This is a video of the “Time Fountain” I built with my friend Aaron D’mello for our grade 12 Physics Fair project.
The Time Fountain uses an array of ultraviolet LEDs to make a drop of aqueous sodium fluorescein fluoresce (glow). These LEDs are strobed rapidly in sync with the drop frequency, this creates the effect of a drop caught in time. If you offset this frequency slightly you can produce the effect of slowing down or even reversing time.
The video below shows the “stopped time” effect, the “slow motion” effect, and the “reverse time” effect. Due to the strobing lights, the video did not come out that well, but the effect was amazing in real life and resulted in the first-ever 100% grade at the Physics Fair.
We built the electronics without a microcontroller using a simple 555 timer circuit and three potentiometers for coarse, medium, and fine strobe control.