Physics - Ch.3: Describing Sound Waves

What are the 7 Parameters of Sound Waves?

• Period

• Frequency

• Amplitude

• Power

• Intensity

• Wavelength

• Speed

Period:

• Definition

• Units

• Determined By

• Adjustable 

• Time it takes a wave to vibrate a single cycle or time from start of one cycle to the start of the next cycle

• Time; microseconds, seconds, hours, or days

• Sound source

• No

Frequency:

• Definition

• Units

• Determined By

• Adjustable

• Number of particular events that occur in a specific duration of time or number of cycles that occurs in one second

• Per seconds; Hertz

• Sound source

• No

Sound Waves Frequency:
(what are their ranges in #?)

• Infrasound

• Audible Sound

• Ultrasound

• < 20 Hz

• Between 20 Hz - 20 kHz

• > 20 kHz

What is the Relationship Between Frequency & Period?

• Inversely related; frequency increases, period decreases

What is the Special Relationship Between Period & Frequency?

• Reciprocal

• = 1

What are the “Three Bigness Parameters”?

• Amplitude 

• Power

• Intensity

Amplitude:

• Definition 

• Units

• Determined By

• Adjustable 

• “Bigness” of a wave; difference between max value and average or minimum value and average value of acoustic variable

• Any acoustic values: pressure (pascals), density (g/cm3), and particle motion (cm, in, any distance)

• Initially sound source, then decreases as sound propagates through body

• Yes 

What is the Difference Between Amplitude & Peak-to-Peak Amplitude?

• Amplitude = baseline to top of peak

• Peak-to-Peak Amplitude = minimum (below baseline) to maximum (top of peak)

Power:

• Definition

• Units

• Determined By

• Adjustable

• Rate of energy transfer or rate at which work is performed

• Watts

• Initially by sound source, then decreases as sound propagates

• Yes

What is the Relationship Between Amplitude & Power? + What is the Mathematical Proportion Between them?

• Directly related; amplitude increases, power increases

• Squared 

Intensity:

• Definition 

• Units 

• Determined By

• Adjustable 

• Concentration of energy in a sound beam; how the power in a wave spreads/ distributed in space

• Watts/square centimeter; W/cm2

• Initially sound source, then changes as it propagates through body

• Yes

What is the Relationship Between Intensity & Power?
What is the Relationship Between Intensity & Amplitude?

• Directly proportional; intensity increases, power increases 

• Directly proportionally squared; amplitude is doubled, intensity increases four times its own value

Wavelength: 

• Definition

• Units

• Determined By

• Adjustable

• Distance or length of one complete cycle

• Length; mm, meters, etc.

• Both; sound source and medium

• No

What is the Difference Between Wavelength & Period?

• Wavelength = length/ distance of a single cycle

• Period = time it takes to complete a single cycle

• Differenciated by their units:
  > Wavelength = distance
  > Period = time

What is the Relationship Between Wavelength & Frequency?

• Inversely related; wavelength increases, frequency decreases

Propagation Speed:

• Definition 

• Units

• Determined By

• Adjustable

• Rate at which a sound wave travels through a medium

• Meters per second; any distance/time

• Medium

• No

What is the Speed of Sound in Soft Tissue? (name 3 units)

• 1,540 m/s

• 1.54 mm/milisecond

• 1.54 km/s

What Characteristics of a Medium Determine the Speed of Sound in that Medium? (name 2)

• Stiffness

• Density

Stiffness:

• Definition

• How does it affect speed? + What is their relationship?

• Ability of an object to resist compression

• Stiffness and speed are directly related; stiffness increases, speed increases

Density:

• Definition 

• How does it affect speed? + What is their relationship?

• Relative weight of a material 

• Inversely related; density increases, speed decreases

Between Stiffness and Density, Which One Has the Greatest Affect on Speed?

• Stiffness