Image formation

SCI 1.3, PHYS 1.4, PHYS 2.3 , JNR SCI

Place object (such as the toy piglet) at the centre of the bottom dish and assemble the cover mirror. The object will appear to float above the hole.  Remarkably, a laser beam pointed at the image from above will appear to reflect from the image, a sort of mirage reflection. In fact the beam is entering the hole and reflecting off of the real piglet!. If the laser is pointed at the image from the side it will not enter the apparatus and will thus pass through the image. Even more remarkably, the laser beam can be blocked by placing a finger either in front of the image (between the laser and the image) or behind the piglet. Thus a finger placed in the beam behind the piglet makes the mirage reflection disappear from the front of the piglet. There is a paper in Physics Teacher, October 2006 that gives instructions for making a cylindrical device that produces a somewhat similar effect. The device is very inexpensive to construct. We made one quickly and it works well. (M. A. Caussat, H. Rabal, M. Muramatsu, The Levitating Buddha: Constructing a Realistic Cylindrical Pseudo Image, The Physics Teacher, Vol 44, Page 443).

 

We suggest you use the film as the laser beam can emerge in unpredicted directions. At least exercise the usual laser safety practices. Note the beam spreads at sufficient distances as the mirror is not flat.

www.optigone.com takes you to the web site for the manufacturer. The ray diagram above is taken from their web site.