Brilliant video demonstrating multiple physics concepts. Identify the instrument in the center and for bonus cookie points, tell us which principle is responsible for the effect seen when UV light is cast on the instrument.

Oh, there is a Zinc plate on the instrument. That is very vital for the effect you saw.

Cracked by: Rogi, tanwi, rickde, Vishwas B Sharma, shrik, jowens, Manish Achuth, Raghuvansh and raklodramA