Physics -science

what are waves?

oscillations or vibrations

what do waves do?

transfer energy

what is wavelength

the distance between a point of a wave to the same point on the next wave

what is the top of a wave called?

peak/crest

what is the trough?

the bottom of a wave

amplitude

the height of the wave.

frequency

the number of waves that travel past a point every second

what is frequency measured in?

Hertz

longitudinal waves

oscillations which occur along the direction of travel

what happens to particles in a longitudinal wave?

particles come close together and then pushed apart

what is it called when particles are close together in a longitudinal wave?

a compression

what is it called when particles are apart in a longitudinal wave?

rarefaction

what is another name for longitudinal waves?

pressure waves

how do transverse waves occur?

when the oscillation is perpendicular to the direction the waves travel

what are some examples of transverse waves

water waves/electromagnetic waves

where can electromagnetic waves travel through?

a vacuum

what can waves moving up and down be described as

undulations

how much faster is light than sound

about 1 million times faster

how fast does light travel?

at 300,000,000 m/s

how fast does sound travel in the air

340 m/s

what is sound caused by

vibrations in the air

describe the process of vibration in the air (for sound)

Air particles vibrate and collide with other air particles which then causes them to vibrate

what is the amplitude of a sound

how loud it is

how is amplitude measured in sound?

from the middle of the wave to the crest or trough of the wave

what is the amplitude of a soundwave measured in?

decibels

what are echoes examples of?

sound waves being reflected

when watching a cricket match, why does the sound of the bat hitting the ball arrive at your ears after you see it happen?

The speed of light is faster than the speed of sound. And so, the light waves reach your eyes before the sound waves reach your ears

what type of waves are sound waves

longitudinal

how is sound produced?

by the vibration of particles in a medium

what is a medium

the substance the wave travels through

how does sound travel?

in a series of compressions (where the medium is squashed together) and rarefactions (where the medium is stretched apart).

compressions

where the medium is squashed together

rarefactions

when the medium is stretched apart

why does photographic paper take a long time to form an image?

Because only a small amount of light enters through the pinhole, so it takes longer for enough light energy (photons) to build up and cause the chemical reaction in the silver halide crystals that forms the image.

why is the image in a pinhole camera blurred if the pin-hole is large?

because light from all directions from the object spreads out and overlaps on the screen

why is the image brighter with a large pinhole

because there is a higher concentration of light going through the hole

why would you have to cover the back of a pinhole camera with black paper?

so that the light will not reflect and hit other parts of the image

what are some examples of mirrors?

plane mirror/rearview mirror/telescope/side mirrors/oral mirrors

what should you do to the pinhole camera if you wanted a nice large clear image

make one small hole and bring it closer to the light source

why would the image formed by the pinhole camera be inverted?

Because light travels in straight lines and rays from the object cross over through the hole, causing it to be inverted

what do all waves do?

transfer energy from one place to another

time period

the time taken for one complete wave to pass by

frequency

the number of waves, cycles, or vibrations that pass a fixed point in a set amount of time, typically one second

how does something have a high frequency?

when the/a time period is shorter

what is the difference between the time period and frequency?

The time period is the time it takes to complete one full wave (measured in seconds), while frequency is the number of waves that occur per second (measured in Hertz)

peak

the highest point of a transverse wave

trough

the lowest point of a transverse wave

specular reflections

the type of reflection caused by smooth, shiny surfaces

Angle of incident ray

The light ray travelling towards the mirror or surface

Angle of incidence

the angle between the normal and incident ray.

Angle of reflection

angle between the normal and reflected ray

normal

A line at 90° to the reflecting surface, from which all angles are measured - usually represented by a dashed line.

reflected ray

The light ray travelling away from the mirror or surface.

what is the relationship between the angle of incidence and the angle of reflection?

they are equal

refraction

when light bends as it crosses a boundary

angle of refraction

the angle formed between the refracted ray of light and the normal line

where can you see information of a wave on?

an oscilloscope

how does an oscilloscope display information of a wave?

on a screen

superposition

the fact that waves can be added together, or cancel each other out

what would happen if waves superposed by adding together?

they will get bigger and increase amplitude

how would waves cancel each other out?

If, when they combine, one’s wave crest meets the other wave’s trough

what is the equation for wave speed

wave speed = frequency * wavelength

what is wave speed measured in?

m/s

what is wave length measured in?

metres

what is sound caused by?

vibrations in the air

How is sound produced?

when air particles vibrate and collide with other air particles, which then causes them to vibrate

what is the amplitude of sound

how loud it is

what does the decibel scale go up to

0 to 180

what is the maximum value on the decibel scale

280dB

what is the amplitude measured in for sound

decibels

what does amplitudes decide?

the volume of a sound wave

because sound is a wave, it can be…

absorbed/refracted/transmitted/reflected

transmition

the process in which light waves travel through a material, substance, or medium

what is an echo an example of?

reflected sound

how do sound waves travel through solids?

by causing vibrations in the solid

what are sound waves produced by?

the vibrations of particles in a medium

how does sound travel?

In a series of compressions and rarefactions

what can we use a microphone for?

to convert sound waves to electric signals that can be seen on an oscilloscope

How does a microphone and oscilloscope work together to show sound?

When sound waves hit the diaphragm inside a microphone, they cause it to move. This movement is converted into a matching electrical signal. The Oscilloscope plots the signals over time to form the images.

what may you be able to record by looking at an oscilloscope?

the wave’s amplitude, wavelength, frequency

how are loudspeakers formed

Electric current flows inside loudspeakers. This creates an electromagnet. The electromagnet attracts the speaker cone and moves it forwards and backwards towards a permanent magnet.This movement creates the sound. If you change the current, it will change the frequency of the cone and so the sound created will change

how do microphones work?

Sound waves hit the ‘diaphragm’ of the microphone.The diaphragm then moves backwards and forwards. This is attached to a coil and magnet, which produces a magnetic field.The movement of the diaphragm through the magnetic field generates an electric current. To increase the size of the current, you can use an amplifier

what happens to the frequency if the pitch increases

it increases

what does an oscilloscope do?;

shows a sound wave on a screen

what is a medium in reference to sound?

solids, liquids or gases that sound can travel through

how does sound travel?

at different speeds through different mediums

why does sound travel?

because of vibrating air molecules

why can’t sound travel through space

because sound travels because of vibrating air molecules and there is no air in space

where does sound travel the fastest?

through solids

why does sound travel fastest through solids

because the molecules are close together- allowing the vibrations to pass more quicker

how fast can sound travel in some solids?

5000m/s

how fast can sound travel in a liquid

up to 1500m/s

why does sound travel faster in water than air?

because water is denser than air- allowing sound waves to travel quickly

why can humans hear higher frequencies of sound underwater

because sound bypasses the outer and middle ear , going straight to the inner ear, avoiding the natural filter that blocks high frequencies

what is frequency to sound

it is the pitch of sound

the visible ear on the outside

pinna/outer ear

the tube leading inward the ear

ear canal

eardrum

a thin piece of skin that vibrates when sound hits it

in the middle ear at the end of the ear canal

eardrum

what are the 3 bones connected to the eardrum called?

hammer, anvil, stirrup