1 - energy Flashcards
8 energy stores
- thermal
- kinetic
- gravitational potential
- elastic potential
- chemical
- magnetic
- electrostatic
- nuclear
how can energy be transferred
mechanically
electrically
by heating
by radiation
whats a closed system
no matter or energy can enter or leave
whats specific heat capacity
amount of energy needed to raise the temp of 1kg of a substance by 1 degrees
conservation of energy principle
energy can be transferred usefully, stored or dissipated but can never be created or destroyed
example of dissipated energy
phones: useful - chemical /// wasted - thermal
what is power
rate of energy tranfer/ doing work
definition of conduction
vibrating particles transfer energy to neighbouring particles
about conduction
- when particles heated they vibrate in solids and cause collisions
- this tranfers energy ebtween the particles kinteic energy stores
- goes from one end of an object to the other end and then out into the surroundings
definition of convection
energetic particles move away from hotter to cooler regions
where does convention occur
- happens in liquids and gasses
radiator convention currents
Air near the radiator is heated, which causes it to become less dense. Therefore this warm, less dense air rises up the room, and the cold, denser air above it sinks down. The cold air can now be heated by the radiator.
lubricants
- A moving object normally has at least one frictional force acting against it. This causes some energy to be dissipated.
- LUBRICANTS reduce friction between objects’ surfaces when they move past each other
thermal insulation in the home
- CAVITY WALLS - inner and outer wall with an air gap in middle - reduces conduction
air gap filled with foam - reduces convection - loft insulation - reduces convection currents
- double glazing windows - air gap reduces conduction
non renewable energy resources
fossil fuels
1. coal
2. oil
3. natural gas
renewable energy resources
- solar
- wind
- water waves
- hydro electrity
- bio fuels
- tidal
- geothermal
wind power - what cons pros
- wind turbine with a generator produce electricity
- spoil view/ need lots to make not much power / noisy/ dependent on wind
- minimal running costs/non polluting / no permanent damage to landscape
solar cells - what cons pros
- generate electrical current from sunlight - charge calculators/ watches
- reliable on sun daytime/ cant increase power output when high demand/high initial costs
- no pollution/ minimal maintenance costs
geothermal power - what cons pros
- volcanic areas
- free/reliable/doesnt damage environment
- not many suitable locations
hydro-electric power - what cons pros
- flooding from a dam and water allowed out through turbines
- flood v bad/ high upfront cost
- provide immediate response/ reliable except for drought/ minimal running costs
waves power - what cons pros
- small wave powered turbine near the coast
- disturbs seabed habitats/ spoils the view / hazard to boats/ high upfront costs
- not polluting/ minimal running coasts
tidal barrages - what cons pros
- big dams across estuaries
- boats cant get through/ spoils view/ alters wildlife / high upfront costs
- no pollution/ reliable twice a day without fail due to being controlled by the gravitational pull between the sun and the moon/ minimal running costs
what are bio fuels
- made from plant products or animal dung / can be burnt to produce electricity or run cars in the same way as fossil fuels
- cant respond to immediate energy demands/ deforestation to make space to grow crops
- reliable
pros and cons of fossil fuels and nuclear energy
- reliable and can meet current demand / cost effective
- slowly running out
environmental problems of fossil fuels and nuclear energy
- greenhouse effect - global warming
- burning coal - sulphur dioxide - acid rain
- oil spillages - damage habitats
- nuclear waste - v dangerous and difficult to dispose of
- nuclear risk of disaster
