Year 8 Science, Physics

What is energy?

Energy is the capacity to cause change.

What is work?

Work is the process of using force to create change.

What is kinetic energy?

Kinetic energy is energy that involves the movement of particles.

What are examples of kinetic energy?

Heat, sound, light, and electrical energy.

What is potential energy?

Potential energy is energy that is stored and could be released.

What are examples of potential energy?

Gravitational, chemical, strain, and nuclear energy.

What is the difference between energy transfer and energy transformation?

Energy transfer involves the movement of one form of energy, while energy transformation involves energy changing from one form to another.

What is the Law of Conservation of Energy?

The law states that energy cannot be created or destroyed; the amount of energy before a conversion is equal to the amount after.

What is heat?

Heat is a measure of the total kinetic energy of all the vibrating particles in a substance.

How is heat related to temperature?

Temperature gives the average kinetic energy of vibrating particles.

What is conduction?

Conduction occurs when objects in contact share energy through the vibration of their particles.

What is convection?

Convection occurs in fluids when hot and cold particles mix due to differences in density.

What is radiation?

Radiation occurs when light is absorbed by particles, making them vibrate faster.

What is sound energy?

Sound energy is produced by vibrations that travel through matter in waves.

How is sound energy perceived by humans?

Sound waves enter the ear, causing the eardrum to vibrate, which is converted into an electrical signal interpreted as sound.

What is light energy?

Light energy is a form of energy that travels as electromagnetic waves.

How is light energy perceived by humans?

Visible light enters the eye, where the lens focuses it on the retina, converting it into an electrical signal interpreted as vision.

What is energy efficiency?

Energy efficiency is a measure of the useful output energy compared to the input energy of a system.

How is energy efficiency calculated?

Energy Efficiency (%) = (Useful Energy Output / Energy Input) × 100.

An example of Energy Transformation

A light bulb changes electrical energy into light energy and heat energy.

An Example of Conduction

holding a warm mug. The heat moves from the mug into your hand by direct contact.

An example of convection

pot of soup warming on the stove. As the soup at the bottom heats up, it rises while the cooler, denser soup sinks. That movement is convection, carrying heat around through the liquid.

An example of Radiation

the sun warming your skin through space with no contact needed.