Water droplets
Droplets of coloured water skitter around on a hot plate. A simple and beautiful film.
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Duration: 02:24
Views: 636
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Water DropletsFilming technical subjects like this is often tricky, and this certainly was. We moved the camera quite a long way back, then zoomed in to fill the screen with the hotplate. This reduces the effective 'depth of field' - which means the background behind the drops goes all blurry, helping them stand out.
Trouble is, unless you're focussed in exactly the right spot, the drops go blurry too. If you look closely you can see the camera 'hunting' back and forth, as it tries to work out what to focus on. We should have turned autofocus off, and done it by hand - ah well, next time.
Be very careful repeating this experiment, of course: not only does the hotplate have to be extremely hot, but the fizzing droplets spit boiling water around. Eye protection and gloves, people!
I love this film - the physics is quite subtle, the crackly sound is wonderful, and the pictures are fabulous - it looks beautiful!
To recap Glen's explanation: when the hotplate is hot enough, water boils on contact. But the boiling is so rapid, the resulting water vapour (gas) doesn't have time to move out of the way of the rest of the droplet. So the droplet 'floats' on a layer of gas. And it turns out that water vapour is quite a good insulator, in the circumstances, so the rest of the droplet only boils rather slowly, refreshing the gas layer as it does.
Since the droplets are supported by the gas layer, they also skitter around madly, floating on their low friction support and pushed about as they wobble and boil.
Be very careful repeating this experiment: not only does the hotplate have to be extremely hot, but the fizzing droplets spit boiling water around. Eye protection and gloves, people!
This movie was made by a group of teachers and professional science communicators during one of our training workshops; we subsequently finished it off (adding the bluescreen effects, and editing some of the lines so the physics is correct, or at least not wrong).
So, while it's a lovely little film, it wasn't really fair to enter it into the competition.
Jonathan, 31 Dec 2008
This film is far better then most of the other nominated films. Why this movie wasn't nominated for any awards?
Posh Norbert, 22 Dec 2008
not bad but that wasnt very resourceful! Nice experimentation but further explanation can be given!`
abi.c, 17 Jun 2008
awesome. my favourite
dza, 24 Sep 2007
Try and get the hotplate level and it will be much more beautifull :D
Zander, 02 Sep 2007