🔍 Key Concepts

• energy conversion in engines (what an internal combustion engine is designed to do) • difference between thermal energy (heat) and mechanical energy (motion/work) • how an engine makes a propeller or crankshaft turn

💭 Think About

• In an internal combustion engine, what useful output do we actually want to get from burning fuel? Think about what moves or turns. • Does the engine mainly store more heat, create a new kind of ‘combustion energy,’ or change the fuel’s energy into another practical form? • On a vessel, what kind of energy ultimately drives the propeller and moves the hull through the water?

✅ Before You Answer

• Identify which option describes motion or work rather than just heat or chemical reaction. • Eliminate any choice that simply repeats the idea of burning or heat without changing it into something useful. • Ask: Which type of energy turns the crankshaft, gears, and propeller to move the ship? That’s the one you want.