Final Jeopardy! category: PHYSICS (20-06-2010)
Final Jeopardy! clue: Discovered in the early 20th century, these 2 particles, 1 with a positive charge, the other a packet of energy, differ by a letter
The gist: Pretty different indeed, except in their spelling. Proton and photon have such similar names due to one part etymology and one part coincidence. First, the etymology: the Greek suffix “-on” is used to form the neuter singular of something, and can therefore signify a “unit” or a “single instance” of something. The coincidence is that Greek “proton,” meaning “first thing” and used for the particle because it was originally thought (incorrectly) that hydrogen, which had one proton, was the constituent of everything else. The Greek “photon,” on the other hand, means “light.” In Greek, the words aren’t as similar as they look in English, since “pr” consists of two characters, pi and rho (π and ρ), while “ph” is a single character, phi (φ).
The clue: A classic FJ! clue. Realistically, as long as you’ve heard of both a proton and a photon, you only need to know what one of them is to know both of them, since this is really more a word puzzle clue than it is a science clue.
In Jeopardy!: Proton and photon get just this one clue together (except for one where a contestant mistook one for the other). Individually, protons win out, having a little over twice as many clues as photons. Please try to remember that that letter makes a big difference.