in vacuum chamber, 2 thin lines each hangs a bell. ring 1 bell, measure temperature of the 2 bells. if bell 1 keeps ringing, its temperature should be increasing, then stay at maximum. bell 2 should feel gravity wave produced by bell 1 and heat up, the closer the hotter. 1/r^2 or you can say bell 1 gives heat radiation to bell 2 to heat it up? if both bells get hotter, that means gravitational wave is working?