If an airplane is flying faster than the speed of sound you actually hear something which happened later and then hear something which happened earlier!

What will you hear if a supersonic airplane flying over you? Here's an example of a sonic boom.

If you hear a sonic boom, can you point out the direction of the airplane just from hearing the sound?

This simulation might help you answer these questions

Applet courtesy of Professor Fu-Kwun Hwang, Dept. of physics, National Taiwan Normal University

How to play

• Press Start to start the animation. A listener is represented by an ear!
• You can press the left mouse button and drag it within the screen to change location of the listener
• The program draws sound wave paths to the listener
• The animation will be suspended when the sonic boom arrives at the listener
• Click the right mouse button to continue (if you have a Mac, press the Apple key while you press the mouse button)
• The color of the paths changes to blue
• The order in which the sound paths arrive at the listener are shown also
• You can change the ratio of airplane speed of airplane to sound speed and see the difference
• Press Reset for default values