We all know that applying your tongue to metallic outdoor objects on a freezing cold day is a bad idea. (In fact, a general rule of tongue is that it should never venture far from the polite confines of the oral cavity.)

Yet, every now and then, this happens:

Before we go about explaining how to un-stick yourself from one of winter’s favorite human traps, it may be a good idea to understand how this sort of thing happens.

A thin layer of mostly water sits on the surface of the tongue. When pressed against cold metal, that layer of water, depending on the temperature, can freeze. Quickly.

According to the Cornell Center for Materials Research (CCMR), it’s the metal that causes the freezing — it has to be at least 32 degrees F (0 degrees C). Anything colder, of course, will do the job in less time. The chances of getting stuck depend on an object’s level of thermal conductivity; basically, how much heat it can transfer.

Man with tongue stuck to metal sign post The aluminum used in sign posts is particularly adept at sucking the heat from a tongue. (Photo: DocJ2000/YouTube)

Metal objects tend to be very high in thermal conductivity. They can suck heat from a warm tongue in a hurry, quickly freezing that coating of moisture.

Or, in Cornell-ese: “For the water to freeze on your tongue, heat must be extracted from the water to lower its temperature to the freezing point. But your tongue is warm and your body continuously supplies heat to it through your circulating blood. So the material you touch must have a high enough thermal conductivity to extract heat faster from your tongue than it can be supplied by your blood.”

Rubber and plastic are much lower on the thermal conductivity scale and, unless you happen to be visiting Pluto, won’t be able to sap enough heat from a tongue to freeze it. That’s why, theoretically, rubber and plastic may be licked freely in winter. Ice is a little dicier, since its thermal conductivity is higher than plastic, but lower than metal.

More than most, aluminum, steel and copper are brilliant at stealing heat — and should be considered a no-tongue zone in winter.

That's all well and good until temptation strikes.

Getting free

So, how do you get out of the sticky situation?

First, don't lose your head. You won't lose your tongue — although, if you yank away too quickly, you might lose a painful portion of it.

It all goes back to the heat, The metal stole it from your tongue. You need to get some more.

The Canadian Red Cross recommends pouring warm water on the surface of the tongue, which should allow you to ease away from the metal. “If skin is torn off, treat it like an open wound,” the organization notes.

That’s assuming the incident took place in a public place where people are close at hand to assist. If you’re alone, in an isolated area, you won’t be able to call for help, for the obvious reason that your tongue is currently occupied.

In that case, breathe. Really, really breathe. The heat from your breath should help melt the afflicted area around the metal. Your hands could also rub up a little extra heat, allowing the tongue eventually to slide free.

If all else fails, you’re going to want to dial 911 and try to communicate the nature of your emergency without using your tongue. In cold, icy winter, it shouldn’t be so hard.

Operators have, no doubt, long learned to recognize the kind of emergency that’s described over the phone as, “Aweeeieeeeeeeise.