[Cliff Miller] pointed out this incredible project from 2004. [John Pultorak]’s journey began in late 2000 when he decided to build a 60’s or 70’s era minicomputer. While gathering technical documentation, he found some interesting information on the Apollo Guidance Computer and felt that was the way to go. The AGC was the first integrated circuit computer ever built. Designed by MIT in 1964 it was constructed from ~5000 ICs, almost all 3-input NOR gates. [John]’s version uses late 1960’s 74LS TTL logic which gains him a 10 to 1 reduction in the number of ICs. A good thing when you have to do ~15K wirewrap connections. He also used flipflops and register chips instead of building everything from NOR gates. [John] essentially built the AGC three times: First, he coded a simulator in C++. Then, he imported the logic design into CircuitMaker to verify that it would actually work. Finally, he built the 3 by 5foot machine. He’s provided an amazing amount of documentation for anyone that wants to explore this device and the overview alone is well worth a look.
nasa290 Articles
Magnetic Movie
Magnetic field lines may be invisible to the naked eye, but they behave in ways that would amaze us if only we could see them. [Ruth Jarman] and [Joe Gerhardt] from Semiconductor wanted to make them visible for everyone, so they produced Magnetic Movie, a film that combines animations, theoretical models, and actual VLF recordings of the entire Earth’s magetic forces to create a film that shows magnetic fields moving and jumping through the air in living color.
The film is part art project and part scientific experiment, but we can enjoy it on both levels, as watching the path and motion of magnetic field lines is both beautiful and informative. Get a glimpse for yourself after the break.
Make Your Own Aerogel
Our own [Eliot] dug this one up from the grave. While the recipe has been online for a while, do you know many 10 year olds who made their own Aerogel, that wonderful insulator that’s essentially gelled air? [William] made some(cache) for his science project in 2002. He started with Silbond H5, a combination of ethyl alcohol and ethyl polysilicate. You can get the MSDS after a painless email registration on the Silbond website. After the gel is formed you have to soak it in an alcohol bath to make sure all water has been removed from the structure. Then the gel is placed in a drying chamber. Liquid CO2 is forced into the chamber to displace all the alcohol in the chamber and the structure. Once the the alcohol is gone the supercritical drying phase begins. The temperature is raised to 90degF and the pressure is regulated to 1050psi. At this point the liquid CO2 in the gel structure takes on gas properties (looses surface tension) and leaves the silica structure. All that remains in the chamber is your new Aerogel which is 99% empty space and 1000 times less dense than glass.
Of course, if you’re lazy, you can buy some here.
