Conservation of Emergy

• Conservation of energy


  Energy cannot be created or destroyed, it can only be transferred between stores
• Energy stores


  • Thermal energy
  • Kinetic energy
  • Gravitational potential energy
  • Elastic potential energy
  • Chemical energy
  • Magnetic energy
  • Electrostatic energy
  • Nuclear energy
• Energy transfer by rolling a ball up a hill

  1. Energy transferred to kinetic store as ball begins to roll

  2. Energy transferred to gravitational potential store as ball reaches top of hill

  3. Energy transferred back to kinetic store as ball rolls back down
• Kinetic energy


  0.5 x mass x velocity^2
• Gravitational potential energy


  mass x gravity x change in height
• Efficiency


  Useful energy / Total energy
• Useful energy stores in a phone

  • Light
  • Sound
• Wasted energy in a phone

  • Heat
• Efficiency will always be below 1 as nothing is 100% efficient
• Energy generation methods

  • Non-renewable (fossil fuels)
  • Renewable (solar, wind, hydroelectric)
• Non-renewable energy sources provide a lot of energy but are bad for the environment, renewable sources are better for the environment but more expensive