The Dipping Duck

I do like my scientific toys and none come much better than the one I call ‘Dippy’.

Dippy is shaped a bit like a bird and once you give him a drink of water he continues to dip his beak into it until he can no longer reach the water. It is as if by magic!

Here is Dippy.

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Dippy is an old bird – definitely over thirty. Sadly, his feet split many years ago and they are fastened up with splints – actually sticky pads.

To see Dippy working, click here.

Sorry folks, you’ll have to have a bit of science because, of course, Dippy is not magic. He’s a clever mix of well-balanced technology, a volatile liquid and a way of creating different temperatures.

Dippy’s head is covered by a thin layer of absorbent material. It gets wet each time he pokes his bill into the water. That water evaporates. In the film I have created a draught so that it all works quickly. When water evaporates it takes heat from the surroundings so the vapour in Dippy’s head is colder than the vapour in his tail end. That creates a pressure difference and the red liquid is forced up through Dippy’s pipe shaped neck. Eventually there’s more weight above his hip joint than below it and the head falls forward into the water. Whilst near horizontal the pressures can equalise and the liquid all falls back into the body sending Dippy to the upright position again. If you keep water in front of him he’ll drink indefinitely.

But for those who don’t like or who aren’t interested in the science, just enjoy the quirky shape keeping going for ever. For after all, it does seem like magic.

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