Well, when I was a kid I thought cats and dogs were the same species, just that dogs were male and cats were female.
I can't beat daguin's for his, uhh, retro-ness... but when I was a kid we didn't have LED's, except maybe on really expensive stereo equipment.. so I really didn't have a chance to develop that theory... I read up at the library on how lasers work, and all they had were books describing ruby lasers, so that's all I knew about until a friend of mine bought a <5mw keychain pointer in the early 90's for something like $100.
Anyways, since this thread is completely off track, I've had the following types of burns: incendiary, high voltage discharge, explosives, soldering iron burns covering more than 2 square inches cumulatively, molten metals, molten polymers, molten rock, molten glass, acid burns (sulphuric, nitric, hydrofluoric), alkali burns (sodium hydroxide, potassium hydroxide), light burns (lasers, sunburn, fresnel lens), and frostbite (dry ice, liquid nitrogen, atmospheric exposure in a mountainous environment).
If anyone can think of any other types of burns, I'd like to hear about them as I'd like to try whatever activity I might be at risk of them.