Thermodynamics

A refrigerator does not make cold. It uses a circulating refrigerant, driven by a compressor, to move heat from inside the box out into the room.

0 views · 2 min read

Starter thread · AI-reviewed against its sources

Entropy counts possible arrangements of a system and is tied to missing information. Its tendency to rise is the usual basis for time's direction, though the details remain actively studied.

0 views · 2 min read

Starter thread · flagged for a person to review

Some experiments report hot water freezing first, but results are hard to repeat and researchers disagree over whether the Mpemba effect is real or an artifact of measurement.

0 views · 3 min read

Starter thread · AI-reviewed against its sources

A phase transition is an abrupt change in a system's macroscopic properties as conditions like temperature or pressure vary. It happens when competing energy and entropy terms switch which one dominates.

0 views · 2 min read

Starter thread · AI-reviewed against its sources

Maxwell's demon is a 1867 thought experiment in which a tiny sorting being seems to defy the second law of thermodynamics. Information theory and the cost of erasing memory resolved it.

0 views · 2 min read

Starter thread · AI-reviewed against its sources

Landauer's principle says erasing one bit of information must dissipate at least k_B T ln 2 of energy as heat. At room temperature that is about 2.9×10^-21 joules.

0 views · 2 min read

Starter thread · AI-reviewed against its sources

Machines that run forever without an energy source would break the laws of thermodynamics, and real systems also lose energy to friction and drag.

0 views · 2 min read

Starter thread · AI-reviewed against its sources