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Energy Transfer

Noadswood Science, 2012

+Energy & Electricity

To revise energy transfers and work out current and charge in an electric circuit

Monday, April 10, 2023

+Energy

What is energy?

What types of energy are there?

+Energy

Energy is the ability to ‘do some work’ - everything that happens needs energy (e.g. heating; cooking; lighting; movement of vehicles; and keeping us alive)!

Energy cannot be created or destroyed, only transferred from place to place in a variety of ways

+Types Of Energy

Electrical energy - a current in a circuit etc… Light energy - from the sun; a light bulb etc… Sound energy - from a loudspeaker; a drum etc… Kinetic (movement) energy - anything which moves! Nuclear energy - transferred during a nuclear reaction Thermal (heat) energy - transferred from hot objects to

colder ones Radiant heat (infra red) energy - transferred as

electromagnetic radiation by hot objects Gravitational potential energy - possessed by anything

with the ability to fall Elastic potential energy - stretched springs; elastic and

rubber bands etc… Chemical energy - possessed by food; fuels; batteries

etc…

+Energy Transfer

Different types of energy can be transferred from one type to another

Energy transfer diagrams show each type of energy, whether it is stored or not, and the processes taking place as it is transferred

+Energy Transfer

Different types of energy can be transferred from one type to another

Energy transfer diagrams show each type of energy, whether it is stored or not, and the processes taking place as it is transferred

+Sankey Diagrams

Sankey diagrams show the relative amounts of each type of energy

They summarise all the energy transfers taking place in a process – the thicker the line or arrow, the greater the amount of energy involved

Sankey diagram of a light bulb

+Wasted

Energy can be 'wasted' during energy transfers

Energy cannot be created or destroyed, only transferred from one form to another

Energy that is ‘wasted’ (e.g. heat energy from an electrical lamp) does not disappear – instead it is transferred to the surroundings, spreading out so much that it becomes difficult to do anything useful with

+Lamps - Ordinary

Ordinary electric lamps contain a thin metal filament that glows when electricity passes through it – however, most of the electrical energy is transferred as heat energy instead of light energy: -

+Lamps – Energy Saving

Modern energy-saving lamps work in a different way – they transfer a greater proportion of electrical energy as light energy: -