properties of waves + units (need to add types)

What are longitudinal vs transverse waves

Longitudinal- vibrations of the wave are parallel to the direction of energy transfer

Transverse- vibrations of the wave are perpendicular to the direction of energy transfer

two examples of longitudinal and transverse waves?

Transverse- Light, Radio, Electromagnetic

Longitudinal- Sound, Shock

What is the frequency?

The frequency is the number of times a wave passes a point every second

What is the amplitude of a wave?

The height of the wave from midpoint to peak.

( maximum displacement from the equilibrium position - x-axis)

What is wavefront

It is created by overlapping lots of different waves. It's where all vibrations are in phase a d the same distance from the source

What is a time period?

The time taken or one complete wave to pass

What is the wavelength?

The distance from peak to peak

What is a vacuum?

A space with no particles

What do waves do?

Waves transfer energy from one place to another, without transferring matter

What is the equation for frequency and time period

F = 1 / T

units for frequency

Hz

what is the doppler effect

When a car is not moving, sound waves we receive are a series of evenly spaced wavefront → if car is moving, waveforms nomloner equally spread.

When a sound emitting object is not moving what sound waves do we detect

Constantbfrequency and wavelength

What if the sound emitting object is moving towards you

The wavefront get compressed so the sound increases in frequency (sounds higher pitched than when stationary)

What happens when a sound emitting object is moving away from you?

The wavefront gets stretched out so the sound decreases in frequency (sounds lower pitched than when stationary)

What is the change in frequency of the sound emitting object called - does it happen to all types of waves

Doppler effect, yes

can all waves be reflectad snd refracted?

All waves can be reflected and refracted. Angle of incidence = angle of reflection

What are sound waves

Longitudinal waves, produced by vibrating objects, can be reflected + refracted

Method for Light vs Sound

1. Get two people to walk at least 100m to the other end of field, person 1 measures distance walked with trundle wheel, will lower it - visual signal, person 2 makes a sound, pot and stick ( audio signal)

2. Everyone else stays at starting point with stop watches

3. Person 1 and 2 then create signals at the same time, the ones with sotpeatches will start when they see visual signal, and stop when they were audio signal

4. Repeat to get multiple readings

5. Find the mean

6. Use for u, a s=d/t

Method of Echo

1. A group will stand atkeast 50m from a large wall

2. One person will make audio sinal by clapping wooden blocks, everyone se will have a stop watch

3. They will then make the signal, everyone will start when they hear audio signal but stop when they hear the echo of the audio signal (reflected of large wall)

4. Repeat investigation

5. Find average of results

6. Use s=d/t equation.

7. THE DISTANDE TRAVELLED BY THE SOUND WILL BE DOUBKE THE DISTANDE BETWEEN THE GROUP AND WA,,

What is the key for the echo method

THE DISTANDE TRAVELLED BY THE SOUND WILL BE DOUBKE THE DISTANDE BETWEEN THE GROUP AND WALL

How does an oscilloscope display a sound wave, how? What does this let us see?

Used to provide an image of representation of a sound wave, converts the longitudinal sound wave to a transverse wave. Allowing us to see features such as waves amplitude and frequency more easilym

what feature of the oscilloscope trace is the amplitude

the distance from the equilibrium of the wave to the peak

How does the pitch of a sound relate to frequency of vibration of the source?

The pitch of a sound relates to frequency of vibration of the source

→ low pitch sound,low freq + long wavelength

→ high pitch sound,high freq + short wavelength

How does the loudness of a sound relate to the amplitude of vibration of the source

The loudness relates to the amplitude of vibration of the source,

Quiet sound - small amplitude

Loud sound - large amplitude

Order of species d of sound between solid, liquid and gas - fastest to slowest

Solid, liquid and gas

What does the speed of sound depend on

It depends of the material through it travels.

Equation for speed, distance and time.

S = d / t

What is the speed of sound in air

340 m/s

Name of equipment used to display sound waves

Oscilloscope

What is the range of human hearing

20→ 20,000 Hz

What are the axjs for an oscilloscope trace

|^ voltage → time

What does pitch depend on

Frequency

What does loudness depend on

Amplitude

What is the time base

The distance each square in the x-axis represents

Value to times for mega, kilo, centi and milli

Mega - 10^6 Kilo- 10³ Centi - 10^-2 Milli - 10^-3

Value to times for micro and nano

Micro - 10^-6 Nano -10^-9

formula for wave speed =

wave speed (v) = frequency (f) x wavelength (λ)

Method for frquency with an Osccilloscope

1. Connect the signal generator to the oscilloscope

2. alter the time base so you can see waveform

3. meaure time period of wave

4. calc freq of wave

5. repeat for differnt inout qualties

when galaxies move away from us they appear to have a red shift in color why?

the galaxies are moving away→ light waves are stretched → wavelength increases → red shift (doppler effct) → causing waves from objects moving away to shift to lower frequencies (red end of spectrum)

what color do galaxies appear when moving towards us

blue, other end of light spectrum

two other examples of doppler effect :

red shift : shifted towards red end of spectrum

plane sound: doppler effect

what does pitch depend on

frequency

what does loudness depend on

amplitude

what is the pitch

degreepf highlees ot lowness of a tone