Leidenfrost effect

[kgrant]

I was playing around the the other day putting snow on a hot stove top. The water would dance around and settle into a low spot on the stovetop. A drop the size of a dime would just sit there, not boil or anything. They would last a long time (at least a minute). I researched and I think this is called the Leidenfrost effect.

Found a video on youtube that shows it. The water part starts around 1:20

http://www.youtube.com/watch?v=QgWSr95eocU

Anyone else ever experience this?

Little picture of what is going on here.

http://www.restek.com/Technical-Resources/Technical-Library/Editorial/editorial_A023

 

[henkmeuzelaar]

Yeah. this behavior is fascinating to watch!

In fact, if one plots the time needed to completely evaporate a given quantity of water this way against the surface temperature, one will see that effective evaporation rates decrease at temperatures where the Leydenfrost phenomenon starts.

In other words, in this particular configuration maximum evaporation rates are not achieved at the highest temperatures, which is counter-intuitive.

 

[woodgeek]

This is the same reason you can 'safely' pour liquid nitrogen over your bare hand. (Just don't let it touch the hairy back of your hand, it will then wet).

 

[Big Al]

They showed that on an episode of Mythbusters. They wet their hands and were able to dip them into a vat of molten lead, albeit quickly, but no burns were suffered. Of couse they tested it with a hot dog first, but kudos to Adam and Jamie for having he stones to to try it with thier hands. Amazing.

 

[Dakotas Dad]

They showed that on an episode of Mythbusters. They wet their hands and were able to dip them into a vat of molten lead, albeit quickly, but no burns were suffered. Of couse they tested it with a hot dog first, but kudos to Adam and Jamie for having he stones to to try it with thier hands. Amazing.

As a reloader and bullet caster, I can say, no matter what the science, I would never do that. Not for nothing. Even if I was in the room when they did it. I sneezed once, and some "liquid" hit the smelt... It's called "lead tinsel", and if you are close when it magically appears, it hurts. A lot. Chicks dig scars and all.. but I have a spot on my arm that's pretty nasty, thank the lord my wife makes me wear a face shield when doing any of that type stuff..

 

[Shari]

I was playing around the the other day putting snow on a hot stove top............

I'm trying to figure out why you were doing this. Winters are long in Alaska????

 

[Big Al]

They showed that on an episode of Mythbusters. They wet their hands and were able to dip them into a vat of molten lead, albeit quickly, but no burns were suffered. Of couse they tested it with a hot dog first, but kudos to Adam and Jamie for having he stones to to try it with thier hands. Amazing.

As a reloader and bullet caster, I can say, no matter what the science, I would never do that. Not for nothing. Even if I was in the room when they did it. I sneezed once, and some "liquid" hit the smelt... It's called "lead tinsel", and if you are close when it magically appears, it hurts. A lot. Chicks dig scars and all.. but I have a spot on my arm that's pretty nasty, thank the lord my wife makes me wear a face shield when doing any of that type stuff..

I'm with ya there. I often think they have the coolest job on the planet, but there are things they do sometimes that make me reconsider my opinion on that. take the good with the bad I guess. YIKES

 

[kgrant]

I was playing around the the other day putting snow on a hot stove top............

I'm trying to figure out why you were doing this. Winters are long in Alaska????

Well, yes they are long! I am working on rebuilding/retrofitting and old severely under-fired stove that was full of creosote. So instead of scraping it out I stuck it outside and burned it clean. Get pretty bored standing around drinking beer watching flames shoot out the 4 feet of stack I stuck on it.

I wouldn't consider sticking my fingers in molten lead or pouring dry ice over my hand. I just thought the water not boiling part was neat. Now that I think about it I've seen it before when I was a kid hanging wet gloves/hats on the rack over the stove. They would drip onto the stove and do the same thing.