The Behavior of Waves

Reflection

• Reflection – when a wave strikes an object and bounces off of it• All types of waves can be reflected

Law of Reflection• The wave which strikes a surface is called the

incident ray• The wave that bounces off of the surface is

called the reflected ray

Law of Reflection – the angle of incidence is always equal to the angle of reflection

Refraction

• Refraction – the bending of waves caused by a change in its speed as it moves from one medium to another• The greater the change

in its speed, the more the wave bends

Light slows down – bends towards the normal

Light speeds up – bends away from the normal

How does a prism work?

1.) Light waves enter into prism and slow down.

2.) This causes the waves to bend

3.) The different colors of light bend different amounts so the colors are separated

Diffraction

• Diffraction – when an object causes a wave to change direction and bend around it

Diffraction and Wavelength• Amount of diffraction depends on the size of

the object the waves hit and the wavelength of the waves• If the object is smaller than the

wavelength the waves will bend around it• So sound waves which are larger will diffract much better than light waves which are much smaller

Absorption

• Waves can also be absorbed when they strike an object.• Energy is converted into thermal

energy • This is why wearing dark clothes in

the winter months keeps you warmer

Interference

• Interference – when two or more waves combine to form a new wave

Constructive Interference• Constructive interference – when two or

more waves add together• In transverse waves the crests will line up

with one another• In compressional waves the compressions

will line up with one another• The overall effect is to increase the

amplitude (energy) of the wave

Destructive Interference

• Destructive interference – waves subtract from one another when they overlap

Standing Wave

• A standing wave is a special type of wave pattern that forms when waves equal in wavelength and amplitude, but traveling in opposite directions, continuously interfere with each other

• The places where the two waves always cancel are called nodes.