1. on your foldable label each tab with the following:
**Look at board**
on your foldable label each tab with the following:
Interactions of Waves
Reflection
Refraction
Diffraction
Interference
Standing Waves
Doppler Effect
Practice Questions

2. Waves can interact with other objects and with each other
Interactions of Waves
Waves can interact with other objects and with each other

3. Interactions of Waves with objects
Reflection/Refraction/Diffraction

4. Reflection of waves
Definition: The bouncing back of a wave when it hits a surface through which it cannot pass
Light (an electromagnetic wave) and sound (a mechanical wave) waves can be reflected
Example: sonar

5. Reflection – we see ALL objects because light waves reflect (bounce) off of objects and into our eyes!

6. Refraction of waves
Definition: the bending of a wave caused by a change in its speed as it travels from one medium to another.
DRAW Refraction of light:

7. Refraction of waves
When white light hits a prism, the individual light waves change speed and bend at different angles, allowing each color to be seen.
***did the light wave speed up or slow down as it entered the prism?

8. Diffraction of waves
Definition - When a wave moves around a barrier or through an opening in a barrier, it spreads out.
Light waves diffract when they spread out after moving through the opening of a cloud. (DRAW in foldable!)
You can hear conversations in other rooms because sound waves travel through an open door, and spread out down the hallway

9. Interactions of Waves with each other
Constructive interference/
Destructive interference

10. INTERFERENCE
When several waves are in the same location, they combine to produce a single, new wave that is different from the original waves.
Interference can be constructive or destructive

11. CONSTRUCTIVE INTERFERENCE
Constructive interference occurs when waves combine to make a wave with a larger amplitude. Think of constructive interference as waves “helping each other” or adding energies
An example of constructive interference would be sound waves interacting from speakers at a concert

12. DESTRUCTIVE INTERFERENCE
Destructive interference occurs when two waves combine to make a wave smaller in amplitude. Think of destructive waves as subtracting their energies/cancel each other out
An example of destructive interference is sound canceling headphones

13. STANDING WAVES
When two waves interfere that have equal wavelength and amplitude, but travel in opposite directions, they make a standing wave that looks like the diagram to the right
The points in a standing wave that look pinched, are called nodes . Nodes are the places where waves have destructive interference, and cancelled each other out.

14. STANDING WAVES
The widest points in a standing wave are called antinodes – these are the points where wave have constructive interference, and maximum amplitude is reached

15. THE DOPPLER EFFECT
The change in frequency and pitch due to movement is called the Doppler Effect.
DOPPLER EFFECT HAS TO DO WITH PITCH ONLY!!!!!!!!!!!!
You can remember this by the name doPPler!! P stands for PITCH!!!!!

16. THE DOPPLER EFFECT
Pitch is determined by the frequency at which a sound waves strike your eardrum.
High frequency = high pitch
low frequency = low pitch
**what does this mean in terms of wavelength??

17. DOPPLER EFFECT
When the object or sound source is moving, the frequency of the wave changes because the motion of the source affects the wavelength
If an object is moving toward you the movement causes the wavelength to shrink/decrease – making frequency higher, making the pitch higher
(when an object is coming TOWARD you, you hear a HIGHER PITCH)

18. If an object is moving away from you, the movement stretches the wavelength, making it longer, and making the frequency lower.
(when an object is going AWAY from you, you hear a LOWER PITCH)

19. http://app. discoveryeducation

20. DOPPLER EFFECT
Who would hear a higher pitched sound? Why?

21. Constructive Interference Destructive Interference
Terms to Know
Reflection
Refraction
Diffraction
Interference
Constructive Interference
Destructive Interference
Standing Wave
Node
Antinode
Sound Wave
Vibration
Intensity/Loudness
Decibel
Pitch
Frequency
Hertz
Infrasound
Ultrasound
Doppler Effect