This unit introduces students to some general concepts of astronomy. Topics include geocentric versus heliocentric theories of the solar system and how they explain the sun's movements, sidereal days versus solar days,...

The wave simulator, created by Paul Falstad, can be used to create a wide range of demos with reflectors, lenses, cavities, and point sources. Common examples such as multiple source and multiple slit interference,...

This web page explains the physics of sonic shock waves. Text and animations describe and illustrate the wavefronts of sound from a moving point source for the cases of motion equal to, less than, and greater than the...

This site, authored by Daniel A. Russell of Kettering University, offers an animation that shows the formation of shockwaves from waves generated by a moving source. Photos show shockwaves of a bullet, an airplane, and a...