What I meant to say was that everyone who was watching the experiment, saw the waves standing still. It was just that not everyone was looking at the experiment in the first place, but the few who did look, saw the same thing.
So if I used a battery powered lamp (at a different frequency)...
Thank you!
And when you say, if my experiment seems to slow then reverse like in that video, do you mean when I change the frequency? Because that's what occurred for me! Though I'm still wondering why it was at precisely 66.7 Hz that it seemed to be still.
If it were the wagon-wheel effect...
oh I see, my apologies! so this could be a trick of the eye.
Is there any formula's regarding the stroboscopic effect?
And if this was a trick of the eye, I think I read somewhere that us (humans) see real motion at 24 frames/second...could that relate to this matter?
No I don't think that the motor vibrates the mirror.
Is there an explanation for the cause of the waves to appear still? This was witnessed by a few students so it can't be the trick of the eye. But is there any theory behind the cause? Because I need to find out the reason why this occurred...
Thank you for your reply, Dadface and also Simon Bridge.
The waves were lit with a hanging light that was hung (approximately) 10 cm above the waves.
Here's a photo of the experiment:
The lights in the room weren't on as it was daytime.
For an experiment involving a ripple tank and a wave monitor, the frequency was changed from 10Hz to 100Hz and it was found that at precisely 66.7Hz, the wave produced appeared (to the viewer) to be standing still. At any value below 66.7 Hz the wave moved inwards, and at any value above 66.7Hz...