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Waves and Sound. What are Waves?. Describe a Wave:. Think about an ocean wave Now describe it. Waves. Rhythmic disturbances that carry energy through matter or space Ocean Waves – energy through water Earthquakes – energy through Earth Both travel through a medium
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Describe a Wave: • Think about an ocean wave • Now describe it
Waves • Rhythmic disturbances that carry energy through matter or space • Ocean Waves – energy through water • Earthquakes – energy through Earth • Both travel through a medium • Medium – a material through which a waves transfers energy
Two Types of Waves • Transverse Waves – medium moves at right angles to the direction the wave travels • Compressional or Longitudinal Wave • A type of wave where matter vibrates in the same direction as the wave travels
Transverse Wave The wave is traveling in this direction Rest Position
Amplitude • Amplitude corresponds to the amount of energy carried by a wave • Large amplitude = Large amount of energy • Small amplitude = Small amount of energy
Wave Frequency • The number of wave crests that pass one place each second. • Expressed in Hertz (Hz) • One hertz = One wave per second • How do you increase the wave frequency? • Rope demonstration • What happens to the wavelength when the frequency increases? • The wavelength decreases!!!!! Meaning Increased wave frequency means decreased wavelength
Calculating Wave Frequency • Velocity = Wavelength x Frequency OR V = λ x ƒ Example: A wave is generated in a wave pool at a water park. The wavelength is 3.2 m. The frequency of the wave is 0.60 Hz. What is the velocity of the wave? V = λ x ƒ V = ? λ = 3.2 m ƒ = 0.60 Hz V = 3.2 m x 0.60 V = 1.92 m/s Why m/s? Remember 1 Hz = 1 wave/second or m x 1/s or m/s