if you shout into the grand canyon your voice travel at the speed of sound (340m/s) to the bottom of the canyon. how depp is the grand canyon at a spot where someone at the bottom can hear your voice 3.5 seconds after you shout
It takes 3.5 seconds for the sound to reach the bottom of the canyon and then return to the top. So it takes half the time to reach the bottom, or 1.75 seconds.
