Alright we did a lab using the speed of sound we were suppose to able to calculate the temperature outside. v = 332 +0.6T So this is what we did, one person hit two blocks together twenty times at an equal pace. The timers start when the person first hits the block together and stops when the last echo is heard. The distance from the wall and back is 200m So the times we got were 23.40s, 23.28s Then I calculated the average total time and average time for each echo cycle. Which is 1.167s So Speed = Distance / Time for each cycle Right? Speed = 200m/1.167s? If I do this, I end up with a negative temperature. So then did this, Speed = Distance/ Half of the time for each cycle. Speed = 200m/0.5835s By doing this I got the right temperature. Can anyone explain to me why I needed to divide the time for each cycle by two?