Lamed Vav Tzadikim: "I had a teacher who taught us about the nature of the element of silver in a class called Photo Science. He mentioned that one could never really see silver, because it was an element that was sensitive to light, the very moment the light hit the silver it would be changed. I can even recall the hand gesture my teacher made when he explained the concept. The idea he was explaining was that the surface of the silver we see, had already been exposed to light, and the very moment we scratch the surface of the silver (to see the unreacted silver underneath) it will have already changed."
'via Blog this'