The Principle of Conservation of Energy
- The Principle of Conservation of Energy states that:
Energy cannot be created or destroyed, it can only be transferred from one form to another
- This means the total amount of energy in a closed system remains constant, although how much of each form there is may change
Types of Energy
Energy Dissipation
- No energy transfer is 100% efficient
- When energy is transferred, some of the energy is dissipated to the surroundings
- Dissipated energy is usually regarded as wasted energy because it cannot easily be used for a specific purpose
- Any energy not transferred for a useful purpose is wasted energy
- These are commonly in the form of thermal (heat), light or sound energy
- What counts as wasted energy depends on the system
- For example, in a television:
electrical energy ➝ light energy + sound energy + thermal energy
- Light and sound energy are useful energy transfers, whereas thermal energy (from the heating up of wires) is wasted
- Another example, in a heater:
electrical energy ➝ thermal energy + sound energy
- Thermal energy is useful, whereas sound is not
