Energy Transfer and Efficiency
Types of EnergyThere are 10 types of energy which can be remembered using the phrase: Most Kids Hate Learning GCSE Energy Names
Magnetic Kinetic - movement energy Heat - kinetic energy in molecules, when things are hot Light Gravitational Potential- energy you have if you are high up Chemical - stored energy in things like batteries and food Sound - molecules vibrating in waves Electrical - electrons moving in a circuit Elastic Potential - energy gained by stretching things Nuclear |
Law of Conservation of EnergyEnergy cannot be created or destroyed; it is just transfered from one type to another.
eg. a Light bulb turns Electrical Energy into Light and Heat. |
Sankey Diagrams
We can represent energy transfer using a Sankey Diagram. Here are the rules for drawing them:
1) All arrows must be labelled with their energy type, efficiency and number of Joules 2) All useful energy arrows are horizontal 3) All wasted energy arrows are vertical 4) The arrow width is proportional to its percentage of energy. |
Efficiency can be calculated using the formula:
On the left is a Sankey diagram for a light bulb. It produces 10J of useful light energy and 90J of wasted heat energy. Can you calculate the efficiencies? |
You may find the following Phet simulation useful: