heat

Showing 27 posts tagged heat

This street vendor makes popcorn with an explosive, pressure-cooking, popcorn cannon contraption, a centuries-old method. The video was filmed in Zhengzhou, China, but we’ve watched videos of this in South Korea, too. And of course, Mythbusters has looked into it, video below. Boom!

Related watching: Click to Enlarge: Popcorn, more explosions, and more videos of street vendors, including how this intricately-drawn melted caramel/sugar dragon is made.

via Boing Boing.

What’s happening when a match is lit? From Answers.com

Matches contain sulfur, glass powder, and an oxidizing agent as the components in the match head. When you strike a match, the friction due to the particles of glass powder rubbing together generates enough heat to convert some of the red phosphorous to white phosphorous, which burns in the presence of oxygen gas. The heat from the friction also causes the oxidizing agent to produce oxygen gas, igniting the small amount of white phosphorous. Once ignited, the oxygen gas fuels the flame while the rest of the sulfur catches on fire. Of course, this entire process happens in a fraction of a second.

…unless, of course, someone films it at 4000 frames per second, and then you really get to spend time with all of the macro, slow-motion details. Fascinating to watch, and a great conversation starter about fire prevention and safety tips, and using matches as tools.

Related watching: Why do hot things glow?, firefighter helmet cam, and Smokey and The Little Boy.

Thanks, @_thp.

The Leidenfrost Maze, designed and built by Carmen Cheng and Matthew Guy at the University of Bath, demonstrates how Leidenfrost droplets can be self-propelled in a controlled way by the jagged texture of the hot surface.

And what exactly is the Leidenfrost Effect? From PopSci:

The basic idea is, when a liquid comes in contact with something really hot—about twice as hot as the liquid’s boiling point, although it changes on certain factors like the size of the drop—the liquid never comes in direct contact with the surface; vapor acts as a barrier that keeps the two separated. When you flick drops of water on to a pan to check the heat, that skittering you see and hear is because of this effect.

Cheng and Guy made the aluminum block maze to inspire and share science with local school kids, though we’re guessing every school around the world would love a physics demonstration kit like this.

There are more excellent physics videos in the archives. 

via PopSci, thanks @kvetchup.