---
title: Physics FAQs
date: "2001-09-08T12:00:00Z"
categories:
  - links
wp_id: 1671
description: I share highlights from the sci.physics FAQs, including why energy is not always conserved, how hot water can freeze faster than cold, and why mirrors swap in-out rather than left-to-right.
keywords: [physics, sci.physics, mpemba effect, energy conservation, thermodynamics, optics]
---

The [sci.physics FAQs](http://www.faqs.org/faqs/physics-faq). Incidentally, energy is not conserved. Hot water freezes faster than cold water. And mirrors don't swap left-right -- they swap in-out.