ICICLES GROW LONG AND THIN & THIS IS WHY
Posted by: Editor in CLIMATE WEATHER, WATER, WEATHER Add commentsWhy Icicles Are Long And Thin
Mathematical Physics Explains
How Icicles Grow
When droplets of melted snow drip down an icicle, they release small amounts of heat as they freeze. Heated air travels upwards and helps slow down the growth of the icicle’s top, while the tip is growing rapidly. Knowledge of the mathematical equations that govern icicle growth — the same that apply to stalactites — could help in the prevention of icicle formation on power lines.
Icicles can be dangerous and deadly, yet they can create some of the most amazing winter scenes. And for scientists, those winter scenes are playgrounds for discovery.
It’s on those playgrounds that experts in physics and mathematics are building their theories on what it takes to create an icicle.
We all know icicles form when melting snow begins dripping down a surface. But what scientists didn’t know is how their shape is formed. What makes each icicle different?
University of Arizona Physicist Martin Short turned to mathematics to find out.
“Icicles have a certain mathematical shape, and this mathematical shape is universal among icicles,” Short tells DBIS.
So what is the math behind an icicle?
“Here I’ve drawn the profile of an icicle. Here is the height, and here’s the radius … Here’s the profile here, and I’ve written the formula here. The height is proportional to the radius to the four-thirds,” he says.
What does the formula have to do with an icicle’s shape? “It kind of looks like a carrot,” says Short. “It starts out flat and then sort of up as you go.”
As water drips onto an icicle and freezes, it releases heat. The warm air rises up the sides of the icicle. Short says that warm air layer acts like a blanket that’s an insulator, and so the blanket is very thin near the tip and thick at the top. That allows the top to grow very slowly and the tip to grow rapidly — creating a long, thin icicle.
It’s the same equation scientists use to study stalactites in caves, but instead of water, stalactites are formed by the buildup of calcium left after the water evaporates.
“If we know the mechanisms by which stalactites form, well, we could better preserve our natural caves that we have here, and try to stop them from eroding,” Short says.
And now that scientists know how icicles are made, it could lead to breakthroughs to prevent them from forming on power lines and trees.