Splash!

Have you been enjoying Splash! on TV?

We certainly have - especially the bellyflops...

It's got us thinking - what kind of physics is involved in completing the perfect dive?

When Tom Daley takes off from the 3 metre springboard to complete a one and a half forward somersault in the pike position, how can science explain it?

To start off, take a look at the video below to see the man himself in action...

 

First the technical bit...

To understand the science behind spinning objects, like divers doing somersaults, we have to know a little bit about the "law of conservation of angular momentum".

Sounds complicated, but let's try to break it down a bit:

Angular momentum is a combination of the speed of a spinning object and the way that the mass of that object is arranged around the axis (centre) of the spin.

This means that if an object is spinning on its own (no friction or engine) then its angular momentum has to stay the same.  However, the speed of the spin can change - it just means that the way the mass is arranged will have to change too.

 

Let's think about a female ice skater in the Olympics:

She wants to do a pirouette on the ice and she starts the spin with her arms stretched out. Once she is spinning she pulls her arms into her sides (rearranging the mass of her body around the axis), which makes her turn faster and faster.  When she wants to stop spinning she spreads her arms out again to slow down.

 

Now take a look at this animation to find out the part that physics plays in Tom's spectacular somersaults...