PURPOSE: To demonstrate dramatically how a corner reflector works.

DESCRIPTION: The laser is mounted on a stand with the beam coming out a hole in the white baffle, and aimed across the room or to the rear of the lecture hall. Hold the corner reflector in the beam and the reflected beam will return to be easily seen on the white card. Rotate the corner reflector and change its angle, showing that the beam still returns to the card. The specular reflection of the laser beam off the front surface of the glass will also be seen moving around the room.

SUGGESTIONS: This is the same type of corner reflector that was placed as an array of corner reflectors on the moon for retroreflector experiments. Some web sites describing these experiments are:

1. Jet Propulsion Laboratory: experimental data (1999).
2. Apollo 11 Laser Ranging Retroreflector Experiment
3. Measuring the Moon's Distance:Apollo Laser Ranging Experiments Yield Results (from LPI Bulletin, No. 72, August, 1994)
4. Apollo 11 Science Instrument Still Shines, Space.com, 20 July 1999.
5. Picture of array of corner reflectors on the moon
6. Lunar Retroreflectors, of various kinds and nationalities, with pictures and explanations.

REFERENCES: (PIRA unknown.)

EQUIPMENT: Laser with baffle, hand-held corner reflector.

SETUP TIME: 5 min.