1. The Behavior of Waves

2. 1. Reflections
Reflection – when a wave strikes an object and bounces off of it
ALL types of waves can be reflected
Example: light reflection in a mirror, sound reflection via an echo

3. 2. Law of Reflection Incident beam – beam striking the mirror
Reflection beam – beam that bounces off the mirror
Normal – line drawn perpendicular to mirror
***Angle of incidence is always equal to the angle of reflection

4. 3. Refraction
Bending of a wave caused by a change in the wave’s speed as it moves from one medium to another
The greater the change (up or down) in speed, the more the wave bends.
When a wave passes into a medium and speeds up the wave is refracted AWAY from the “normal”
When a wave passes into a medium and slows down the wave is refracted TOWARD the “normal”

5. 4. Refraction Illustrations

6. 5. Diffraction
Diffraction occurs when an object causes a wave to change direction and bend around the object
Difference is diffraction occurs when a wave pass around an object while refraction is when a wave goes through an object

7. 6. Amount of Diffraction Depends on wavelength and size of obstacle
Less diffraction if the wavelength is smaller than the obstacle
More diffraction if the wavelength is the same size or larger than the obstacle

8. 7. Interference
When two or more waves overlap and combine to form a new wave
Two types: constructive and destructive
Occurs in both transverse and compressional waves

9. 8. Constructive Interference
Waves add together
Amplitude (sum of both crest, compressions, troughs, or rarefactions)
“In Phase”
Sound - louder

10. 9. Destructive Interference
Waves subtract from each other as they overlap
Amplitude is the difference of the waves
“Out of Phase”
Sound - reduces

11. 10. Interference Illustrations

12. 11. Standing Wave
Occurs when waves with equal wavelengths and amplitudes continuously interfere with each other
Node- place where waves cancel each other out
Wave vibrates between the nodes
Example: musical instruments

13. 12. Resonance
Resonance =The ability of an object to vibrate by absorbing energy at its natural frequency.
Remember that the amplitude of a wave increases as the energy it carries increases.
An object vibrates more strongly as it continues to absorb energy at its natural frequency.
***If enough energy is absorbed, the object can vibrate so strongly that it breaks apart.