Energy Transfers

• What happens when energy is transferred to an object?

  The energy would be stored in one of the object's energy stores
• Name all the 8 energy stores

  Kinetic, Thermal, Chemical, GPE, Elastic, Electrostatic, Magnetic, Nuclear
• What is a system?

  An object or group of objects
• What is a closed system?

  Where neither matter nor energy can enter or leave
• Energy can be transferred between stores in 4 main ways

  Mechanically, Electrically, Heating, radiation
• Mechanically


  an object moving due to a force acting on it
• Electrically


  a charge moving through a potential difference
• Heating


  energy transferred from a hotter object to a colder object
• Radiation


  energy transferred by light/sound waves
• What is another way of saying energy transfered

  Work done
• Conservation of mass principle


  Energy can be transferred usefully, stored, or dissipated but can never be created or destroyed
• What happens when energy is transferred between stores


  Not all of the energy is transferred usefully to the store you want it to go, some energy is dissipated
• What does the conservation of energy principle explain


  Why the total energy in a closed system is always the same . No energy can enter or leave s closed system and since energy cannot be created nor destroyed the total energy is always the same
• What is kinetic energy

  Anything moving
• Thermal energy


  Heat
• Chemical energy


  Releases energy by chemical reaction
• GPE 


  anything that has mass and is inside a gravitational field
• Elastic


  Stretched or compressed
• Electrostatic


  anything with electric charge
• Magnetic


  2 magnets that attract or repel each other
• Nuclear


  atomic nuclei has energy in the store that can be release in nuclear reactions
• What equipment's do you need to investigate heat capacity


  Power supply, heater, thermometer, block of material, insulation, ammeter
• What is power?


  Power is the rate of energy transfer or the rate of doing work
• What is he measurement of power?

  Watts (W)
• An equation to calculate power


  P= E/t or P = W/t
• What does E and T and F stand for?


  E = energy transferred, T = time W = Work done
• What is conduction?


  Conduction is the process by which vibrating particles transfer energy to neighbouring particles
• What state do conductions mainly occur?

  Solids
• What is thermal conductivity?

  Is a meausre of how quickly energy is transferred through a material in this way
• The higher the conductivity of a material the ________

  Higher the rate of energy transfer by conduction across material
• What is convection?


  Convection is where energetic particles move away from hotter to cooler regions
• What is unwanted energy?

  Wasted energy
• How can you reduce the amount of energy lost in a building?

  Thermal insulators
• What is lubrication?


  Reducing friction
• What is efficiency?


  The less energy that is 'wasted' the more efficient the device is said to be
• Formula for efficiency 


  efficiency = useful output energy transfer

  total input energy transfer
• How can you improve efficiency?

  By insulating objects lubricating them or making them more streamlined
• Another formula for efficiency 


  efficiency = useful power output divide total power input
• Cavity walls and cavity wall insulation


  Walls made up of an inner and an outer wall with an air gap in the middle, the air gap reduced the amount of energy transferred by conduction through the walls because air is an insulator.
• Loft insulation


  Fiberglass is an insulating material made up of thin strands of glass that trap pockets of air.