No matter how well a car engine is built, it sends heat out through its exhaust and its radiator.
Why must some of the fuel's heat always escape? Why can no engineer design the waste away?
Burning fuel packs energy into one small, very hot place inside the engine.
For every bit of that energy to become useful work, none of it could spread into the cooler metal and air around the cylinder.
So some of the input heat must end up spread into the cooler surroundings instead of becoming work.
The exhaust and the radiator are not design mistakes. They are the doors the spreading energy leaves through.
A better built engine narrows the wasted share.
Spread-out arrangements vastly outnumber concentrated ones, and that never lets the share reach zero.
Q: A natural-gas power plant boils water to spin a turbine. Explain why the plant must send some of its fuel's energy into the river water it uses for cooling, no matter how well it is engineered.
The plant's burner packs energy into one small, very hot place.
Spread-out arrangements vastly outnumber concentrated ones, so some of that energy spreads into the cooler surroundings.
The cooling water is where the spreading energy leaves the plant.
However well the plant is engineered, some of the fuel's energy must spread into the cooler surroundings; the cooling water carries it away.
Q: An online video claims a tuned engine turns all of its fuel's heat into useful work. Explain why the claim cannot be right.
For the claim to hold, none of the fuel's heat could spread into the cooler surroundings.
But energy and matter drift toward the arrangement that is overwhelmingly most likely, and spread-out arrangements vastly outnumber concentrated ones.
So some of the input heat must end up spread into the cooler surroundings instead of becoming work.
The claim cannot be right: no device converts all the heat it takes in into useful work.
Why must a motorcycle engine send some of its input heat into the surroundings?
Odessa says: 'Even a flawless engine must let some input heat spread into the cooler surroundings.' Is she correct?
A ship's diesel engine is built and maintained with zero flaws. What must still happen to some of the heat it takes in?
Why can no device convert all the heat it takes in into useful work?
An engineer halves an engine's wasted heat with better parts and insulation. Which statement is correct?
A coal power plant's cooling towers send clouds of warm vapor into the sky. What do the towers show about the plant?