Energy Stores, Systems, Conservation, and Resources Study Notes

Fundamental Principles of Energy

• Energy is measured in units of $\text{joules}$.
• The Law of Conservation of Energy: Energy is neither created nor destroyed; it merely changes from one form to another.
• When energy is transferred from one store to another, some energy is always wasted, usually dissipating as heat (thermal energy).
• Thermal energy, internal energy, and heat refer to the exact same concept.

Energy Systems

• Definition of an Energy System: An energy system is defined as an object, or a group of objects, that transfer energy or have energy.

Energy Stores and Transfers

• Energy is stored in specific forms within objects and transferred between stores through pathways.

• Mnemonic Device: The sentence "most kids hate learning G C S E energy names" serves as a memory aid for energy stores and pathways:

  • m — Magnetic store
  • k — Kinetic store
  • h — Heat (thermal) store
  • l — Light (Pathways/Transfers, not an energy store)
  • G — Gravitational potential store
  • C — Chemical potential store
  • S — Sound (Pathways/Transfers, not an energy store)
  • E — Electrostatic store
  • energy — Elastic potential store
  • names — Nuclear store

• Comprehensive Breakdown of Energy Stores:

  • Kinetic Energy Store: Movement energy associated with moving objects. Example: A car.
  • Gravitational Potential Energy Store: Energy stored by an object due to its position in a gravitational field. Example: A parachutist.
  • Thermal / Internal / Heat Energy Store: Energy related to temperature and internal thermal motion. Example: A hot kettle.
  • Chemical Potential Energy Store: Energy stored in chemical bonds. Examples: A battery, food that we eat, and muscles within the human body.
  • Elastic Potential Energy Store: Energy stored in an object when it is stretched or compressed. Example: An elastic band.
  • Magnetic Energy Store: Energy stored due to magnetic fields. Example: A fridge magnet.
  • Electrostatic Energy Store: Energy stored due to static electric charges. Example: A balloon stuck to a wall.
  • Nuclear Energy Store: Energy stored within the atomic nucleus. Example: A nuclear power plant.

• Energy Transfer Pathways (Not Energy Stores):

  • Energy is transferred from store to store by pathways including:
  • Light: Energy transferred by light rays (not an energy store). Example: The sun.
  • Sound: Energy transferred by sound waves (not an energy store). Example: A radio.
  • Electric Current: Energy transferred electrically.

Knowledge Quiz and Energy Resources

• Renewable Energy Resources:

  • Definition: An energy resource that can be replenished and replaced as it is used (defining it merely as "you can use it again" is incomplete/incorrect).
  • Examples: Solar energy (light/sun), geothermal, tidal, wave energy, and hydrogen/hydroelectric power.

• Non-Renewable Energy Resources:

  • Examples: Natural gas, oil, coal, and nuclear power.

• Environmental Impact of Burning Fossil Fuels:

  • Gas Produced: Burning coal produces carbon dioxide gas (along with water vapour).
  • Environmental Consequences: The release of carbon dioxide leads to global warming, the greenhouse effect, and climate change.

• Wind Power:

  • Disadvantage: Wind power is unreliable because it won't always be windy.

• Thermal Radiation and Conductivity:

  • Absorption and Emission: The colour black is the best at absorbing heat radiation. It is also the best at giving out (emitting) heat.
  • Thermal Conductors: Metals are good conductors of heat energy. Copper is the best conductor of heat.
  • Electrical Conductors: Gold is noted as the best conductor of electricity.