Study notes

Energy Forms & Conversion

Energy is the ability to do work, and it can be converted from one form to another while being conserved.

Learn it step by step

Forms of Energy

Energy exists in many forms around us, such as kinetic, potential, light, heat, sound, and electrical energy. Each form helps us perform different daily tasks or causes changes in our surroundings.

Kinetic and Potential Energy

Kinetic energy is the energy possessed by a moving object due to its motion. Potential energy is stored energy, which includes gravitational potential energy, elastic potential energy, and chemical potential energy.

Energy Conversion

Energy cannot be created or destroyed, but it can be converted from one form to another. For example, when a torch is turned on, chemical potential energy in the batteries is converted into electrical energy, then into light and heat energy.

Energy from the Sun

The Sun is the main source of energy for Earth. It provides light and heat energy, which plants use during photosynthesis to make food, storing it as chemical potential energy.

Food as Stored Energy

Food contains chemical potential energy. When living things consume food, their bodies convert this stored energy into kinetic energy for movement and heat energy to keep their bodies warm.

Worked examples

A rubber band is stretched and released to shoot across the room. State the energy changes from the moment it is stretched to when it is flying through the air.

Identify the starting state: The stretched rubber band possesses elastic potential energy.
Identify the moving state: When released, the rubber band moves through the air, possessing kinetic energy.
State the complete energy conversion: Elastic potential energy is converted to kinetic energy.

Describe the energy conversion that takes place when a toy car rolls down a slope from rest.

Identify the starting position at the top of the slope: The car has gravitational potential energy.
Identify the action as it rolls down: The car loses height and gains speed, meaning gravitational potential energy decreases while kinetic energy increases.
State the conversion: Gravitational potential energy is converted into kinetic energy and a small amount of heat energy due to friction.

Explain how a green plant obtains its energy and stores it for future use.

Identify the source: The plant traps light energy from the Sun.
Describe the process: The plant uses this light energy, along with water and carbon dioxide, to make food during photosynthesis.
State the final form: The food produced stores this energy as chemical potential energy.

Mind map

Practise this topic →