Topic 1

• 8 types of energy


  • Thermal
  • Gravitational potential
  • Electrostatic
  • Magnetic
  • Chemical
  • Kinetic
  • Elastic potential
  • Nuclear
• 5 ways energy can be transferred

  • Mechanically
  • Electrically
  • Through heating
  • Via infrared radiation
  • Via light or sound waves
• Kinetic energy formula


  KE = 1/2mv²
• Weight formula


  w = mg
• Units for weight


  Newtons (N)
• Gravitational potential energy formula

  Ep = mgh
• Transfer between kinetic and gravitational potential energy


  1. As an object rises, KE is converted to GPE

  2. As an object falls, GPE is converted to KE
• The transfer between KE and GPE is mechanical
• As an object rises, KE is converted to GPE. As an object falls, GPE is converted to KE
• The amount of GPE gained is equal to the amount of KE lost
• Internal energy


  The total energy stored by the particles making up a substance, comprised of kinetic energy stores and potential energy stores
• Specific heat capacity


  The amount of energy required to raise the temperature of 1kg of a substance by 1°C
• Conduction


  1. Takes place in solids

  2. As one end is heated, kinetic energy of particles increases

  3. Particles move faster and collide more

  4. Other particles also vibrate faster

  5. This repeats through the object as kinetic energy is transferred between particles

  6. Overall, we say that it is thermal energy being transferred
• Metals


  • Have a high thermal conductivity as they conduct energy well when heated
• Fluid


  A substance in which the particles are free to move around, either a gas or a liquid
• Convection


  1. Takes place in liquids or gases

  2. As fluid is heated, particles gain kinetic energy and move further apart

  3. This causes the fluid to become less dense and rise above any other cooler, more dense fluid

  4. As the fluid cools it becomes more dense and sinks back down

  5. If this process happens in a limited space it can create a convection current
• Power


  The rate at which energy is transferred or the rate at which work is done
• Watt (W)


  The unit of power
• Biofuels should be carbon neutral, meaning they absorb the same amount of CO₂ when growing as they release when burned
• In reality, biofuels are not carbon neutral as trees may be cut down, so no longer absorb CO₂, and the processes to harvest, process, and transport biofuels also release CO₂