The document discusses different types of wave interactions including reflection, scattering, refraction, diffraction, absorption, and interference. Reflection causes waves to bounce back at the same angle they hit an object. Scattering is a type of reflection where waves reflect in many directions after colliding with matter. Refraction causes waves to bend when moving between materials with different propagation speeds. Diffraction occurs when waves bend around barriers or through openings. Absorption transfers energy from waves to objects. Interference involves overlapping waves that can either constructively or destructively combine by increasing or decreasing amplitude.
2. Waves All Around Us
Imagine you just spent a day at the beach
with your family. You had a blast playing in the
ocean, laying out in the sun, listening to music
and talking with your family. When you go
back to the condo, you heat up some pizza in
the microwave and turn on the TV.
Can you name all the different waves that
were present in your day on the beach?
3. Standard
S8P4. Students will explore the wave
nature of sound and electromagnetic
radiation.
B. Describe how the behavior of light
waves is manipulated causing reflection,
diffraction, refraction, and absorption.
4. Review
From the list of waves you just named, can
you identify whether it is electromagnetic or
mechanical?
What is the difference between
electromagnetic waves and mechanical
waves?
Which one needs a medium?
What is a medium? Name 3.
Which one causes vibrations?
6. Reflection
Waves bounce back
All waves can be reflected
We can see objects because of the visible
light waves that are bounced off of them
Waves bounces back at the same angle
as it hits the object
Angle of incidence
(original wave)
Angle of reflection
(bounce back)
7. Scattering
Scattering
A type of reflection
Waves collide with matter and reflect in many
different directions
Blue sky shortest wave length of visible light
scattered by particles
in the atmosphere
8. Refraction
Wave bends as it is transmitted
Due to different wave speeds in different
mediums
gas to solid, gas to liquid
Causes optical illusions
9. Refraction
Rainbow
When white light waves separate by refraction,
we see colors
10. Diffraction
Most times waves travel in
a straight line
Can bend around a barrier
Edges of the object are blurry
Example eclipse, x-ray
Can bend through an opening
Sound waves are much longer
than light waves
Sound waves bend more
11. Absorption
Absorption
Transfer of energy to an object
light to heat
light to chemical (by plants with photosynthesis)
light to battery to electrical (by solar panels)
Soaks up waves
Makes waves dimmer
loss of energy
12. Interference
Overlapping waves
Share space
Either increases amplitude constructive
The thump from the car stereo next to yours.
Or, decreases amplitude destructive
You may not hear the person sitting two seats
away from you when the cafeteria is crowded.
13. Constructive interference
happens when waves add up to make a
larger amplitude.
Suppose you make two wave pulses on a
stretched string.
One comes from the left and the other
comes from the right.
When the waves meet, they combine to
make a single large pulse.
15. Destructive interference
What happens when one pulse is on top
of the string and the other is on the
bottom?
When the pulses meet in the middle, they
cancel each other out.
During destructive interference, waves
add up to make a wave with smaller or
zero amplitude.