The Behavior of Waves

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

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

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”

4. Refraction Illustrations

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

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

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

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

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

10. Interference Illustrations

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

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.