Waves

Waves are a means by which energy travels.

There are many different types of waves. For example the waves on an ocean are physical waves caused mainly by wind. Light is an electromagnetic wave caused by excited electrons moving. Sound also moves in waves with the air particles moving backwards and forwards creating areas of different pressure.

Last week we looked at:

Reflection - when waves, whether physical or electromagnetic, bounce from a surface back toward the source. A mirror reflects the image of the observer.

and

Refraction - when waves, whether physical or electromagnetic, pass from one material into another they are deflected. The wave generally changes the angle of its direction because it's velocity changes. As it moves from a less dense to a more dense material it it bends towards the normal.

This week we are looking at a third property of waves:

Diffraction - when a wave goes through a small hole it's edges are bent and it flares out. Diffraction is a characteristic of waves of all types. We can hear around a corner because of the diffraction of sound waves. For instance, if a wall is next to you when you yell, the sound will parallel the wall. The wall may stop, but the voice doesn't; sound will almost turn the corner of the wall. This is diffraction.