The Doppler effect is the change in frequency of a wave as its source moves relative to the observer. The same effect that causes the change in pitch of a siren as it drives past is also used to estimate blood flow with ultrasound, measure the speed of a passing car, and even determine the motion of the stars. Doppler shift-based satellite navigation was also the first operational use of a system that eventually led to GPS.

When a siren or similar approaches I try to imagine the crunching up of the sound waves — the vehicle seemingly chasing after its own sound — and the stretching out of the waves as it heads past and into the distance. At least it makes it less painful on the ears.

The Doppler Effect

Remarkably, when we describe a noun we almost always, unconsciously, arrange adjectives in this order: opinion, size, age, shape, colour, origin, material, purpose.

If you try mixing them up in a different order it just doesn’t sound right. Compare, for example, a super little Italian coffee, to an Italian little super coffee. Or as Mark Forsyth points out in The Elements of Eloquence: How to turn the perfect English phrase, you can have a great green dragon, but not a green great one.

Ordering adjectives

Finding meaning and connections in unrelated things, you know, like faces in pieces of toast, the man in the moon and there are some amazing photos of clouds out there. Seeking patterns and meaning in random data is something we seem naturally inclined to do.

Also see narrative bias — how stories feel better than randomness.

Apophenia