Time Distortion Strobe Fountain Thing

September 14th, 2006 by Ben Goldacre in not bad science | 18 Comments »

This has got to be the most elegant geek toy I have seen since we got back from Dorkbot: it’s just a UV strobe light, shining on a steady stream of fluorescent water drips, but by tweaking the timing, you can make the drips stop, and go backwards or forwards. The most amazing thing, though, comes in the second half, where they show how you can interact with the drops, whilst also making time flow slowly, or the wrong way. Mindblowingly beautiful. I am totally making one.

Full story at cre.ations.net, via the ever brilliant Make.

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18 Responses

  1. coracle said,

    September 14, 2006 at 9:42 pm

    That’s fantastic!

  2. JohnD said,

    September 14, 2006 at 9:51 pm

    Nice gadget, Ben!

    It made me think of another ‘light & water’ experiment I made for my kids years ago. I Googled for it and lo! It’s set out for primary teachers to do with theirs – and you could do for yours, even if it’s your inner child.
    See: www.sciencetransitionscotland.org.uk/newsletters/dec05.doc

    Just to whet your appetite for science wonders, it’s a light guide, total internal reflection at an air/light transmitter boundary, just like an endoscope fiber light guide, except the guide is water, not resin.


  3. pv said,

    September 15, 2006 at 12:19 am

    Is it the same kind of illusion as when spoked wheels rotating at a certain speed appear to be running in the opposite direction to reality?

  4. raygirvan said,

    September 15, 2006 at 12:43 am

    Yes. Temporal aliasing (essentially when you sample some periodic phenomenon at a frequency too close to that of the thing you’re looking at).

  5. Jam said,

    September 15, 2006 at 10:41 am

    You see this effect in the stream of a flow cytometer.

  6. raygirvan said,

    September 15, 2006 at 10:52 am

    The Wikipedia article on Wagon-wheel effect has some very interesting stuff I’d never encountered before about aliasing occurring under continuous illumination: details disputed, but apparently due to some interaction with the ‘frame rate’ or motion detection system in the human visual system.

  7. MikeTheGoat said,

    September 15, 2006 at 11:12 am


    I was just about to say that it reminded me of setting up a MoFlo. It’s much prettier though.

  8. Frank said,

    September 15, 2006 at 11:42 am

    I Stumbled upon this a few weeks ago – it’s fantastic!

  9. ceec said,

    September 15, 2006 at 2:35 pm

    Hey! this is the experiment they showed us as schoolkids that made me study physics A level (and nearly a degree – there but for the grace of god etc.). It’s beautiful.

  10. The Reverend AG said,

    September 15, 2006 at 4:24 pm

    That’s pretty frickin’ cool..

  11. Symball said,

    September 15, 2006 at 4:40 pm

    For anyone thinking of making it- watch out for the dye- it sticks to most things and won’t ever come out.

    I love this and would make it if my electronic engineering skills went further than wiring a plug

  12. Pete said,

    September 17, 2006 at 8:50 am

    JohnD: That’s a neat idea, I am going to have to make that for my children.

  13. BorisTheChemist said,

    September 17, 2006 at 12:35 pm

    You can actually do temporal alias with a a video camera and a droplet stream as well. Also your eyes have a “frame rate” too so you see such phenomena if the droplet stream is fast enough (I have observed this myself during some experiments using droplet streams).

  14. Robert Carnegie said,

    September 17, 2006 at 8:27 pm

    Do eyes have a “frame rate”? News to me. There is persistence of vision, or we couldn’t watch films and television (well, TV has its own persistence on the screen) – and electric light, particularly fluorescent and street lighting, has a visible pulse. Try waving your hand around with stretched-out fingers…

  15. BorisTheChemist said,

    September 19, 2006 at 2:51 pm

    The ” ” I hoped were enough to suggest that I was equating these optical illusions such as the Wagon Wheel Effect (see ray girvan’s link above) to simpler optical systems found in recording equipment rather than being absolute, it was an attempt to relate these phenomena to standard stroboscopy. Of course the eyes don’t have a true frame rate, but phenomena such as subjective stroboscopy are observed for whatever reasons to do with your brain. Perhaps the droplet stream stroboscopy I observed was actually to do with the fluorescent lighting though…

  16. Kells said,

    September 19, 2006 at 5:34 pm

    Ok I can understand the ‘temporal aliasing’ but I can’t get my head around the finger interacting with it. Quite amazing. As for making one?? Don’t you have a book to write?

  17. stever said,

    September 22, 2006 at 6:20 pm

    I think the frame rate of the eye is why spokes on wheels sometimes appear to go backwards, But its safe to say i dont know what Im talking about

  18. mikewhit said,

    January 3, 2008 at 1:28 pm

    Sadly, “This video is no longer available”