Learn: Energy Transfers and Conservation

Welcome!Today we'll learn about energy transfers and conservation. Energy is all around us, and understanding how it's stored, transferred, and conserved is key to understanding physics!

What is Energy?Energy is the ability to do work or cause change. It can exist in many different forms, such as kinetic, thermal, or chemical energy. Energy is never created or destroyed; it is only transferred or transformed.

Energy StoresThere are several ways energy can be stored:Kinetic energy — Energy of a moving object.Gravitational potential energy — Energy stored in an object due to its height.Thermal energy — Energy stored in a system due to the movement of particles (heat).Chemical energy — Energy stored in bonds of substances like fuels or food.

Energy TransfersEnergy can be transferred from one store to another in different ways:Mechanically — By a force doing work (e.g., pushing or pulling).Electrically — By an electric current transferring energy.By heating — Energy transferred due to a temperature difference.By radiation — Energy transferred as waves, such as light or sound.

Conservation of EnergyThe law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed. The total energy in a closed system remains constant.In real-world systems, some energy will always be dissipated (spread out) as thermal energy, often due to friction or resistance.

EfficiencyNot all energy is usefully transferred. Efficiency measures how much of the input energy is transferred to useful energy stores. It is calculated as:Efficiency = (Useful energy output ÷ Total energy input) × 100%

Review Time!Great work! You've learned about energy stores, transfers, conservation, dissipation, and efficiency. Let's test your understanding with a few questions.