Conservation Of Energy Flashcards
What is an energy store?
Energy that an object can have
What is an energy transfer?
Energy that only exists when energy is being moved
What are the 6 energy stores?
Gravitational Potential
Elastic potential
Thermal
Kinetic
Chemical
Nuclear
What are the 5 energy transfers?
Work done
—> by forces
—> against electrical resistance
By radiation
—> sound
—> light
—> heating
What happens to wasted energy?
Ends up dissipated into the environment and as a thermal store (air gets slightly warmer)
What is the principle of energy conservation?
Energy cannot be created or destroyed, only transferred or stored
What is the efficiency equation?
Useful energy out
—————————
Total energy in
State an example of energy transfers happening:
- An object moving up a slope
Store= kinetic—> transfer= work done—> store= GPE - Bringing water to the boil
Store= n/a —> transfer= heating, electrical—> store= thermal - Car braking
Store= kinetic—> transfer = work done against friction—> store= thermal
State the equation for GPE:
GPE= Mass X Gravity X Height
State the equation for Kinetic energy:
KE = 1/2 X Mass X Velocity squared
What does efficiency mean?
The proportion of useful energy coming out compared to the energy put in
What is the unit for GPE/Kinetic energy?
J (joules)
What are some ways to keep a house warm?
Cavity walls
Loft insulation
Double glazed windows
Thicker walls
Carpets
What does a good insulator do?
Stops conduction, convection and IR radiation
What is thermal conductivity?
How easily a certain material loses its heat energy
High thermal conductivity=
Material will cool quickly
What is an insulator?
A material that keeps its heat
What is conduction?
Conduction is how thermal energy travels through solids. In a solid, the particles are tightly packed together in fixed positions. The particles are close together, vibrating in fixed positions. As the solid is heated, thermal energy is transferred into kinetic energy in the particles.
What is radiation?
Radiation involves transfer of heat via infra red waves, unlike thermal conduction and convection which need the vibration or movement of particles. This means radiation can occur in a vacuum, where there are no particles of matter. The sun provides heat to the earth due to radiation.
What is convection?
Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy
Why is a vacuum good?
Prevents conduction and convection
Why is a rubber seal good?
Prevents conduction
See book to test on power stations
How does kinetic energy work?
Energy in a moving object
How does GPE work?
Energy from being high up in a gravitational field
How does sound energy work ?
Energy passed through pressure waves
How does light energy work ?
Energy detected by our eyes
How does thermal energy work?
Energy held in a hot object
How does heating work?
Energy moved by conduction, convection or IR radiation
How does chemical energy work?
Energy held in the bonds of different molecules
How does nuclear energy work?
Energy holding atoms together
How does Elastic potential energy work?
Energy in something stretched or compressed
How does electrical energy work?
Energy from the movement of electrons
State 4 points on the changing use of energy resources in the UK:
- Coal has decreased to virtually nothing, from being the main source of energy, as it releases CO2 and contributes to global warming
- Renewable energy has increased as they are renewable and better for the environment
- Gas is 1/3 of our energy resources
- Wind and solar is increasing as they are renewable and clean
provides cheap power with well-known technology, but produces CO2 (a greenhouse gas) as well other particulates that lead to poor air quality?
Coal
Is expensive is to build and has ecological impact, but is renewable and reliable?
Tidal
Hydroelectric
Is renewable and relatively cheap, but isn’t reliable and people don’t like the look of them on the whole?
Wind
Is not renewable, but is unlikely to run out any time soon; however, it has very bad PR and is incredibly expensive? It also does not release CO2, which is good…
Nuclear
Is renewable, can be put anywhere including on micro scale (ie not whole power stations), but is unreliable and takes up lots of space if you want a decent output?
Solar
Is of interest to the UK in terms of a connection to Iceland, but we can’t build them ourselves? Renewable, reliable…
Geothermal
Is widely used in the UK, as we have our own fuel source, and also has a quick start-up time so we can get them online when everyone turns their kettles on, BUT are non-renewable, getting more expensive?
Gas
Is renewable, and can be built to STORE ENERGY by using pumps when there’s not much demand…
Hydroelectric
Is renewable, but very expensive, and requires very specific locations, but is reliable too…
Tidal
Is renewable, and is CARBON NEUTRAL, but does release CO2, and fuel supply is a problem if you’re thinking of scaling up?
Biomass
State 2 ways that coal is harmful to the environment:
- Release CO2 —> global warming
- Creates smog—> Respiratory problems
State what happens to the wasted energy:
Dissipated to the surroundings
In what way does the thickness of a material affect how good an insulator it is?
Air gets trapped
Are fossil fuels renewable ?
No
Are nuclear power stations renewable?
No
Are biomass power stations renewable?
Yes
Are wind power stations renewable?
Yes
Are wave power stations renewable?
Yes
Are tidal power stations renewable?
Yes
Are hydroelectric power stations renewable?
Yes
Are geothermal power stations renewable?
Yes
Are solar power stations renewable?
Yes
