Could someone tell me what sound barrier is and what it means to break the sound barrier (in really simple terms)?

Answer 1

http://hyperphysics.phy-astr.gsu.edu/HBASE/sound/soubar.html

Answer 2

Thanks :)

Answer 3

In the years before 1950, it was very difficult for airplanes to fly faster than the speed of sound because of shock waves that form in front of the wings and propellers that greatly increased the aerodynamic drag. Control of the airplane was also difficult because of instabilities that arise near the speed of sound. By going to swept-back wings and jet engines, and getting an extra boost by starting in a dive, it was possible to go faster than sound with the Bell X-1, the plane that Chuck Yeager flew. Nowadays is it no big deal for military jets and the SST to exceed the sound "barrier", but mopst planes still fly more economically below the speed of sound.