A sine wave is a curve, a continuous function with this shape:

This is a picture of a sine wave.

All waves can be made by adding up sine waves. The sine wave has a pattern that repeats. The length of this repeating piece of the sine wave is called the wavelength. The wavelength can be found by measuring the length or distance between one peak of a sine wave and the next peak. The wavelength can be found in many other ways too. view more...