Chapter 8.3 Vocabulary

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Chapter 8 and 9
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Chapter 8.3 Vocabulary

• Reflection
• Refraction
• Diffraction
• interference

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Reflection of Sound

• Echo- reflected sound
• Depends on the surface of the reflection

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Echolocation

• Process of sound waves used to find objects
• Bats, whales, dolphins
• Sonar used in depth finders, oceanographers (map
  the ocean floor), navigators

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Ultrasounds

• Uses echos to see inside the body

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Question

• Describe places you think you would hear an echo?
• Is this reflection or refraction?

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Diffraction

• How sound waves travel around barriers or through
  openings
• You can hear low frequencies around obstacles
  better than high frequencies because of the
  larger wave length
• The thunder from a close bolt of lightning will
  be experienced as a sharp crack, indicating the
  presence of a lot of high frequency sound. The
  thunder from a distant strike will be experienced
  as a low rumble since it is the long wavelengths
  which can bend around obstacles to get to you.
  There are other factors such as the higher air
  absorption of high frequencies involved, but
  diffraction plays a part in the experience.

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Question

• When you are in a classroom, you can sometimes
  hear voices from the hallway even when you cannot
  see who is talking. Explain how this is possible.

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Interference of sound

• Waves overlapping
• Constructive interference causes louder volume
• Destructive interference cause sound to be
  cancelled out or decrease in volume

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Shock WavesCompression of sound waves- going
faster than the speed of sound
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Jet fighter planes with conical shock waves made
visible by condensation.
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Chapter 9

• Reflection
• Refraction
• Diffraction
• Interference

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Light

• Electromagnetic Wave (EM)
• Electromagnetic Spectrum which is arranged from
  long wave lengths to short wave lengths.
• Long wave lengths low frequency
• Short wave lengths high frequency

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• Decreasing wavelength / Increasing Frequency
• Radio waves
• Microwaves
• Infrared
• Visible light
• Ultraviolet
• Xrays
• Gamma Rays

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Reflection of Light-bouncing off an object
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Refraction of Light- bending of a wave
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Refraction and Reflection of Light
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Quiz

• Where does the light of moon come from?
• Explain how colors are separated in a rainbow.

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Diffraction of Light- bending of light around
barriers
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Interference of Light
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Constructive and Destructive Interference of Light