Chapter 17- Physical Science

These properties depend on factors such as your age and the health of your ears

loudness, pitch

A disturbance in matter that carries energy from one place to another is called a(n) _______________

mechanical wave

The material through which a wave travels is called a(n) _________________

medium

Hammer, anvil, and stirrup are located here

middle ear

Sound vibrations are amplified

middle ear

Maximum displacement of a wave

Amplitude

What creates a mechanical wave?

An energy source causes a vibration to travel through a medium.

A unit used to compare sound intensity levels

Decibel

Occurs when a wave encounters an object r opening that is close in size to its wavelength

Diffraction

An apparent change in frequency of a sound source that moves relative to an observer

Doppler Effect

T/F: A wave diffracts more if its wavelength is small compared to the size of an opening or obstacle.

False

T/F: Mechanical waves can travel through empty space.

False

How is wavelength determined for a longitudinal wave?

For a longitudinal wave, wave length is the distance between adjacent compressions or rarefactions.

Occurs when waves overlap

Interference

Why is an ocean wave classified as a surface wave?

It travels along a surface separating two mediums, air and water

A point of no displacement in a standing wave

Node

The time required for one complete wave cycle

Period

Area where parcels in a medium are spread out as longitudinal wave travels through it

Rarefaction

Write a formula you can use to determine the speed of a wave

Speed= Wavelength X Frequency

Type of mechanical wave whose direction of vibration is perpendicular to its direction of travel

Transverse

T/F: A periodic motion repeats at regular time intervals.

True

Distance from one point to the next identical point on a wave

Wave length

The maximum displacement of a medium from its rest position

amplitude

State the letter of the characteristic used to classify a mechanical wave. a. the height of its crest b. the depth of its trough c. the way it travels through a medium d. the type of medium through which it travels

c

When a longitudinal wave carries energy through a spring, the area where the coils of a spring are closer together than they would be in the rest position is called a(n) __________

compression

The highest point of a wave above the rest position is the ___________ and the lowest point below the rest position is the __________

crest; trough

Theaters are designed to prevent "dead spots" where the volume is reduced by __________________ of reflected sound waves

destructive interference

Sound is reproduced by converting _______________ back into sound waves

electronic signals

T/F: The three main types of mechanical waves are water waves, longitudinal waves, and surface waves.

false

T/F: Ultrasound is sound at frequencies that are lower than most people are capable of hearing

false

The number of complete cycles in a given period of time is the ___________ of a periodic motion

frequency

For a stationary observer, as a moving sound source approaches, the observer will first hear a(n) _____________ frequency of sound and then a(n) _____________ frequency as the source moves away

higher, lower

Nerve endings send signals to the brain

inner ear

This property is measured in units called decibels

intensity

A wave in which the vibration of the medium is parallel to, por in the same direction as, the direction in which the wave travels is called a(n) _________

longitudinal wave

P wave

longitudinal wave

Rarefactions with particles that are spread out

longitudinal waves

This property is a physical response to the intensity of sound

loudness

Sound is gathered and focused here

outer ear

The eardrum is located at the boundary between these two regions of the ear

outer ear, middle ear

the time required for one cycle, a complete motion that return to its starting point, is called the ____________

period

This property is the frequency of a sound as your ears perceive it

pitch

These properties are affected by the length of tubing in a musical instrument

pitch, frequency

The response of a standing wave to another wave of the same frequency is called ________________

resonance

At certain frequencies, interference between a wave and its reflection can produce a(n) ___________.

standing wave

An ocean wave

surface

A wave that travels along a boundary separating two mediums

surface waves

What variables can cause stye speed of a wave to change?

the speed of a wave can change if it enters a new medium or if variables such as temperature and pressure change.

Direction of travel is perpendicular to vibration direction

transverse wave

It is a wave that causes the medium to vibrate at right angles to the direction in which the wave travels

transverse waves

lowest point of a wave below the rest position

trough

T/F: A rarefaction is a region in a longitudinal wave where particles of a medium spread out.

true

T/F: Destructive interference can result in wave displacements that are above the rest position

true

T/F: If a standing wave occurs in a medium at a given frequency, another standing wave will occur if this frequency is doubled.

true

T/F: Many musical instruments vary pitch by changing the frequency of standing waves.

true

T/F: Rarefaction always involves a change in the speed and direction of a wave

true

T/F: Reflection occurs when a wave bounces off a surface that it cannot pass through

true

T/F: Solids, liquids, and gases all can act as mediums for waves.

true

T/F: The Doppler effect is a change in sound frequency caused by motion of the sound source, motion of the listener, or both.

true

T/F: The speed of a wave equals its wavelength divided by its period

true

occurs when two or more waves overlap and combine

wave interference

The distance between a point on one wave and the same point on the next cycle of the wave is called ___________

wavelength