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
