Blackboard optics - plane mirror.
An enclosed light source with a cylindrical lens is stuck to the blackboard by a suction cup. The light source produces a pencil of light which is parallel to the blackboard surface. A plane mirror surface is also held to the blackboard by suction cups, and reflects the beam so that the angle of incidence equals the angle of reflection.
|Blackboard optics||SW 008|
|or portable set||or 021-22F|