1. Thurs. Mar. 6 Do Now:
Circle the type of wave that needs a medium through which to travel:
Mechanical or Electromagnetic 
A wave has a wavelength of 8m and a frequency of 4 Hz. What is the wave’s speed? ________ 
Look at the two waves below. Circle the one with the greatest wavelength.

2. Students will be able to –
Learning Goals:
Students will be able to –
Explain the 4 ways in which waves interact
Illustrate the 4 types of wave interactions and provide examples of each

3. Activity:
You are going to investigate the different ways that waves interact with one another.
Each person needs to fill out a chart based about the 4 types of interactions:
Refraction
Reflection
Diffraction
Absorption

4. Reflection When waves strike an object and bounce off of it Examples
Mirror
Echos

5. Refraction
A wave travels from one medium to another so it changes speed and bends
Examples
Things under water
Prisms bending white light into colors

6. Diffraction Waves bend around a barrier Examples
Waves bend around rocks in the ocean

7. Absorption Waves can be absorbed as they pass through objects
Amplitude gets smaller as it passes through material
Example:
Sponge absorbing water waves
Sunglasses have dark light that absorbs light

8. Activity Continued:
Once your chart is filled in you need to find your group and receive your assigned interaction
Your group will make a poster about the interaction including
Definition
Illustration
Examples

9. Do Now: What do you think happens when two waves bump into each other?
Do you think a wave can stand still?

10. Students will be able to –
Learning Goals:
Students will be able to –
Define constructive and destructive interference
Classify standing waves, interference and wave behaviors in examples

11. Label amplitude:

12. Label the Wave Behavior:

13. Label the Wave Behavior:
C: ____________________
D: ____________________

14. Wave Interference
Two or more waves overlap and combine to form a new wave

15. Examples of Interference:
es/interference/waveInterference2/WaveInterf erence2.html

16. Constructive Interference
When does it happen?
When waves are on the same side and add together
Same side = in phase
Crest adds to another crest
What happens to the amplitude?
Becomes larger

17. Destructive Interference
When does it happen?
Waves on opposite sides add together
Opposite sides = out of phase
Crest and trough meet
What happens to the amplitude?
Becomes smaller

18. Interference
Constructive
Destructive

19. Example – Sound Interference:
The sound from two speakers meeting and amplifying the sound is an example of _______________________ interference.
The sound from two speakers meeting and canceling out is an example of _________________________ interference.

20. Example – Light Interference:
The light from two sources meeting and amplifying the light is an example of ___________________ interference.
The light from two sources meeting and canceling each other out is an example of __________________ interference.

21. Standing Waves:
Occurs when a wave is trapped in one spot between boundaries

22. Practice on Your Own:
Complete the practice portion of today’s packet with a partner

23. Answers:
The bending of a wave caused by a change in speed when moving from one medium to another.
The reason that objects under water appear to be closer to the surface than they really are.
The bending of a wave as it moves around an obstacle.

24. Answers Continued:
What happens to sound waves that causes us to hear an echo?
A light or sound wave being bounced back from a surface.
What happens when water waves bend around rocks in the ocean.

25. Answers Continued:
What happens to sound waves in a concert hall that makes some areas appear louder and some areas are “dead spaces”?
When trying to spear a fish in water, a person needs to take into account the way light bends as it moves from water into air, which is called—
What happens to light waves reflecting off of a layer of oil that creates the different colors?

26. Answers Continued:
Two waves reflect and interfere so perfectly that crests meet crests and troughs meet troughs.
What happens to light waves that allows us to see ourselves in a mirror?
Two or more waves overlap and combine to form a new wave.