speed of sound
"The speed of sound is like the speed of your car. It is not a fundamental quantity of Nature. You can change it at will (you can change the speed of sound by heating up the gas for example)."
"speed of sound is like plowing snow with a straight board, rather than with a veeplow, and the power required is correspondingly enormous."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.