Section 4 - Energy Resources and Energy Transfer Flashcards
9 Types of Energy
1) Electrical, 2) Light, 3) Sound, 4) Kinetic, 5) Nuclear, 6) Thermal, 7) GPE, 8) Elastic Potential, 9) Chemical
Stored Energies
GPE, Elastic Potential, and Chemical energies are stored energies as they are not doing anything, but waiting for something to happen to them
Law of the Conservation of Energy
Energy can be neither created nor destroyed, only transferred from one form to another
Energy is only useful when…
it can be transferred from one form to another
Efficiency
useful energy output/total energy input
Energy Transfers
Electrical devices convert energy into sound, light, heat, etc
Batteries convert chemical to electrical
GPE and Elastic potential always get converted to Kinetic Energy first
Electricity generation always involves converting one form of energy into electrical energy
Transferring Heat Energy
Heat can be transferred by: radiation, conduction, convection
Thermal (infrared) radiation is…
the transfer of heat energy by electromagnetic waves
Conduction
- involves particles
- main form of heat transfer in solids
Emission of thermal radiation occurs in…
solids, liquids and gases
Effect of temperature difference on heat transfer
The greater the temperature difference, the greater the rate of heat transfer
Conduction of heat
Conduction of heat is the process where vibrating articles pass on their extra kinetic energy to neighbouring particles - mainly occurs in solids
Convection occurs…
when the more energetic particles move from the hotter region to the cooler region: taking their heat energy with them - only occurs in fluids
Convection currents
- Convection currents are all about change in density
- Hot fluid is less dense than cool fluid
- Therefore it rises, and the cooler fluid flows to replace it
Work is done when…
a force moves an object: transferring energy
Formula for work done
Wd(J) = F(N)*d(m)
Formula for power
P(W) = Wd(J) / t(s)
Formula for kinetic energy
Ke(J) = ½ * m(kg) * v²(m/s)
Formula for G.P.E
G.P.E. = m(kg) * g(m/s) * h(m)
Non-renewable resources
Coal, oil, natural gas, nuclear fuels(uranium and plutonium)
How power stations work
- Fuel is burnt
- Heat is used to create steam
- Steam turns a turbine
- Turbine turns a generator
Advantages of burning fossil fuels
- Releases lots of energy
- Relatively cheap
- Doesn’t rely on the weather(reliable)
Disadvantages of burning fossil fuels
- Release carbon dioxide(global warming)
- Burning coal and oil releases sulphur dioxide, which can cause acid rain
- Non-renewable
Nuclear power stations
do the same as fossil fuel power stations, but they produce the heat through nuclear fission
Disadvantages of nuclear power stations
- Expensive to build and maintain
- Processing the uranium before use causes pollution
- Risk of a leak of radioactive material
- Expensive to decommission
- Produces radioactive waste
Advantages of nuclear power stations
- Doesn’t produce any greenhouse gases
- Plenty of uranium to be mined
Advantages of wind turbines
- Cheap to run(wind is free)
- Tough and reliable
- Doesn’t produce any pollution
- Reliable
Disadvantages of wind turbines
- Spoil the view
- Doesn’t produce as much power as a coal station(1 coal station worth 1500 wind turbines)
- Takes up a lot of space
- Expensive to set up a wind farm
- Unreliable
Advantages of geothermal energy
- Renewable energy
- No real environmental issues
Disadvantages of geothermal energy
- Expensive to construct(needs extensive drilling)
- Often doesn’t produce enough power to justify construction
How geothermal generators work
- Water is pumped down(through pipes) to areas of hot rocks under the ground
- The heat is often created by the slow decay of radioactive elements
- Water forced back up due to pressure, and turns a turbine
- Turbine turns a generator
Solar cells(photocells)
- Turn light energy directly into electrical energy
- Generate D.C.
Advantages and disadvantages of photocells
- Renewable energy source
- No pollution
- Practically no running costs
- Expensive to set up
- Often not practical to connect to the national grid
- Unreliable(cloudy/nighttime = no power)
Solar heating systems(solar panels)
- Simpler than solar cells
- Capture heat
- Basically black water pipes in a glass box
- Cost money to set up, but renewable practically no running cost
Wave power
- Utilises the up and down motion of waves to drive a generator
- Transfers the waves kinetic energy into electrical energy
- No pollution
- Renewable
- Fairly unreliable(dependant on wind)
- High initial costs
- Minimal running costs
- Unlikely to provide power on a large scale
Tidal barrages
- Big dams built across river estuaries
- Contain turbines
- When tide comes in, the estuary is filled up to a height of several metres
- The water can then be allowed out through the turbines in a controlled manner
- Renewable
- No pollution
- Prevents free access by boats
- Spoils the view
- Alters the habitat of the wildlife
- Pretty reliable(although variable)
- Moderately high initial costs
- Minimal running costs
Hydroelectricity
- Flooding a valley by building a big dam
- Renewable
- No pollution
- Big environmental impact(loss of habitat + rotting vegetation produces methane)
- Reliable(except droughts)
- High initial costs
- Unsightly
- Can be used for an immediate response
