How does a laser measure the distance between Earth and the Moon? Answer - During the Apollo missions (11, 14 and 15) the astronauts have been placing retroreflector arrays on the lunar surface. Two Russian unmanned missions have deployed reflector arrays too, one failed completely probably due to being covered by dust and the other one seems to be less efficient than the Apollo reflectors. Short laser pulses are being sent to the reflectors, get reflected by the retro reflectors and then get received by the ground station. Counting the round trip travel time of the laser pulses directly gives the distance of 238,855 miles from Earth. Experiment: Why does the Moon shines at night? Materials: Dark room, bike reflector and flashlight. Process: In a lighted room show residents the bike reflector. Next, turn off the lights, make the room totally dark, and ask if the residents can see the bike reflector. Then turn the flashlight onto the bike reflector and ask residents if they can see the bike reflector. Result: T
he bike reflector represents the Moon and the flashlight represents the sun. The Moon shines as a result of reflected sunlight.