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Ch. 14 - Waves & Sound I. Characteristics of Waves Waves Transverse waves Longitudinal waves Measuring waves

Ch. 14 - Waves & Sound I. Characteristics of Waves Waves Transverse waves Longitudinal waves Measuring waves

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Page 1: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

Ch. 14 - Waves & Sound

I. Characteristics of Waves Waves Transverse waves Longitudinal waves Measuring waves

Page 2: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

A. Waves

Wavesrhythmic disturbances that carry energy through

matter or space

Mediummaterial through which a wave transfers energysolid, liquid, gas, or combinationelectromagnetic waves don’t need a medium

(e.g. visible light)

Page 3: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

A. Waves

Two Types:

Longitudinal Transverse

Page 4: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

B. Transverse Waves

Transverse Wavesmedium moves

perpendicular to the direction of wave motion

Page 5: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

B. Transverse Waves

Wave Anatomy

crests

troughswavelength

wavelength

amplitude

amplitude

corresponds to the amount of

energy carried by the wave

nodes

Page 6: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

C. Longitudinal Waves

Longitudinal Waves (a.k.a. compressional)medium moves in the same direction as wave

motion

Page 7: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

C. Longitudinal Waves

Wave Anatomy

rarefaction

compression

wavelength

wavelength

Amount of compression corresponds to amount of energy AMPLITUDE.

Page 8: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

D. Measuring Waves

Frequency ( f )

# of waves passing a point in 1 second

Hertz (Hz)shorter wavelength

higher frequency higher energy

1 second

Page 9: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

D. Measuring Waves

Velocity ( v )speed of a wave as it moves forwarddepends on wave type and medium

v = × f v: velocity (m/s)

: wavelength (m)

f: frequency (Hz)

Page 10: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

Sonic Boom: occurs when a jet flies

faster than the speed of sound due to compressions waves that stack up until the molecules in the wave

explode away from the source.

http://youtu.be/gWGLAAYdbbc

Page 11: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

Doppler Effect

As an ambulance comes toward you, the wavelengths are compressed in front of the ambulance (shorter wavelength leads to higher pitch).

http://www.youtube.com/watch?v=imoxDcn2Sgo

http://youtu.be/h4OnBYrbCjY

Page 12: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

Doppler Effect diagram

Page 13: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

Words associated with waves that you should

know:

http://youtu.be/mh3o8gUu4AE

15 minute video

Page 14: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

Standing Wave

Occurs when there is continuous interference of equal but opposite

amplitude. The wave appears to be standing still.

http://youtu.be/RUpjYDteYcg

https://www.youtube.com/watch?v=18BL7MKjtZM

Page 15: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

WORK:v = × f

v = (3.2 m)(0.60 Hz)

v = 1.92 m/s

D. Measuring Waves

EX: Find the velocity of a wave in a wave pool if its wavelength is 3.2 m and its frequency is 0.60 Hz.

GIVEN:

v = ?

= 3.2 m

f = 0.60 Hz

v

f

Page 16: Ch. 14 - Waves & Sound I. Characteristics of Waves  Waves  Transverse waves  Longitudinal waves  Measuring waves

WORK: f = v ÷

f = (5000 m/s) ÷ (417 m)

f = 12 Hz

D. Measuring Waves

EX: An earthquake produces a wave that has a wavelength of 417 m and travels at 5000 m/s. What is its frequency?

GIVEN:

= 417 m

v = 5000 m/s

f = ?

v

f