Whatever you call it, if you want to send a stone

bouncing across the surface of the water

there's a surprising amount of science and technique involved.

It's almost the same science that allowed engineer and inventor

Barnes Wallis to create the bouncing bomb

used in World War Two, to attack German dams -

the so-called Dambusters raid.

OK, so first you need to find the right stone.

Wonky shaped, thick-set, pockmarked stones are not recommended.

Don't worry about it being perfectly smooth,

but the ideal stone is flat and round -

rather like a digestive biscuit, though maybe not quite as big.

It just depends on the size of your hand.

The key to a good throw is spin.

The gyroscopic effect

stabilizes the stone, as long as it is spinning fast enough,

preventing it from tipping over and falling into the water -

just like a spinning top has to be spinning fast enough to stay upright.

Amazingly, it's this same gyroscopic effect

that keeps the Earth spinning on its fixed axis in space.

There are lots of ways to grip and throw the stone,

but here's a good one to try.

Grip the stone with your thumb and fingers,

with your index finger around the edge.

As you throw, bend down as low as you can and aim towards the water,

keeping the stone horizontal.

A good angle for the stone to bounce when it hits the water

is about 20 degrees.

At this angle, even a beginner can get away with a sloppy throw.

But if you're good, and you can throw the stone both level and fast,

then go for as shallow an angle as you can.

It's your index finger that will do all the work

generating speed and spin in the direction of the two arrows.

The whip of your wrist creates extra spin.

Lift your thumb off the stone at the last minute.

Get it right, and you'll see more than two bounces.

Who knows, on flat water

you might get the stone to bounce 10, 15 or even 20 times.

But don't expect to get into the Guinness Book of Records.

In 2013, Kurt "Mountain Man" Steiner from the US

managed to get his stone to bounce a record-breaking 88 times!