Energy in a nutshell

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  • Created on: 14-04-13 13:30
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IGCSE Energy in a nutshell
1. Types of energy are: electrical, sound, kinetic, chemical, nuclear and potential (elastic and
2. Energy is conserved (not created or destroyed)but changed to other form s
3. Efficiency = useful energy output/ total energy input
4. Dissipation of energy is when it is spread thinly to billions of particles in the surrounding s
5. Describe a variety of everyday and scientific devices and situations, explaining the fate of
the input energy including their representation by flow diagrams
6. Thermal energy transfer can take place by conduction, convection and radiation
7. Methods of home insulation include double glazing, cavity wall insulation. These prevent
heat loss from the home by conduction or convection.
8. A foam insulator is better than a continuous air space since very little convection can take
place in small air pockets so convection as well as conduction losses are very small. This
explains why cavity wall insulation is effective.
9. Energy is transferred when work is done. Work done = force × distance moved by the force
-unit Joule
10. Kinetic energy = ½ × m v2
11. Gravitational potential energy = mgh
12. Power = rate of doing work. Power = Work done/ time taken -unit Watt
13. Non-renewables (oil, coal, gas)are being used at a faster than they are being produced so
will run out unless practice changes or more are discovered. They also contribute to global
warming by releasing carbon dioxide and to acid rain by releasing sulphur dioxide. They
contain a large amount of chemical energy per unit mass.
14. Renewables (wind, waves, hydroelectric, tidal, biomass, geothermal) are constantly
replenished with energy from the sun so will continue for as long as the sun shines. They
tend to be less polluting though may destroy habitats eg when valleys are flooded. They
tend to contain less energy per unit mass than fossil fuels so produce on a much smaller
scale .
15. Block diagram showing stages in a power station, particularly the turbine and generator
showing energy transfer from
a. chemical to thermal to kinetic to electric for fossil fuel power stations
b. gravitational potential to kinetic to electric for hydroelectric power stations
c. kinetic to electric for wind power
d. nuclear to thermal to kinetic to electric for nuclear power stations


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