Edexcel GCSE 9-1 Physics : SP3 - Conservation of Energy

Paper 1 Specification: https://qualifications.pearson.com/content/dam/pdf/GCSE/Science/2016/Specification/GCSE_Physics_Spec.pdf

3.1 Recall and use the equation to calculate the change in gravitational PE when an object is raised above the ground

∆GPE = m× g ×∆h

3.2 Recall and use the equation to calculate the amounts of energy associated with a moving object:

KE = ½ mv ²

3.3 Draw and interpret diagrams to represent energy transfers

energy diagrams = shows energy transferred by forces from an object to another object

Sankey diagram = width of arrow represents amount of energy in joules

3.4 Explain what is meant by conservation of energy

• energy cannot be created or destroyed

• energy can only be transferred from one store to another

• total energy transferred by a system is the same as the energy put into the system (J)

3.5 Analyse the changes involved in the way energy is stored when a system changes, including:

a) an object projected upwards or up a slope

kinetic → gravitational

3.5 Analyse the changes involved in the way energy is stored when a system changes, including:

b) a moving object hitting an obstacle

kinetic → heat + sound

3.5 Analyse the changes involved in the way energy is stored when a system changes, including:

c) an object being accelerated by a constant force

chemical → kinetic

3.5 Analyse the changes involved in the way energy is stored when a system changes, including:

d) a vehicle slowing down

kinetic → heat

3.5 Analyse the changes involved in the way energy is stored when a system changes, including:

e) bringing water to a boil in an electric kettle

electrical → heat

3.6 Explain that where there are energy transfers in a closed system there is no net change to the total energy in that system

energy transfers in a closed system = no net change to the total energy in that system

3.7 Explain that mechanical processes become wasteful when they cause a rise in temperature so dissipating energy in heating the surroundings

mechanical processes become wasteful when temp increase so dissipating energy in heating the surroundings

3.8 Explain, using examples, how in all system changes energy is dissipated so that it is stored in less useful ways

Input energy transfers to light, sound, heat

3.9 Explain ways of reducing unwanted energy transfer including through lubrication, thermal insulation

lubrication: less friction so less heat is created

thermal insulation: less heat lost to surroundings

3.10 Describe the effects of the thickness and thermal conductivity of the walls of a building on its rate of cooling qualitatively

• thicker walls mean greater thermal insulation, so less heat is lost

• cavity walls reduce unwanted heat energy transfer as they fill cavities, prevent air flow and insulate

3.11 Recall and use the equation:

efficiency = useful energy transferred ÷ total energy supplied

efficiency = useful energy transferred ÷ total energy supplied

3.12 Explain how efficiency can be increased

• reduce waste output (via lubrication / insulation)

• recycling waste output and using it as input (absorbing heat energy dissipated and
  used to as input heat energy)

3.13 Describe the main energy sources available for use on Earth including:

fossil fuels

fossil fuels (non-renewable) = coal, oil, natural gas

oil (petrol and diesel) are used in most vehicles, aeroplanes and ships because they store a lot of energy and can be put in engines

natural gas burnt to heat homes or for cooking

3.13 Describe the main energy sources available for use on Earth including:

nuclear fuel

uranium, store a lot of energy in a small piece of material. useful for spacecraft

3.13 Describe the main energy sources available for use on Earth including:

bio-fuel

used in same ways as fossil fuels and made from animal wastes or plants

carbon neutral: when burnt, release the same amount of carbon dioxide that they took from the atmosphere during growth (however energy is also needed to grow and harvest the crops and to turn them into fuel, so not really carbon neutral)

3.13 Describe the main energy sources available for use on Earth including:

wind

wind turbines - generates electricity but needs the wind speed to not be too slow or too fast.

• a lot are needed to produce the same amount of energy as a fossil fuelled power station

• spoils landscape

3.13 Describe the main energy sources available for use on Earth including:

hydro-electricity

generated by falling water in places where water can be trapped in high reservoirs

available any time (as long as it does not dry up)

their powerstation can be started and stoped very quickly, unlike fossil fuel power stations

3.13 Describe the main energy sources available for use on Earth including:

tidal power

tidal power can generate electricity when turbines in a dam turn as the tides flow in and out.

• not available all the time but is available at predictable times.

• not many places in the UK that are suitable for dams (barrages)

• may affect birds and other wildlife that live or feed on tidal mudflats

3.13 Describe the main energy sources available for use on Earth including:

solar energy

solar cells convert solar energy directly into electrical energy

• can be used in power stations

• used to heat water for use in homes

• not available at all times

3.14 Explain patterns and trends in the use of energy resources

renewable energy sources are resources that will not run out, cause pollution or emit carbon dioxide. burning fossil fuels (non-renewable) releases carbon dioxide and other gases, contributing to climate change and pollution

countries are trying to cut down their use of fossil fuels as they want to reduce pollution and make supplies of the fuels last longer