There are many ways waves act and interact. What is the difference here?› When we are discussing interaction of

waves we need to know the difference between reflection, refraction, interference, diffraction, and so.

Reflection: is when a wave hits a surface of a medium that it cant go through and bounces back. › Can anybody give me some examples of

reflection that occur in everyday life? Looking in the mirror Sunlight glare from the hood of your car.

› Law of reflection: states that the angle of incidence equals the angle of reflection

Refraction : is the bending of waves as they enter a new medium at an angle. › Example. Who in here rides a skateboard?

Have you ever been riding down the sidewalk and gotten to close to the grass and had one of your front wheels go into the grass, what happened? Your skateboard turned into the grass because of

the change in speed of your front wheels. The same thing happens with waves.

Refraction only happens when a wave enters a medium at an angle. Because then one side of the wave enters the medium first, slowing it down, causing the wave to bend. › Have any of you put a stick into water and

seen it “bend” or tried to pick something up in water and its not as close as it seems. Why does a rainbow have all of those colors?

Because the white light is bent as it enters the water droplet.

Diffraction : the bending of waves as they move around a barrier or pass through an opening. › Sometimes waves bend around stuff they

cant get through, like an Island in the ocean, or a rocky point in a lake.

What do you think of when we say interference?› What is wave interference?

Wave interference is : the interaction between two or more waves when they meet and take up the same space. There are two types of interference. Constructive and distructive

Constructive interference: is when waves combine to make a wave with a larger amplitude. › These waves help each other. After they

meet they continue as though they had never meet.

Destructive interference :is when two waves combine to make a wave with a smaller amplitude. › These type of waves subtract their energy

from each other, these type of waves basically cancel each other out.

What is a seismic wave?› These are waves produced by Earthquakes.

Seismic waves include P waves, S waves, and surface waves.

› P waves are longitudinal waves; P waves (or primary waves) move faster than the others. These waves are made up of compression and rarefactions of rock. These waves compress and expand the ground like a spring toy as they move through it.

S waves; are transverse waves with crest and troughs. These are know as S waves or secondary waves. They shake the ground up and down and side to side as they move through it. These type of waves can’t travel through liquids. › This is how we know what the composition

of the core is, because scientists directly on the opposite side of the Earthquake will only register P waves.

Surface waves are a combination of transverse and longitudinal waves, that travel along the surface of the medium. These are the slowest of the seismic waves. › surface waves are what cause tsunamis

when an Earth quake happens in the Ocean.