Solved cryptogram
Heat moves from the warm thing to the cold one by itself, and never back without work.
Physics Facts, sourced to HyperPhysics, Georgia State University.
Solve it yourself
This fact is a cryptogram here: 68 letters over 21 different ones, graded hard.
Or go to the puzzle’s own page first.
What it means
Nothing in the accounting of energy forbids a cold room warming a hot cup. The second law of thermodynamics forbids it anyway, and it is the one law of physics that tells you which way time runs. A refrigerator does move heat the wrong way, and it has to be paid for in electricity, dumping more heat out of the back than it took from inside. That is why leaving the door open warms the kitchen rather than cooling it.
The claim comes from HyperPhysics, Georgia State University.
- SourceHyperPhysics, Georgia State University
- CollectionPhysics Facts
- Difficultyhard
- Length68 letters, 21 of them different
Nearby in the collection
The facts either side of this one.
- NISThard, 74 letters
- Royal Society of Chemistrymedium, 68 letters
- HyperPhysics, Georgia State Universitymedium, 71 letters
- HyperPhysics, Georgia State Universitymedium, 75 letters
About as hard as this one
Scored closest to it by the model behind our guide to solving cryptograms.
- HyperPhysics, Georgia State Universityhard, 76 letters
- NISThard, 74 letters
- NISThard, 73 letters
- U.S. Department of Energymedium, 76 letters