American physicists have managed to do the impossible - to force the water to boil without the formation of bubbles. They picked up the materials with such a surface, which lowered the value of the point Leidenfrost water up to a hundred degrees Celsius. This technology will help the crafters to design such a Board, which will significantly reduce the friction of the vessel on the water.

What the Leidenfrost effect, knows every housewife, even if she had never heard such phrases. And this is only a condition in which fluid in contact with the body is considerably hotter than the temperature of the boiling point of the liquid, creates an insulating layer of steam and protects it from rapid boil. As they say, all is simple and clear.

In everyday life the Leidenfrost effect is the easiest way to watch during the cooking process: after all, to estimate the temperature in the pan frequently were splashing water. And if the temperature is reached, or have already surpassed the Leidenfrost point, the water will gather in drops that will be "slide" on the metal surface and evaporated longer than if it occurred in less-heated pan. That is, if this effect is observed, then you can start pancakes or roast meat.

Scientists engaged in the study of this effect, established an interesting feature. The fact that the evaporation of a liquid when it occurs without the formation of bubbles. And all because of the evaporation process is only at the phone, not all volume of liquid. Guilty of all that the very boundary layer pair - it is the heat insulator, which does not give the liquid to be heated all at once.

However, if the temperature of a heated body suddenly falls below this point Leidenfrost (by the way, for water, it is usually a little less than 200 degrees Celsius), the saving "wrapper" from the vapor disappears. As a result, the liquid comes into contact with a solid and very hot surface, the rate of heat transfer increases sharply and it ends its explosive boiling-up. Bubbles at the same time, sadly, are formed.

Scientists dealing with the friction of ships on the water, which reduces the speed of traffic and, therefore, increases their costs, has long wanted to reduce the value of the point Leidenfrost for water - at least until its temperature of boiling, or better still lower. Then the friction body of water on the border of two phases will occur stable vapor layer, which is the most friction reduced in several times. But so far their attempts were unsuccessful - too difficult was to make this reasonable idea to life.

And recently, researchers from the University of Massachusetts, it seems, has finally been able to solve the problem. It is interesting that at first they actually did a very different work - tried to increase the efficiency of cooling systems for powerful computers. In the work it was about giving the surface microrelief, in the result of which was to improve the boiling heat transfer between a liquid and a solid.

To find out, how it occurs, and what the surface is better engineers worked with the special samples of silicon with different degrees of roughness. And here it was found out that the more uneven surface, the more improved heat transfer. So per square centimeter managed to reach the thermal conductivity in 208 watts, while the rough surface exceeded smooth six times.

While practices experimented with silicon different degrees of roughness, theorists did not waste any time and made a model of this process. In the end, they learned that similar improvement of heat transfer is a quite natural phenomenon - it improves it on the surface with marked microstructure because of the action of capillary forces. Here researchers struck a non-trivial idea - maybe the structure of rough surface can reduce the value of the point Leidenfrost for water?

This idea immediately decided to implement in practice. The researchers conducted a series of experiments in which used a metal sphere. First they were heated, and then just dropped into the water. The trick was that some of these areas before diving pre-processed or chemical coatings, or giving the mikroteksturoy, to give objects a water-repellent properties. All the processes that occurred during the study, were recorded on video.

And that's what eventually happened - rough heated balls managed to reduce Leidenfrost point for water is almost two times, i.e. up to its boiling point. The footage video clearly shows that the liquid in contact with the sphere surrounded by insulating layer of steam. It boils evenly, without bubbles. And only at 100 degrees Celsius!

However, researchers are confident that they will lower the value of the point Leidenfrost water even lower. However, while this possibility exists only on paper. However, scientists are planning a new series of experiments, for which specially selected special texture of the surfaces of the spheres. And if they are successful, then the ships for the first time might have a chance to overtake the planes....