The magic of physics (or vice versa)
The last post I wrote was about the extended essays I am supervising, one of them is about the physics behind a magic trick so here is Elliot performing the trick. The reason you can't see the pen is because light from that region of the bottle will be totally internally reflected on its way out to the observer. To make the idea of a blind spot clearer Elliot took rays travelling in the opposite direction to show that there is a region that parallel rays cannot reach, here I have used Algodoo to simulate the situation. This implies that an object placed here would not be seen by a distant observer.
