1. Energy Flashcards
What is the law of conservation of energy?
Energy is never used up, it is just transferred between different energy stores and objects. It can be transferred, stored or dissipated but can never be created or destroyed.
What are the 8 energy stores?
- thermal
- kinetic
- gravitational potential
- elastic potential
- chemical
- magnetic
- electrostatic
- nuclear
What are the 4 different ways energy can be transferred?
- mechanically (a force doing work)
- electrically (moving charges)
- heating
- radiation (by light or sound)
What is a system?
A word for a single object or group or objects.
What is a closed system?
A system where neither matter nor energy can leave. The net changer in the total energy of a closed system is always 0.
How can energy be transferred by heating? (Example of kettle)
Energy is transferred electrically to the water which is the thermal energy store and causes the temp to rise.
What is work done?
Another way of saying energy transferred.
How can energy be transferred by doing work? (Example of a ball thrown)
As a person throws a ball upwards, work is done. This causes an energy transfer from the chemical energy store of the person to the kinetic energy store of the ball and arm.
How can falling objects transfer energy? (Example of a ball with no air resistance)
The ball is accelerated by gravity so the gravitational force does work. As it falls, the gravitational potential energy store’s energy is transferred into kinetic energy.
KE = 1/2 x m x v2 (what are the units?)
Ke= joules
Mass= kg
Speed= m/s
GPE= mgh (what are the units)
GPE= joules
Mass= kg
Gravitational field strength= N/kg (usually 9.8)
Height= m
EPE= 1/2 x k x e2 (what are the units?)
EPE= joules
Spring constant= N/m
Extension= m
Power = energy transferred/ time (what are the units?)
Power= watts
Energy transferred= joules
Time= s
What does lubrication do?
Reduces frictional forces that can save energy.
What does insulation do?
Reduces thermal energy that is lost.
How can you insulate a home?
- have thick walls made from a material with low thermal conductivity to reduce rate of energy transfer
- use thermal insulation such as
- cavity walls (gap to reduce conduction)
- loft insulation (insulator)
- double glazed windows (gap to reduce conduction)
- draught excluders (reducers convection)
What happens to all wasted/ dissipated energy?
It is eventually transferred to thermal energy stores
What are non- renewable energy resources?
Energy resources that will run out one day.
What are some examples of non- renewable energy stores?
- coal
- oil
- natural gas
What 3 things do coal, oil and natural gas have in common?
- they will all run out one day
- they all do damage to the environment
- they are reliable
What are renewable energy resources?
Energy resources that will never run out.
What are 7 examples of renewable energy resources?
- solar energy
- wind
- water waves
- hydro electricity
- bio fuel
- tides
- geothermal
What do all renewable energy resources have in common?
- they will never run out
- most of them do damage to the environment but in less harmful ways to the environment
- they don’t provide much energy and some are unreliable
What are the advantages of wind turbines?
- there’s no pollution
- no fuel costs and minimal running costs
- no permanent landscape damage
What are the disadvantages of wind turbines?
- they spoil the view (need 1500 to replace one coal fired power station)
- they can be very noisy
- stop when the wind stops and it is impossible to increase supply in strong winds
- high initial costs
What are the advantages of solar cells?
- best for calculator and watch batteries
- often used in remote places
- no pollution
- energy is free and running costs are super low
What are the disadvantages of solar cells?
- lots of energy to manufacture
- reliable only in daytime
- can’t increase power output when needed
- high initial costs
- small scale
What are the advantages of geothermal power?
- free and reliable
- can be used to generate electricity or heat buildings directly
What are the disadvantages of geothermal power?
- only possible in volcanic areas with hot rocks at the surface
- high cost for the amount of energy
- less locations
What are the advantages of hydro electric power?
- no pollution
- less human disadvantages
- immediate response
- high reliability
- no fuel costs and minimal running costs
What are the disadvantages of hydro electric power?
- usually requires flooding of a valley by building a big dam
- huge impact on environment (flooding, habitat loss, unsightly views)
- high initial costs
- works on only a small scale
- works only in remote areas
What are the advantages of wave power?
- no pollution
- no fuel costs and minimal running costs
- useful on small islands
What are the disadvantages of wave power?
- need lots of small wave powered turbines around the coast
- disturbs seabed and habitats
- spoils view
- hazard to boats
- fairly unreliable
- high initial costs
- not useful on large scale
What are the advantages of tidal barrages?
- no pollution
- reliable
- no fuel costs and minimal running costs
- can generate a significant amount of energy
What are the disadvantages of tidal barrages?
- prevents access by boats
- spoils view
- alters habitat
- height of tides can change energy produced
- high initial costs
- only some suitable estuaries
What are the advantages of bio fuels?
- they are carbon neutral mostly
- fairly reliable (crops take short time to grow)
What are the disadvantages of bio fuels?
- cannot respond to immediate energy demands
- cost is very high
- not enough space or water for growing crops to eat
- large areas of forest have been cleared resulting in loss of habitats
- forests have been cleared using slash and burn method
How does wind power work?
Each turbine has a generator inside and the rotating blades turn the generator and produce electricity
How do solar cells work?
Solar cells generate electric currents directly from sunlight
How does geothermal power work?
Energy is taken from underground thermal energy stores
How does hydro electric power work?
It transfers energy from the kinetic store of falling water by creating dams
How does wave power work?
Turbines spin due to water flow and energy is sent to a generator
How do tidal barrages work?
Big dams are built with turbines in them. As the tide comes in it fills up the estuary and the tide is allowed out at a control speed. (Energy from kinetic energy)
How does bio fuel work?
Either plant products or animal dung are burnt to produce thermal energy.
What environmental problems are created by non renewable energy sources?
- greenhouse effect
- sulfur dioxide released from burning coal and oil which causes acid rain
- spoils views
- oil spillages kill mammals and birds
- nuclear waste is dangerous and difficult to dispose of
- nitrogen oxide can cause acid rain and smog
