Beautiful and challenging, the Pendulight demonstrates the use of photochromic material to record movement. It is an exhibit that arouses coriousity and encourages conversation among visitors.

The advantage of writing with light is that the 'light pen' does not touch the writing surface. Since there is no friction, the Pendulight can continue swinging for a long time. Furthermore, there is no need to erase the drawing or to replace sand, pens, or paper. Pendulight can either stand alone or be incorporated into exhibits on Mechanics, Newton's laws of motion, Harmonic oscillations, Clocks and Time measurement.