pokes the holes.
You will need
- An empty plastic bottle with the lid off
- Sticky tape
- A skewer or a sharp pencil (for a grown-up)
- Water
- A sink, a bath or the garden
What to do
- Ask a grown-up to poke three small holes in a line up the side of the bottle: one near the bottom, one in the middle and one near the top.
- Cover all three holes with one strip of sticky tape.
- Fill the bottle to the top with water and stand it in the sink or outside.
- Pull the tape off and watch the three jets.
- The jet from the bottom hole squirts out fastest and hardest.
Why does it work?
The water at the bottom has all the water above it pressing down on it, so it pushes out the hardest. The sea works the same way: the deeper you go, the harder the water presses. At the bottom of the deepest sea, nearly 11 kilometres down, it presses more than a thousand times harder than the air does at the surface. That is what squashed Captain Cup.
It goes with Episode 2, How Deep Is the Ocean?
Watch the episode