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typo fixed, better explanation
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Quillo
Quillo
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You already have a very nice answers and commentsanswer, just let me point out that you probably have already seen this effect at work: sometimes very fast-moving wheels seem to move in reverse.

The flow in the fountain is not reversed, the droplets are falling. However, if you create a "periodic" system of droplets (in fact there are several droplets that are almost equally spaced), you can use the illusion given by the " wagon wheel effect ". After all, the periodic system of droplets is just aan "unrolled cycle"wheel" and the effect is due to a "samplingsampling error of a periodic signal"signal (every time the stroboscope light switches on your eyes take a "snapshot" of the droplet's actual configuration).

Here you can play with a periodic signal and see what happens when you modify the sampling rate.

NoteNote#1: also the neon lamps have a discharge frequency of ~50 Hz, so they can create a stroboscope effect, thus, any. Any machinery rotating at multiples of this frequency may appear to not be turning. This and this can creategive rise to safety problems in factories.

Note #2: if you really want to levitate water droplets, you may use something like an acoustic levitator.

You already have nice answers and comments, just let me point out that you probably have already seen this effect at work: sometimes very fast-moving wheels seem to move in reverse.

The flow in the fountain is not reversed, the droplets are falling. However, if you create a "periodic" system of droplets (in fact there are several droplets that are almost equally spaced), you can use the illusion given by the " wagon wheel effect ". After all, the periodic system of droplets is just a "unrolled cycle" and the effect is due to a "sampling error of a periodic signal" (every time the stroboscope light switches on your eyes take a "snapshot" of the droplet's actual configuration).

Here you can play with a periodic signal and see what happens when you modify the sampling rate.

Note: also the neon lamps have a discharge frequency of ~50 Hz, so they can create a stroboscope effect, thus, any machinery rotating at multiples of this frequency may appear to not be turning. This can create safety problems in factories.

You already have a very nice answer, just let me point out that you probably have already seen this effect at work: sometimes very fast-moving wheels seem to move in reverse.

The flow in the fountain is not reversed, the droplets are falling. However, if you create a "periodic" system of droplets (in fact there are several droplets that are almost equally spaced), you can use the illusion given by the " wagon wheel effect ". After all, the periodic system of droplets is just an "unrolled wheel" and the effect is due to a sampling error of a periodic signal (every time the stroboscope light switches on your eyes take a "snapshot" of the droplet's actual configuration).

Here you can play with a periodic signal and see what happens when you modify the sampling rate.

Note#1: also the neon lamps have a discharge frequency of ~50 Hz, so they can create a stroboscope effect. Any machinery rotating at multiples of this frequency may appear to not be turning and this can give rise to safety problems in factories.

Note #2: if you really want to levitate water droplets, you may use something like an acoustic levitator.

Source Link
Quillo
Quillo
  • 5.2k
  • 1
  • 18
  • 45

You already have nice answers and comments, just let me point out that you probably have already seen this effect at work: sometimes very fast-moving wheels seem to move in reverse.

The flow in the fountain is not reversed, the droplets are falling. However, if you create a "periodic" system of droplets (in fact there are several droplets that are almost equally spaced), you can use the illusion given by the " wagon wheel effect ". After all, the periodic system of droplets is just a "unrolled cycle" and the effect is due to a "sampling error of a periodic signal" (every time the stroboscope light switches on your eyes take a "snapshot" of the droplet's actual configuration).

Here you can play with a periodic signal and see what happens when you modify the sampling rate.

Note: also the neon lamps have a discharge frequency of ~50 Hz, so they can create a stroboscope effect, thus, any machinery rotating at multiples of this frequency may appear to not be turning. This can create safety problems in factories.