Energy

• Energy stores


  • Kinetic
  • Thermal
  • Chemical
  • Gravitational potential
  • Elastic potential
  • Electrostatic
  • Magnetic
  • Nuclear
• Anything that's moving stores kinetic energy
• All objects store thermal energy, the hotter it is, the more energy it has
• Anything that transfers energy through chemical reactions stores chemical energy
• Anything that has mass and is inside a gravitational field stores gravitational potential energy
• Anything that is stretched or compressed stores elastic potential energy
• Anything with electric charge that is interacting with another electric charge stores electrostatic energy
• Anything magnetic that is interacting with another magnet stores magnetic energy
• The nucleus of all atoms have nuclear energy that can be released by chemical or nuclear reactions
• Ways energy can be transferred


  • Mechanically
  • Electrically
  • By heating
  • Radiation
• Energy is always conserved, but it is not always in the way we want it to be, this is called wasted energy
• Energy is normally wasted by being transferred as sound or being transferred to heat
• Dissipation is where energy is lost to the environment
• Efficiency


  Useful energy out / total energy in x 100
• You should use a wooden spoon because it's an insulator and won't heat up very quickly
• A jumper keeps you warm because the heat doesn't transfer to the jumper very quickly
• Jumpers have small holes that trap air, and air is not a good conductor so it won't transfer the heat from your body to the surroundings
• Convection is one of the ways energy is transferred by heating
• Convection only takes place in liquids and gases, solids do not convect as they do not flow
• Properties of metals and non-metals


  • Metals: Conduct electricity, malleable, shiny
  • Non-metals: Rarely conduct electricity, brittle, dull, often gases