Above the Boiling Point

Hello, scientists!

Again, I'm sorry for not posting something yesterday or the day before. Homework (among other things) have kept me busy recently, so while I try to make this a daily blog, don't hold me to any promises I didn't make.

Anyway, chances are you, at one point, have wondered how it feels to fly. If you have, you're not alone. However, it actually turns out that it's impossible not to fly. You are always hovering above the ground at an atomic level. This also means that you don't really touch anything. The sensation of touch never is triggered by an object, but instead by the magnetic force between your atoms and the object's atoms. Dream come true!

Except, not really. You probably want to fly with a visible amount of space between you and the floor without a device. To that science says, "Good luck." Humans just aren't meant to fly or hover. Too bad. On the other hand, not only you can also make something fly on its own, you can do it in your very own kitchen.

That "something" is water. That's right, you can levitate droplets of water with only a saucepan and a stove. To understand this, let's review how water reacts to heat. It starts off frozen, an ice cube. As the tempurature increases to 32 degrees Fahrenheit, it melts into its pure liquid form, water. At 212 degrees Fahrenheit, it boils into steam, and that's (basically) the last step. However, at 379* degrees, something incredibly cool will happen.

This tempurature is named the Leidenfrost point. At this temperature, the droplet of water will actually be protected from direct contact from the pan by a thin** layer of water vapor under the droplet. The heat also causes the water droplets to coalesce. These two factors prevent the droplets from evaporating for a longer time. These balls of water also skitter around the pan due to them being riding on a cushion of steam.

Lead was used in a dangerous experiment. This experiment consists of (don't try this at home) dipping a wet finger into molten lead. Because there is a layer of steam from the water on your finger between you and the lead, you won't get burned. At least not right away.

Because of this layer of steam, it makes water of droplets possible to actually climb uphill. All that it needs is a surface that has grooves in the right direction. Which means in theory, you could make a maze with correctly positioned grooves. If you dropped water droplets into this maze, they would skitter, like in the saucepan, but in a specific direction, and turn when needed. Eventually, the droplets would solve the maze. Which is exactly what happened at the University of Bath.

Pretty cool, huh?

Anyway, that's it for now! Comment on stuff I got wrong or missed and suggestions for next time. Just a warning: you shouldn't receive any blog updates until Sunday. Sorry. Then, we'll probably do something related to biology. Tune in then!

Until next time,
Ben's jamin'
Benjamin

P.S. Make sure you check out John's math blog at http://johncooksmathblog.blogspot.com.

*This is a rough estimate; it's not exact.

**Thin means .1mm of vapor at the edge of the droplet and .2mm under the center.