Mundesley Junior School - Projects - Sink or Swim

Have you ever tried taking a ball of plasticine and put it into a jam jar full of water. What happens?

Have you then tried taking that same piece of plasticine, flatten it out and place it again in the jar of water? What happens?

Interestingly 'what happens' isn't the same both times.

Why?

That's what this series of experiments we are going to do is all about.

Have you watched that chap walking on custard on Braniac? Walking on a liquid?
There's a good chance you can't watch the video at school but go home and click this link.

Walking on custard.

That's walking on custard until he stops. Then he sinks?

Sink or Swim Experiments

Why boats float and elephants sink?

It Floats

The Loony Experiment

Bouyancy Basics

Different Viscosities

Archimedes Simulation

Bouyancy in the wild.

This is a Great Northern Diver and it can sink under the water in a matters of seconds. How does it do this?

Amazingly Americans and Canadians call them Loons

The loon

chick can swim right away, but spends some time on the back of a parent to rest, conserve heat, and avoid predators
has many bones that are solid, rather than hollow like those of other birds, which aid its diving ability
can stay under water for almost a minute and dive to depths of 80 m
may have to run as far as several hundred metres on the surface of the water on a calm day before gaining enough speed to take of.

We gratefully acknowledge permission to use the two pictures of Great Northern Divers by the photographer Sindri Skulason.

Listen to the incredible sound it makes and see the full size pictures at Mull Birds by Alan Spellman

Click here for an amazing beast that can smell underwater.

Read about the Star Nosed Mole

Another amazing creature that's worth a look is the Whirligig Beetle

Only creature to swim on the surface film of water.

They have eyes that can see above and below the water at the same time.