In this Daily Skinny, we will discuss something that we have all heard a million times from concerned mothers, teachers, parole officers or whomever. While it would be easy to go into the laws of thermodynamics, convection, conduction, etc. That would be dull. That is why we are here to tell you just The Skinny.
Many of us have been told in cold weather that we must wear a hat because around half (some people say up to 70%) of our body heat is lost through the head. This is great advice, except for one thing: IT ISN’T TRUE!
So why do people say it?
For one thing, they may believe this because the head/face is usually one of the only parts of the body that is likely to remain uncovered, and is likely to feel cold first. For people living in nudist colonies, this can be a problem in the winter. (I’d guess nudists have many problems in the winter) It makes sense that the uncovered part of the body would lose the most heat. This is true in principle, but nowhere near 50% of body heat is lost through the head. It is, in fact, much much much lower. In fact, it makes almost as much sense to insist that someone’s left elbow be covered in the cold. If you really want to get technical, the scalp does have more vascular surface area than other parts of the body, but the body also constricts vessels to control body temperature blah blah blah. The bottom line is that all things being equal, the head does not lose appreciably more heat than any other part of the body. For this and other reasons, you are far more likely to lose more body heat from your hands and feet than most other areas.
The really “smart” people will try to use “science” against you.
Incidentally, people who use made-up science to convince you of things are intellectually giving you a wedgie. Have you ever wondered what the world record for the most wedgies given at once is? Given that most people have two arms, I'd guess most people could handle giving two wedgies at a time. I'm sure there is someone in Zanzabar who was born with three arms who could even manage three wedgies at a time. (I hate 3 armed Zanzabarbarian bullies) Come to think of it, if you had a 3 armed Zanzabarbarian bully, a hook, a ladder, a bomb shelter, a stick of gum and three volunteers, I am pretty sure a talented 3 armed Zanzabarbarian could manage 4 wedgies at once. (You may need to draw a wedgie-diagram to figure this out.) In any case, I am thinking 4 might be the most physical wedgies given at one time. If you ever need a laugh, picture everyone in the U.K. receiving a massive wedgie all at once. Well it happened. I don't have pictures, but here is the evidence: Check out http://www.bbc.co.uk/weather/features/health_culture/wind_chill_effects.shtml This is the BBC giving everyone in the U.K. an intellectual wedgie. I guess checking facts in news stories isn't a big concern there.
Anyway, back to what I was saying. The really “smart” people will try to use “science” against you. They will tell you that “heat rises, and this causes nearly half of your body heat to be lost through your uncovered head. This is a common misconception, and is quite silly. If it weren’t silly, I wouldn’t be writing this. In the first place, no matter how many power drunk high school science teachers tell you that heat rises, it is not true. Heat is not a noun. Heat, or temperature is a property or description of an object. For example, the color blue. Blue is an adjective. You cannot have blue without involving a noun (an object). You can have a blue cup, blue paint, or blue sky. You can’t have blue and nothing else. Blue is a way of describing something else. Heat is the same way. You can have hot matches, hot air, or hot crossed buns, but you can’t have heat without an object. Heat cannot rise because “heat” as an object does not exist.
Warm air is less dense than relatively cooler air, and therefore rises above cool air. The same principle is true of water (until it starts to freeze at least). Since your body is constantly circulating fluids, gases, etc, there is no way for them to rise due to temperature differential. If “heat” really did rise, then the top half of your body would be much warmer than your lower half. An ear thermometer and a rectal thermometer would show vastly different temperatures. As we all know they give the same reading (take my word for it). This is because “heat” especially “body heat” does not rise.
The fact is that heat from your body is lost according to SURFACE AREA. It radiates in all directions equally. The skin on your head loses heat at the basically the same rate that the skin on your calves, arms, and pinky fingers do. The only way to lose half of your body heat through your head is if your head is GINORMOUS.