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.

27. Create Your Own Example:
Step 1: Draw a graph of a wave
Step 2: Draw a second wave that differs from the first
Step 3: Draw the graph of the wave that would result if you put wave 1 and wave 2 together

28. Do Now Get a piece of colored paper
Write a thank you note to a teacher, parent, family-member, or anyone who has helped you be successful in your education and reach your goals

29. Words Have Multiple Meanings
Date
Leaves
Engaged
Point
Right
Resonance

30. Resonance
Richness or significance, especially in producing a strong emotion
Physical Science Book:
An occurrence in which the natural frequency of a system is exactly in tune with a force applied to a system

31. What the heck does that mean???
Lets start with natural frequency
Describes how an object vibrates
If you pluck a guitar string 10 times and measure the frequency – the frequency of vibration will always be the same
Tuning forks each have a natural frequency in which they vibrate at

32. Tuning a Guitar
Musical instruments work by adjusting the natural frequency of vibrating strings or air to match musical notes
Tuning a guitar changes the natural frequency of a string by changing its tension

33. Back to Resonance
When the natural frequency matches the force applied causing a wave
Results in the amplitude of the oscillation growing
Example: Swing
Small pushes add up to a large amplitude of motion
By applying small pushes at a frequency matched to the natural frequency we create a large motion
Repeated pushes and natural motion creates resonance

34. Video Example

35. Activity to Investigate
Work in groups of 2-3
One person from each group needs to come up front and get the materials:
Graduated cylinder
Tuning fork
Mallet
Beaker of water
DO NOT MAKE A MESS!
Act like the YOUNG ADULTS I know you can be 

36. Do Now: What is the unit for frequency?
As wavelength of a wave increases, what happens to the speed of the wave?
What is the equation for the speed of a wave?

37. Objectives: Learning Intentions – Success Criteria –
Students will be able to explain and show understanding of material from the first half of the unit on the assessment
Success Criteria –
We will know we are successful when we can accurately demonstrate knowledge from the first half of the unit on the assessment

38. Questions?? Topics covered on quiz: What is a wave? 6 types of waves
Mechanical vs. Electromagnetic waves
Transverse vs. Longitudinal waves
Parts of a wave: crest, trough, node, amplitude, wavelength
Calculating speed of a wave

39. When finished… Turn in quiz on the stool up front
Pick up a reading from the text
Read and underline important points
Make a Frayer model of one of the key vocabulary words from the reading