P1 Energy — Section Overview

Energy is the currency of physics. AQA GCSE Physics organises this section around three big ideas: stores and transfers, useful and wasted energy, and the physics of fuel and power generation.

What this section covers

Sub-topic	Key ideas
P1.1 Energy stores and systems	Eight stores; four transfer pathways; conservation principle
P1.2 Calculating energy	KE = 0.5 mv²; GPE = mgh; elastic PE = 0.5 ke²; specific heat capacity
P1.3 Energy efficiency	Useful vs wasted; efficiency = useful/total; Sankey diagrams
P1.4 National and global energy	Renewable vs non-renewable; fossil fuels; nuclear; wind, solar, hydro

Core principles

Conservation of energy — energy cannot be created or destroyed, only transferred between stores. This is the single most important statement in the whole section.

Dissipation — in almost every real process, energy spreads to the thermal store of the surroundings (through friction, air resistance, sound). Dissipated energy is not gone — it just becomes harder to use again.

Efficiency — every device wastes some energy. Efficiency is a number between 0 and 1 (or 0 % and 100 %). No device can exceed 100 % efficiency.

Why energy matters globally

The section ends by zooming out to the national grid and the planet. You need to compare energy resources on reliability, cost, environmental impact and how quickly they can be switched on (response time). Non-renewable fuels (coal, oil, gas, nuclear) supply energy on demand but have environmental costs. Renewables (solar, wind, hydro, tidal, wave, geothermal, biofuels) are lower carbon but often intermittent.

Exam focus

• Show all working when using energy formulae — marks are awarded for substitution.
• Draw and label Sankey diagrams with arrows proportional to energy values.
• Give specific comparisons when asked about energy resources — never say "better for the environment" without saying why.