© | Dror Bar-Natan's Image Gallery: Miscellaneous: | screen version print version |
On June 23, 2002, I took around 415 pictures of milk drops falling into a bowl of milk or a shallow puddle of milk. Here are the best 20 of the roughly 100 that actually had something in them. I don't have the equipment to take very rapid shots, and hence each frame came from a different drop, which were dropped from different heights. I tried to arrange them in "process order", but I'm not at all sure I understand the process well enough to have done it correctly!
First, here's a drop right before the splash. I estimate its diameter at about 4mm. |
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When the drop hits the surface, it creates an outgoing shock wave, which crests and becomes "a crown". |
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After the crown falls, all is left is a crater. The secondary milk drop seen is perhaps the tail of the original one, which splits off and falls more slowly because its relative surface area is bigger. | ||||||||||||||||||||
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Here the crater had refilled, and the impact of the secondary drop created a "crater within a crater": |
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When the crater refills, it closes up with such a force that a column of milk shoots up and then falls down: | ||||||||||||||||||||
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Now on to some pictures of splashes into a shallow layer of milk:
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This nice crown-splash has a secondary drop about to hit its middle: |
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In these two pictures the secondary drop falls back and creates a secondary crown-splash: |
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Finally, here's a collapsed crown, with a secondary crown in the middle, and a ternary drop about to splash: |
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Do it yourself! I took a milk carton, stuffed its opening with a paper towel and let it stand sloped down on a chair, so that I got a constant flow of milk drops down to the floor, at a rate of one per maybe 10 seconds. Down below was the bowl/puddle, and around 30 centimeters away I had my camera on a tripod, focused manually on the impact point. I used the camera's flash as a strobe light to hold the motion, and also used a very fast exposure time - 1/1000sec or so. The point of the fast exposure was not to hold the motion - that was achieved by the flash - it was just to make sure that from the perspective of ambient lighting the pictures would be hugely underexposed. So I could play with everything at normal room lighting and yet have a dark room and a strobe light in as much as the camera was concerned. With this setup I took my 415 pictures or so, watching each one on the screen of my digital camera and getting better at synchronizing with the drops as I went along. I'm sure you can do better!
Environmental Statement: The bowl I used is tiny (8cm diameter, 2cm deep) and in total I used less than half a cup of milk.