Thermal conductivity is the ability of a material to transfer, or move, heat from one object to another. Cloth, for example, is a poor conductor of heat—heat moves very slowly through it from one side to the other. That's why a heavy blanket keeps you warm. It traps the heat in.
But you know what is a great conductor of heat? Metal. And there's no greater proof of that, than this:
The phenomenon where a person's tongue gets stuck to a metal pole in winter is all about thermal conductivity. The instant that a warm tongue touches that freezing pole, heat is quickly pulled from it into the metal (heat always tries to move to an area that is coldest). The saliva on the tongue freezes and bingo—that person is stuck! It all happens very fast.
So why bring this up? Aside from the fact that the science is pretty interesting, it's also a perfect introduction to a heartwarming story of wild animal rescue.
Finch Found Frozen
You see, it's not just people who get stuck to metal objects. It happens to animals, too. That's what happened when a finch decided to land on a metal fence on the property of Nelson Wilson, a farmer in Caldwell, Idaho. Mr. Wilson was out feeding his horses when he noticed the little bird frantically trying to fly away. He guessed that the finch had first landed on a heated water tank, which had melted snow on top. When it moved its now wet feet to the cold steel fence, thermal conductivity took over. The water on its feet froze and bingo—it was stuck!
That's where our kindly hero stepped in. First, Mr. Wilson gently wrapped his hand around the bird to try and warm up its feet. Then he decided to speed the process along by softly blowing his warm breath across his feet. If you look closely, you can see the ice melt away under his breath. Finally, with a little nudge, the bird's feet are free and off it flies!
Our favourite part? When Mr. Wilson says, "Here we go, little birdie. Go ahead and fly away!" Awwww. That's about as heartwarming as it gets, right?
Watch the video for yourself right here.