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  • Skimming, skipping, Ducks and Drakes...

  • 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!

Skimming, skipping, Ducks and Drakes...

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B1 stone spinning water throw bounce angle

How to win at... stone skimming | Episode 5 | BBC Ideas

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    Summer posted on 2020/12/31
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