Why is it that after you chew any kind of minty gum, and then drink water, the water feels like it’s ice cold in your mouth? The same thing happens if you drink water after you brush your teeth.
Its all relative; the mint warms your mouth up (so to speak) thus when you drink the water it *feels * ice cold.
Its kind of like when you walk in to a cool building after being outside in the hot sun all day. It feels really cold at first but after a while it levels out and feels normal again.
And why does orange juice taste so awful after the morning mouthwash?
Darth Nader’s question has been torturing me for years, too. When drinking orange juice immediately after toothbrushing, there is this terrible undescribable taste. One of the great phenomena I just can’t explain (although I have a certain hypothesis about it, but I ain’t gonna reveal it here )
Aaaah, I just saw this answered in Focus, a British science mag. Sadly, I’m at work and it’s not. I’ll try again later.
I can’t answer the orange juice question, but I can tell you about mint. Menthol and the other “cooling” chemicals directly stimulate the nerve receptors that detect cold (much as capsaicin stimulates the “heat” receptors[or is it the pain receptors? can’t remem,ber]). When you drink water, you get an extra dose of “cooling.”
I remember reading this in Science News; I can’t get to the article at work, but Science News subscribers can find the article at www.sciencenews.org (search under “cold” and “receptor”).
OK, I’ll take a guess at the OJ question; toothpaste contains a load of artficial sweetener (as well as sorbitol or xylitol, in many cases). When you drink (sour) orange juice, it tastes really terrible in comparison.