A wave is a disturbance that carries energy from one place to another.

Types of waves

There are three main kinds of waves, although we will focus on just the first kind in this course:

1. Mechanical Waves - examples are water waves, sound waves, and waves on strings. The wave requires a medium through which to travel, but there is no net flow of mass though the medium, only a flow of energy.
2. Electromagnetic Waves - examples are light, x-rays, microwaves, radio waves, etc. They're just different frequency ranges of the same kind of wave, and they don't need a medium. Stay tuned for these next semester.
3. Matter Waves - waves associated with things like electrons, protons, and other rather tiny particles.

Another way to classify waves is to compare what the particles in the medium are doing to the direction the wave is traveling.

• Transverse Waves - the particles in the medium oscillate in a direction perpendicular to the way the wave is traveling. A good example is a wave on a string.
• Longitudinal Waves - the particles in the medium oscillate along the same direction as the way the wave is traveling. Sound waves are longitudinal waves.