We just learned about Sound Waves.
When sound travels through the air, it moves very very fast, about 760 miles per hour!
That's faster than you can see, faster than you can run, and faster than any normal car you drive on the street!
Jet airplanes can go faster than the speed of sound, and when they get past that speed they make a big noise called a sonic boom.
Going faster than the speed of sound is called breaking the sound barrier.
(from: wikipedia - sound barrier
The first person to break the sound barrier in a jet was Chuck Yeager in the Bell X-1 jet on October 14, 1947.
(from: wikipedia - chuck yeager)
