Something randomly occurred to me, which may well be beyond common sense for most people, but I had never thought about it before.
I was always told you shouldn’t drink really hot things (like hot cocoa or tea) through a straw, because they’d burn your mouth that way. It was one of those things that got ingrained as motherly wisdom, but on first blush, it makes absolutely no sense. How would something passing through a plastic tube make it hotter?
However, while drinking my toasty warm coffee, I noticing myself blowing on it, and two and two came together. Even if you don’t blow on it, the liquid at the bottom of the mug is much better insulated than the liquid at the top of the mug. The stuff at the bottom (assuming it’s not being stirred a bunch), has all of the liquid above it to insulate it from the colder air above it, as well as the mug insulating it on the sides and below. So, it would make sense then that the liquid at the top is cooler, as it’s not as well insulated and it’s transferring heat to the surrounding air. So, when you take a sip off the top, you’re getting coffee that has had some of the heat removed by the air around it, and you are basically taking a slice off the top of the coolest liquid. However, when you use a straw, you’re piping the most well insulated liquid (and therefore hottest part) directly into your mouth. Thus, burnt tongue.
Amazing how counter-intuitive folk-ish wisdom can make so much sense. Or maybe everyone else figured this out when they were five, and I’m just slow.
Now if someone could explain to me why eating apples, or apple derived products, gives me bloody noses the next day. Seriously. Anyone? Because it’s really annoying and I kind of like apples.