Why does ice make sparks when being cracked out of the ice tray?

Question

Has anyone noticed that in complete darkness (eyes adjusted) when you crack ice out of the ice cube tray (plastic tray), the ice has faints bits of light coming from the bottom of the cubes? Give it a try! ph 7.0, hardness ppm 250

Answer 1

Physicists are not in general agreement as to what causes the flash. There are two [1] main contending explanations: piezoluminescence and triboluminescence [2]. The former suggests that when removing the ice cubes by twisting the tray, we deform the cubes (put it under pressure) and the vibrations induce the release of light. The latter suggests that the breaking of electrical bonds (either within the ice crystal between individual water molecules, or between the ice and the tray) releases enough energy to allow an electron to cascade through the orbitals and release energy in the form of light.