michelson-morley experiment: a celebrated experiment conducted by Albert Michelson and Edward Morley; their failure to detect any influence of the earth's motion on the velocity of light was the starting point for Einstein's theory of relativity
experiment: the act of conducting a controlled test or investigation
explosive trace detection: a system for screening luggage in airports; an agent passes a swab around or inside luggage and then runs the swab through a machine that can detect trace amounts of explosives