This memory aid covers Memory Aids within Efficiency for GCSE Physics. Revise Efficiency in Energy for GCSE Physics with 19 exam-style questions and 4 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 10 of 13 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
Topic position
Section 10 of 13
Practice
19 questions
Recall
4 flashcards
🧠 Memory Aids
The leaky bucket analogy: Imagine carrying water from a tap to your garden in a bucket with holes. You fill it with 100 litres (input), but only 40 litres reach the plants (useful output) — that is 40% efficiency. The leaked water (wasted energy) cannot be recovered. Every device is a leaky bucket; your job is to calculate how full the garden gets.
Formula — "Useful over Useless total":
- Efficiency = Useful Output ÷ Total Input (remember: U.O.T.I.)
Sankey diagram tip: The useful arrow always points straight through (to the right). Wasted arrows bend downward. The thicker the downward arrows, the lower the efficiency — it is visual.