Thermodynamics & Efficiency
📋 What it is
Every energy conversion wastes some as heat; efficiency measures how much useful work you actually get.
🗣️ Coach says
The laws of thermodynamics set the rules: energy is conserved, but every conversion loses some as waste HEAT — so no machine is 100% efficient. Efficiency is the fraction that does useful work. Improving it (LED bulbs, better engines, insulation) is one of the cheapest ways to save energy.
🧠 Memory hook
Every conversion wastes some heat → nothing is 100% efficient. Efficiency = the useful fraction.
😂 Giggle
What do you call a dinosaur that powers a generator?
A fossil fuel!
😲 Whoa!
An electric car turns about 90% of its energy into motion, while a gasoline car wastes most of its fuel as heat — a big reason EVs are so much more efficient.
✅ Quick check: Why can no machine be 100% efficient?
Say your answer out loud first — then reveal.
Every energy conversion loses some energy as waste heat, so some is always "lost" from useful work.
Thermodynamics guarantees waste heat in every conversion.
🧪 Try it! (2 minutes)
Feel a working laptop or charger — that warmth is energy "wasted" as heat, lowering its efficiency.