I’m glad there are people who actually can understand stuff like this because it was a major brain-strain just to try to understand putting the clock in an elevator, let alone how the light would work while it was moving. ;^)
But I DO give myself props for realizing, right AFTER I pressed the post button, that the one travel time would be lengthened and the other shortened, so I guess I’m not a total dunce at it. But then shaking the clock up and down vigorously came to mind and I soon was in the throes of a massive brain fart just trying to imagine that. 8^O
I’m gonna give up before my head explodes.
I was actually already familiar with the question because an almost identical thing comes up in the famous Michelson-Morley Experiment.
See episode 41 if interested: (it’s free to watch the entire series online)
In episodes 42 and 43, there are excellent animations and explanations of the discussed light clock.
41. The Michelson-Morley Experiment
In 1887, an exquisitely designed measurement of the earth’s motion through the ether results in the most brilliant failure in scientific history.
42. The Lorentz Transformation
If the speed of light is to be the same for all observers, then the length of a meter stick, or the rate of a ticking clock, depends on who measures it.
43. Velocity and Time
Einstein is motivated to perfect the central ideas of physics, resulting in a new understanding of the meaning of space and time.
44. Mass, Momentum, Energy
The new meaning of space and time make it necessary to formulate a new mechanics.
http://www.learner.org/resources/series42.html