The Leidenfrost effect occurs when a liquid is exposed to a surface so hot that it instantly vaporizes part of the liquid. It’s typically seen with a drop of water on a very hot pan; the drop will slide around, nearly frictionless, upon a cushion of its own vapor. You can see the effect when plunging a hot object into a bath of liquid, too. This is what happens when you quickly dunk a hand in liquid nitrogen (not recommended, incidentally) or when you drop a red hot steel ball into water like above. In this case, the object is so hot that it gets encased in a layer of water vapor. If you could maintain the temperature difference necessary to keep the vapor layer intact, you could move underwater at high speeds with low drag, similar to the effects of supercavitation. (Image credit: Paul Pyro, source)
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This week NASA released two new images of the shock waves surrounding T-38C jets in free flight. They’re the result of NASA’s new adaptations of the schlieren photography technique, which has let scientists visualize shock waves (in the lab, at least) for more than a century. To celebrate, I thought it would be fun to demonstrate some of the data engineers can extract from images like the one above. So I’m going to show you how to calculate how fast this plane was flying!
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Planet Saturn, August 5, 2007, observed by the Cassini space probe from a distance of approximately 2,469,771 miles (3,974,711 kilometers). (NASA)
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Moon Facts: The Moon is moving approximately 3.8cm away from the Earth each year.
A perpetual motion machine is the key to free energy creation.
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Rutilated Quartz Sphere
Cobaltoan Calcite - Aghbar Mine, Bou Azzer, Tazenakht, Ouarzazate Province, Souss-Massa-Draa Region, Morocco