Quacks don’t echo: True/False?
I don’t mean incompetent medicos — their ramblings seem to echo around quite happily inside the heads of the gullible — but the noises made by ducks. Despite ducks being commonplace few people seem to have ever heard a quack echo. It’s rare enough, at least, to have bred the idea that quacks don’t echo at all.
To understand the absurdity of this claim let’s switch to thinking about light which, like sound, travels as a wave but is much easier to, er, visualise. An echo is just a reflection of sound so, transposing the problem from sound to light, we ask what sort of thing has no reflection? That’s right: if quacks don’t echo then that makes ducks the acoustic equivalent of vampires.
But the echoless quack is just as mythical as the bloodsucking undead. Quacks do echo, it’s just that it’s often hard to hear the reflected sound.
Some surfaces are better at reflecting light than others. There’s no need to wave garlic and crucifixes at a mysterious stranger if their image doesn’t reflect off black cloth — we know from experience that dull black things don’t reflect much light. Similarly, with sound you find that some surfaces reflect much better than others. Hard ones give a good crisp echo, while soft ones muffle the echo. That’s why mountains and unfurnished rooms give such a good echo, and part of difficulty hearing the echo of a quack is that you don’t often find ducks in these situations.
Another problem is the sound of the quack itself, which increases in volume from start to end. Those who have considered the problem carefully (O brave new world that has such people in’t!) think that the early part of the echo is drowned out by the later part of the quack, and the later part of the echo then blends in with the quack and isn’t recognized for what it is, a mere reflection of the original.
As a moment’s reflection will tell you, ducks aren’t special and their quacks must echo. To think otherwise is just quackers.