Seen at science museums, maker faires, and all over the internet, Singing Tesla Coils combine science and music in the most fantastical and memorable of ways. But how do they work? From Physics Buzz:
Sound waves are vibrations of the air around us, which you can make just by clapping your hands or talking. Pitch is just the number of times the air vibrates per second. Higher frequency, higher pitch. Tesla coils are a combination of circuits that output thousands to millions of volts. That high electric field arcs up and out of the coil, filling the air with sparks and making it possible to light up fluorescent lights wirelessly. Certain types of Tesla coils, like the one used here, are putting out hundreds of sparks per second, with a rest between each spark. That’s already a lot like a sound wave. Each spark is pushing on the air and can create a sound. Change the frequency of the sparks and you get an equal frequency wave, hitting your ears like a note of music. The creators had to find a way to move seamlessly between frequencies to make the notes sound distinct, instead of just playing the whole scale.
Above, tesla coils “sing” the Inspector Gadget theme by ArcAttack, who were the first to use this technology in a live performance in late 2005. Watch more singing tesla coil videos at Know Your Meme. Related links: the tesla coil and Nikola Tesla, who invented it around 1891.
In the archives: more electricity, more instruments, and things that glow.
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.
Need a battery-powered, modular, humanoid robot with strong legs and an amazing array of built-in cameras to help set up habitation on Mars for pioneering astronauts? NASA’s got you covered. Meet Valkyrie.
"The space agency’’’s new Valkyrie — a 6 foot 2 inch tall (1.9 meters) robot with a glowing NASA logo on its chest — bears an uncanny resemblance to Marvel’s superhero Iron Man, but this space age automaton was built for work, not comic book heroics. A team of engineers at NASA’s Johnson Space Center in Houston, Tex., designed and built Valkyrie in just nine months, according to press reports."
NASA created Valkyrie for DARPA’s upcoming Robotics Challenge Trials on December 20-21, 2013, where it will be in competition with 17 teams from around the world including NASA JPL’s RoboSimian, Carnegie Mellon University-NREC’s CHIMP, and Japan’s SCHAFT.
There are always more robot videos in the archives.