Physics

What is energy transfer?

The movement of energy from one object or place to another without necessarily changing its form.

What is energy transformation?

The conversion of energy from one form into another.

What is the Law of Conservation of Energy?

Energy cannot be created or destroyed; it can only be converted from one form to another.

What is the difference between heat and temperature?

Heat or thermal energy depends on the total kinetic energy of particles while temperature depends on their average kinetic energy.

What is absolute zero?

Approximately -270°C where particles have almost stopped moving.

What are the three methods of heat transfer?

Conduction convection and radiation.

What is conduction?

Heat transfer that occurs when particles pass kinetic energy to neighbouring particles through collisions.

Why are metals good conductors of heat?

Their electrons are freer to move allowing them to transfer kinetic energy more easily.

What is an insulator?

A material that is a poor conductor of heat such as polystyrene foam wool and fibreglass.

What is convection?

Heat transfer through the actual movement of particles in liquids and gases.

What is radiation?

Heat transfer through electromagnetic radiation which does not require particles.

How does heat from the Sun reach Earth?

Through radiation mainly in the form of infrared radiation.

What is a transverse wave?

A wave where particles vibrate at right angles to the direction of energy transfer.

What are examples of transverse waves?

Ripples on a pond vibrations of a string light and S-waves in earthquakes.

What is a longitudinal wave?

A wave where particles vibrate forwards and backwards in the same direction as energy transfer.

What are examples of longitudinal waves?

Shock waves P-waves in earthquakes and sound waves.

What type of wave is sound?

A longitudinal wave.

What type of wave is light?

A transverse wave.

Where does sound travel fastest?

In solids then liquids and slowest in gases.

Why does sound travel fastest in solids?

Because their particles are closest together allowing vibrations to transfer more quickly.

What does the outer ear do?

The auricle collects sound waves and funnels them through the ear canal to the eardrum.

What are the three tiny bones in the middle ear?

The hammer anvil and stirrup.

What does the cochlea do?

Its hair cells respond to different sound frequencies and convert vibrations into electrical signals that travel to the brain.

What frequency range can humans normally hear?

20 Hz to 20000 Hz.

What is loudness measured in?

Decibels or dB.

What is an echo?

The reflection of a sound wave from a surface.

What is the order of the electromagnetic spectrum from lowest to highest energy?

Radio waves infrared visible light ultraviolet X-rays gamma rays.

What happens to frequency energy and wavelength as you move higher through the electromagnetic spectrum?

Frequency and energy increase while wavelength decreases.

What is refraction?

The bending of light when it passes into a different material because its speed changes.

What is the difference between convex and concave lenses?

Convex lenses converge light rays while concave lenses diverge light rays.