WAVES & SOUND REVIEW

This is a demonstration of what wave phenomenon…

Resonance

Can sound waves travel in a vacuum?

NO, they need a medium to travel through.

The distance between one waves crest and the next waves crest is called a ___________.

wavelength

For each second you count between lightning and the thunder it produces, how far away does it mean the lightning is from you?

340 meters

About 1/5th of a mile Or about 1/3rd of a kilometer

Noise cancelling headphones are an example of ________ interference.

Destructive

What causes a tsunami?

An underwater earthquake OR a massive landslide

If an ambulance is headed toward you the frequency of the sound waves coming toward you is ________ than normal.

Higher frequency

Shorter wavelength

The frequency of the sound coming from that same ambulance would be ________ than normal as it moves a way from you

Lower frequency

Higher wavelength

A wave travels a distance of 20 meters in a time of 4 seconds, what is the speed of the wave?

5 m/s

Which of these would sound travel the fastest through

Salt water Fresh water A wood cabinet A steel beam

Steel beam, because it is the most rigid

Is there sound in outer space?

NO, space is a vacuum and sound needs a medium to travel through

On a standing wave, the points that do not move are referred to as…..

Nodes

The number of times a wave vibrates each second is referred to as _______

frequency

The amount of time it takes each wave to pass is referred to as _______

Period

What type of wave is a sound wave?

Longitudinal wave

Waves in the ocean are what type of wave

Transverse

What is the proper unit for frequency?

Hertz

An oceanic depth-sounding vessel surveys the ocean bottom with ultrasonic sound that travels 1530 m/s in seawater, and finds a 10-second time delay of the echo to the ocean floor and back. The ocean depth there is

7650 meters

Beats are produced by two tuning forks that are sounded together, if one tuning fork has a frequency of 300 Hz and the other has a frequency of 305 Hz, what will be the frequency of the beats they produce?

5 Hz

Difference between frequencies

What destroyed the Tacoma Narrows bridge?

Resonance/ Standing Wave A standing wave was created when the

bridge resonated at its natural frequency as caused by the wind.

A 680 Hz sound wave that travels through air at a speed of 340 m/s would have a wavelength of____?

.5 meters

V = fλ So λ = v/ f or 340 / 680

12 full waves pass a dock in a time of 6 seconds.

A) what is the frequency of the waves?

B) What is the period of the waves

A) 2 Hz

B) .5 seconds

A skipper on a boat notices wave crests passing the anchor chain every 6 seconds. The skipper estimates the distance between crests at 30 m. What is the speed of the water waves?

In what kind of situation(s) would the doppler effect occur?

If a source of sound waves is moving toward you or away from you

If the frequency of a set of waves is increased, what will happen to wavelength?

It will go down

Inverse relationship

What of these wave properties determines the pitch of a sound wave?

Frequency Wavelength Period Speed

Frequency

High frequency high pitch

What is the source of all wave motion?

Vibration

A wave created by shaking a rope up and down is called a ______ wave.

Transverse

A wave has a wavelength of 1.5 meters. During a single period this wave has travelled how far?

1.5 meters

The amplitude of a wave is 3.0 meters, the top to bottom distance of the disturbance would be

6 meters

What property of a wave determines loudness?

Amplitude

Two waves that are in-phase with each other will undergo _______ interference.

Constructive

New larger wave will be produced Amplitudes add together

The phenomenon of ‘beats’ results from which of these

Interference Diffraction Frequency modulation resonance

interference

T or F. We would hear a sonic boom the instant a supersonic plane flew overhead.

False, it would be after the plane was directly overhead because the planes sound is trailing it

T or F. Resonance occurs when an object vibrates at its natural frequency

True

Every elastic object has its own natural frequency, when it vibrates at that frequency a large increase in amplitude will happen

A certain ocean wave has a frequency of 10 hertz and a wavelength of 3 meters. What is the wave’s speed?

30 m/s

The period of a wave is 8 seconds, what is its frequency?

1/8 Hz

How do we use the Doppler Effect to tell us that the universe is still expanding?

All galaxies are ‘red-shifted’ meaning they have longer wavelengths of light, this tells us they are all moving away from us…. Universe is expanding

If you have created a standing wave with a slinky and increase the frequency with which you are shaking the slinky what will happen to the number of waves in the slinky?

Number of waves will increase

Wavelength of each wave will decrease more waves crammed into the same length

The regions in between the compressed regions of a sound wave are called _________.

Rarefactions

The amplitude of a water wave is .5 meters. If a raft has one full wave pass under it… through how much distance will it vibrate?

2 meters

4 amplitudes

How is a sonic boom formed?

Something moving faster than the speed of sound

What other than a jet-powered vehicle can create a sonic boom?

Crack of a whip

What does ‘ultrasonic’ mean?

Sound waves that have a frequency higher than that which is audible >20,000 Hz.