I was watching an XKCD “What-If” video recently and Randal off-handedly mentions the title fact as a given. Upon a further Google search I see explanations about why sound moves faster in liquids than gasses but nothing for my specific question. Is there an intuitive explanation for that fact or is it just one of those weird observable facts with no clear explanation
Imagine the liquid as a road, and the sound travelling through it as a runner on said road. Now, sound is faster than the road, because road isn’t moving anywhere. But if we replace the road with one of those airport speedwalking walking pads (kinda like escalators but flat on ground), now the ground is moving, but as luck would have it, the runner is now moving even faster. The more you speed up the pad, the faster the runner moves, even if the runner themselves has not increased their speed.
Weird stuff, but it does make sense. :)
This analogy has nothing to do with why fluids can’t flow faster than their internal speed of sound