Energy Transfers and Stores

• Energy exists in different 'stores'.
• Energy cannot be created or destroyed.
• Energy can be transferred, dissipated, or stored.
• Energy can remain in the same store for varying durations, from fractions of a second to millions of years.
• Energy transfers occur continuously during system changes, modifying how energy is stored.

Examples of Energy Transfers

• A boat moving through water converts chemical energy into kinetic energy.
• Heating water in an electric kettle involves electrical energy increasing the internal energy of the element, which then raises the water's internal (thermal) energy and temperature.
• In a swinging pirate ship ride, kinetic energy converts into gravitational potential energy and vice versa.

Four Types of Energy Transfer

• By heating
• By waves
• By electric current
• By a force moving an object

Potential Difference (Voltage)

• It measures the energy given to charge carriers in a circuit.
• Measured in volts (V).
• It is the voltage between two points that causes electric current flow.
• Energy is 'given-out' by the material causing a decrease in the internal energy of the material.
• Infrared radiation from the Sun is emitted into space.

Work

• 'Work' is the scientific term for energy transfer.
• Examples include a grazing cow, a firing catapult, and a boiling kettle.

Transfer Diagrams

• Boxes represent energy stores.
• Arrows indicate energy transfers.
• Example: A child at the top of a slide has gravitational energy, which transfers to kinetic and internal energy as they slide down.

Sankey Diagrams

• Starts as one arrow that splits to show energy transfer into different stores.
• Useful when the amount of energy in each source is known.
• The width of the arrow is proportional to the amount of energy.