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The title says it all: this blog features physics videos found everywhere on the web: animations, demonstrations, lectures, documentaries.
Please go here if you want to suggest other nice physics videos, and here if I mistakingly infringed your copyrights. If you understand French, you'll find a huge selection of physics videos in French in my other blog Vidéos de Physique.

Wednesday, 26 September 2012

Solid Nitrogen, Vacuum Cooling and Dry Ice

What happens when you decrease the pressure around a liquid? It boils. Water boils at room temperature once the pressure is low enough. What is interesting is that this decreases the temperature of the liquid. The fastest molecules escape, leaving the slower ones behind. Using this trick with liquid nitrogen, it is possible to create solid nitrogen at a temperature of -210C. We then poured the solid and liquid nitrogen mixture onto a tray of water. The surface of the water became so cold that CO2 solidified out of the atmosphere on its surface. Then, since CO2 does not pass through the liquid phase at atmospheric pressure, it was propelled on the water surface by jets of gas as it sublimed. Huge thanks to the Palais de la Decouverte. Music by Kevin MacLeod of Incompetech.com (Mirage)

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