Energy Stores and Transfers Vocabulary

Energy Stores

• Scientists use specific names for different types of energy stores.
• Main energy stores:
  • Gravitational potential
  • Elastic
  • Chemical
  • Kinetic
  • Magnetic
  • Electrostatic
  • Nuclear
  • Thermal
• Gravitational potential energy: Higher when the object is higher from the ground.
• Elastic potential energy: Stored in stretched or squashed objects.
• Chemical energy: Stored in chemical bonds (e.g., fuel, food, batteries).
• Kinetic energy: Stored in moving objects; increases with speed.
• Magnetic energy: Stored in magnetic objects.
• Electrostatic energy: Stored in charged particles.
• Nuclear energy: Stored in the mass of an atom's nucleus.
• Thermal energy: Higher when the object is hotter.

Energy Transfers

• Four main types of energy transfers:
  • Heating
  • Electrical
  • Radiation (light)
  • Mechanical
• Energy transfer involves an energy store.
• Examples:
  • Heating relates to thermal energy stores.
  • Electrical relates to electrostatic and chemical energy stores.
  • Radiation relates to kinetic energy stores.
  • Mechanical relates to kinetic and potential energy stores
• Energy can be transferred from one place to another.
• Friction converts kinetic energy to thermal energy.

Sankey Diagrams

• Sankey diagrams visually represent energy transfers.
• Energy cannot be created or destroyed; it is only transferred.
• Energy transfers can result in useful or wasted energy stores.
• Key terms:
  • Gravitational Potential energy: Stored energy due to position/height.
  • Elastic Potential energy: Stored energy in stretched/squashed objects.
  • Kinetic energy: Energy stored in a moving object.
  • Chemical Store: Energy stored in chemical bonds.
  • Electrical energy: A transfer of energy involving flowing electrons.
  • Electrostatic store: Energy in charged particles.
  • Light energy: Visible electromagnetic radiation.
  • Sound energy: Energy caused by particle vibration.
  • Heat energy: Energy transferred through hot objects.
  • Thermal store: Energy stored in hot objects.

Energy Efficiency and Dissipation

• Energy is conserved; it is never lost or gained.

• Energy can be "useful" or "wasted" during transfers.

• Wasted energy is dissipated to the surroundings.

• Law of conservation of energy: Energy can only be transferred.

• Efficiency Calculation: $Efficiency = (Useful \, energy \, output / Total \, energy \, input) * 100$%

• Example efficiency calculation:

  • A drill uses 400 kJ electrical energy, outputting 300 kJ kinetic energy.
  • Wasted energy (heat) = 400 kJ - 300 kJ = 100 kJ