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Smallest particle of matter

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2 or more atoms joined together

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A substance that cannot be separated into simpler substances, these substances are found in the periodic table.

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2 or more elements joined together to form chemical bonds.

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Made from two or more substances but are not bonded and their elements are not in a specific ratio.

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3 types of heat transfer
- Conduction
- Convection
- Radiation

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Long wavelength = low pitch
Short Wavelength = high pitch

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The change in direction in the ray of light when it hits a surface without passing through it.

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A wave vibrating in the direction of propagation.

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Converging Lenses: A lens that causes rays of light parallel to the axis to converge at the principal focus.Diverging Lenses: A lens that causes rays of light parallel to the axis to diverge from the principal focus.

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The number of compressions which pass a certain point in one second.

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The distance between two consecutive compressions.

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Angle of Incidence: The angle between an incident ray and the normal to the surface at the point where it meets a surface.
Angle of Reflection: The angle between a reflected ray and the normal to the surface at the point where it reflects from a surface

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Virtual Image: An image that cannot be formed on a screen. Formed when rays of light appear to be spreading out from a point.
Real Image: An image that can be formed on a screen.

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Incident Ray = A ray of light striking a surface
Reflected Ray = A ray of light that has been reflected after it has hit a surface.

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The bending of a ray of light on passing from one material from another.

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Heat Energy

Type of energy which moves from hotter objects to cooler objects

Temperature

Average amount of kinetic energy that a substance contains

Kinetic Particle Theory

Theory that all matter is made of moving particles

Phase change

When potential energy between particles either increases or decreases, but kinetic energy stays the same.

Joule

Units used to measure amount of heat energy

Kinetic Energy

Energy of movement

Potential Energy

Stored energy

Specific Heat Capacity

Amount of heat energy required to heat 1kg of a substance by 1 degree.

Specific Latent Heat

Amount of heat energy required to change state.

Absolute Zero

Temperature at which particles within matter stop moving, -273 degrees K

Conduction

Heat transfer in particles within a solid.

Convection

Heat transfer in fluids, where heated particles expand, become less dense and rise.

Radiation

Heat transfer through electromagnetic waves - particles not needed

Convection Current

Cycle where warmed particles in fluids expand, become less dense and rise, while cooler particles are more dense and sink.

Radiant Heat

Heat energy radiating off hot objects

Conductor

Material that conducts/transfers heat well.

Insulator

Material that does not conduct/transfer heat well.

Transverse Waves

Mechanical wave where particles move perpendicularly to the direction of energy movement.

Longitudinal Wave

Mechanical wave where particles move parallel to the direction of energy movement.

Compression

Area of high particle density in a longitudinal wave.

Rarefaction

Area of low particle density in a longitudinal wave.

Frequency

Number of waves which pass a given point in a given unit of time.

Amplitude

Height from mean position to the crest of a wave.

Wavelength

The distance from crest to crest in a wave (or like position to like position)

Pitch

How high or low a sound is - the higher the wave frequency, the higher the pitch of the sound.

Hertz

Standard unit for frequency - one wave cycle per second.

Crest

Maximum displacement of particles in a wave above the mean position.

Trough

Maximum displacement of particles in a wave below the mean position.

Mean position

Position of particles in a wave at rest.

Sound Waves

Longitudinal mechanical wave which transfers sound energy through particles.

Speed of sound

How fast sound travels - approximately 340m/s

Sonar

The transmission of high frequency sound pulses which hit objects under water that reflect some of the sound waves back to the source.

Ultrasound

a medical imaging technique that uses high frequency sound waves and their echoes.

Vacuum

Absence of matter/particles

Echolocation

Technique used by bats, whales and dolphins where they locate objects using high frequency sound waves and their echoes.

Echo

The reflection of sound waves

Sound intensity

Sound waves per unit area.

Decibel

Unit of measurement for intensity of sound

Cochlea

Snail shaped part of the inner ear containing fluid and hairs which converts mechanical energy into electrical energy (nerve impulses)

Ear Canal

Tunnel shaped part of outer ear which leads to the ear drum/tympanic membrane

Eardrum

AKA tympanic membrane, converts sound energy into mechanical energy

Auricle

AKA pinna, funnel shaped part of outer ear which funnels sound waves into the ear canal

Semi-circular canals

3 circular tubes containing fluid which allow the body to detect where it is in 3D space.

Auditory nerve

Nerve which carries nerve impulses from the cochlea to the brain.

Ossicles

The 3 bones of the middle ear, smallest bones in the body - incus, stapes and malleus.

Electromagnetic spectrum

Spectrum of energy waves which don't require matter to be transferred through - in order from largest to smallest wavelength.

Radio waves

Waves with relatively large wavelengths used for communication - cannot be seen by eyes.

Infra-Red Radiation

Waves with a wavelength just longer than visible light - used in thermal imaging - cannot be seen by eyes

Visible light

Waves with a wavelength which can be detected by the eye - light we can see

Ultraviolet radiation

Waves with a wavelength just shorter than visible light - cannot be seen by eyes, can cause sunburn.

X-Rays

Waves with a shorter wavelength than UV radiation, can be used for medical imaging. Cannot be seen by eyes

Gamma Rays

Waves with a very short wavelength - shorter than X-rays. Can be used for as a treatment for cancer. Cannot be seen by eyes.

Luminous

An object / material which produces its own light

Transparent

Material which allows all light to transfer through it.

Translucent

Material which allows some light to transfer through it but also absorbs some light.

Opaque

Material which absorbs all light, not allowing light to transfer through it.

Scattering

When light is reflected off an uneven surface spreading light in a variety of directions

Reflection

When a material reflects light back towards its source.

Plane Mirror

A flat mirror which reflects light

Convex

referring to a mirror or lens where the surface bulges outwards towards the light source.

Concave

referring to a mirror or lens where the surface curves inwards away from the light source.

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A wave in which the medium vibrates at right angles to the direction of its propagation.