Sonoluminescence is probably one of the coolest phenomena you’ll come across and involves conditions that over a fraction of a millisecond swing from -269C degrees to upwards of 10000C.
source/image: The Thought Emporium
By trapping a bubble with ultrasound you can force it to expand and then suddenly contract and in the moment of peak compression out comes a flash of light.
In this video we explore how you can easily recreate this effect with very minimal hardware, and some of the other times this effects shows up, like when a mantis shrimp punches things.
The sonoluminescence effect was first discovered at the University of Cologne in 1934 as a result of work on sonar. Its causes remain a mystery, and there hasn’t been much research on the subject for reasons that become apparent in the video: It’s hard to recreate, and historically, there haven’t been many practical uses.