Transferring energy

• Mechanical Energy to Electrical Energy


  Converted through generators like wind turbines or power plants
• Electrical Energy to Thermal Energy


  Converted through electromagnets like electric stove coils
• Chemical Energy to Electrical Energy


  Converted through batteries
• Transferring energy =

  -mechanical work

  -electrical work

  -heating

  -waves
• Mechanical work - transferred by force

  eg. Object falls = gravitational -> kinetic
• Electrical work - electrical current transfer

  e.g torch
• Heating - transfer energy to its internal store

  increase temperature
• Waves - transfer energy

  eg. Light waves
• Work done - push the same force for a longer distance / push a larger force for the same distance
• Work done - Force x distance
• Change in Thermal energy (J)= Mass (kg) x Specific Heat Capacity(J/kg *C) x Temperature Change (*C) △E = m x c x △O
• △E (J) = m (kg) x c (J/kg *C) x △O (*C)
• Electrical work - work done when a current flows

  energy = potential difference (V) x current (I) x time (t)

  E (J) = V I t
• Conduction - when a solid is heated, particles Vibrate and collide more, energy is transferred
• Power - rate of transfer of energy, amount of work done in a given time
• Power (W) = energy transferred (J) / time (s)

  P=E/t
• Power (W)= work done (J) / time (t)

  P = W/t
• convection - liquid/gas heated, particles move faster. Meaning that the liquid/gas becomes less dense. Denser region rises above cooler region
• Wasted energy

  -in unwanted stores

  -dissipate(spread out) to anything nearby

  eg. Noise(cars, kettles)

  heat (wires, cars, friction)
• Reduce wasted energy :

  -lubrication

  -thermal insulators

  -walls in homes
• Lubrication - frictional forces (liquid )
• Thermal insulator :

  -loft insulator

  -double glazing

  -wall insulation

  -carpets
• Walls in home :

  -thicker walls

  -walls made from low thermal conductivity material