Cool science: Watch water droplets navigate a maze

From the American Chemical Society.

WASHINGTON — Have you ever seen a drop of water navigate a maze? It’s possible thanks to the same phenomenon that lets you know if a griddle is hot enough for pancake batter. Water droplets that dance and skitter across a hot surface instead of boil away on the spot are experiencing the Leidenfrost effect.

Understanding Leidenfrost — first described more than 200 years ago — helped engineers make more efficient steam engines. Today, scientists are using high-speed cameras to better characterize how superhot water behaves on metal surfaces. The investigation might lead to improvements in power generation. Watch the superhot dancing droplets here:

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43 thoughts on “Cool science: Watch water droplets navigate a maze

  1. Love the selective machining/texturing of the metal surfaces, to change the force vector of the resulting steam!

    • No attempt to measure additional heat or evaporation caused by being near (or on) an electrical device – if its on then it produces heat.

      Just like most other effects, one must consider all possible variables, not just the one the tester advocates.

    • I’m 99% sure that’s fake news. Real scientists have been unable to find any negative impact on humans from radio frequency electro-magnetic radiation.

  2. I didn’t know there was a name for this phenomenon. Thank you for posting this!

  3. Yes, I never knew the term Leidenfrost before now, but I knew instinctively why the water on a much hotter surface reacted the way it does. Very interesting how they discovered that they could harness the effect by machining the metal in acquiring the rotational energy. Will be interesting to see if this has any widespread application.

      • Incredibly inefficiently. The energy to do it is coming from boiling water. However, if you have a bunch of heat and nothing better to use it for, go right ahead!

      • Also used in steel rolling mills. As the hot steel is being flattened, they pour water on it to cover the steel with steam which then prevents oxidation. When I was a student over 30 years ago in an environmental class, we visited the Geneva Steel plant in Utah and got to watch this phenomenon.

  4. Anthony , just so you know, your next post, ” Our Canadian Friends”, is not found ?

  5. I love the Leidenfrost effect! I may get a t-shirt printed with ‘Leidenfrost was right!’ on it. That will confuse people.

    Now, if only these people who bring us science programs can explain selective hearing in cats, I will be happy.

  6. Superheated steam is extremely acidic, it attacks metal turbine blades, causing pitting, which causes a drop in efficiency.
    Read once where steam driven turbines only operate at about 50 percent efficiency because of the above. Good research, well worth it.

  7. People who design heat exchangers are familiar with the concept of film boiling. If the temperature between the two fluid is too high, a vapor film ensues which causes heat transfer to suffer greatly.

  8. that was awful – yeah, the science was in there but it was pitched to a 6 yr old and the ripped off content was not credited. like this bit:

  9. I remember about 50 years ago Scientific American had a wonderful column, The Armature Scientist. One column was on this effect – an experiment, a hot skillet and a water drop. What was the temperature where a water drop had the longest life? If I recall 50 to 70 seconds was possible. Too hot or too cold would shorten the life of the drop. Of course pressure is also a factor. In nuclear reactors a critical parameter is DNBR, departure from nucleate boiling – the place where film boiling begins and heat transfer drops dramatically, i.e. where the drop of water floats on the steam.

  10. And because of the Leidenfrost effect, you can grab things like frozen nitrogen ( for a bit) without damage…

  11. As I recall, it was the Leidenfrost effect that led to the melt-down at TMI-2. The operators turned off the safety injection system, allowing the fuel rods to heat up to above the Leidenfrost temperature. Eventually the operators turned the safety injection system back on but the surface of the fuel rods was too hot to be cooled by the water.

  12. It navigates as much as water “navigates” through a crevice.

    Path of least resistance.

  13. When I played the video, part way through I go a scam pop up saying I needed a critical firefox update. Did anyone else get that?

  14. Then there’s the lederhosen effect. Usually only seen during Oktoberfest though.

    • You can see during Oktoberfest! a mighty man you must be, i myself see only drifting smudges.

  15. I did a science fair project on this in 1978. Went to the International Science and Engineering Fair with it.

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