Remember when a homemade cloud chamber was a science fair staple? We haven’t participated for decades, but it seemed like every year someone would put a hunk of dry ice in a fish tank, add a little alcohol, and with the lighting just right – which it never was in the gymnasium – you might be lucky enough to see a few contrails in the supersaturated vapor as the occasional stray bit of background radiation whizzed through the apparatus.
Done right, the classic cloud chamber is a great demonstration, but stocking enough dry ice to keep the fun going is a bit of a drag. That’s where this Peltier-cooled cloud chamber comes into its own. [mosivers] spares no expense at making a more permanent, turn-key cloud chamber, which is perched atop a laser-cut acrylic case. Inside that is an ATX power supply which runs a Peltier thermoelectric cooling module. Coupled with a CPU cooler, the TEC is able to drive the chamber temperature down to a chilly -42°C, with a strip of white LEDs providing the required side-lighting. The video below gives a tour of the machine and shows a few traces from a chunk of pitchblende; it’s all pretty tame until [mosivers] turns on his special modification – a high-voltage grid powered by a scrapped electronic fly swatter. That really kicks up the action, and even lets thoriated TIG welding electrodes be used as a decent source of alpha particles.
It’s been a while since we’ve seen a Peltier cloud chamber build around here, which is too bad because they’re great tools for engaging young minds as well as for discovery. And if you use one right, it just might make you as famous as your mother.
Continue reading “See the Radioactive World with This Peltier Cloud Chamber”
From the windtraps and stillsuits of Dune’s Arrakis, to the moisture vaporators of Tatooine, science fiction has invented fantastic ways to collect the water necessary for life on desert worlds. On Earth we generally have an easier go of it, but water supply in arid climates is still an important issue. Addressing this obstacle, a team of researchers from MIT and the University of California at Berkeley have developed a method to tease moisture out of thin air.
A year after the team first published their idea, they have successfully field-tested their method on an Arizona State University rooftop in Tempe, proving the concept and the potential for scaling up the technology. The device takes advantage of metal-organic framework(MOF) materials with high surface area that are able to trap moisture in air with as little as 10% humidity — even at sub-zero dewpoints. Dispensing with the need for power-hungry refrigeration techniques to condense moisture, this technique instead relies on the heat of the sun — although low-grade heat sources are also a possibility.
Continue reading “Coaxing Water From Desert Air”
If there’s a chemical with a cooler name than “fuming nitric acid,” we can’t think of it. Nearly pure nitric acid is useful stuff, especially if you’re in the business of making rocket fuels and explosives. But the low-end nitric acid commonly available tops out at about 68% pure, so if you want the good stuff, you’ll have to synthesize fuming nitric acid yourself. (And by “good stuff”, we mean be very careful with the resulting product.)
Fuming nitric acid comes in two colors – red fuming nitric acid (RFNA), which is about 90% pure and has some dissolved nitrogen oxides, giving it its reddish-brown color. White fuming nitric acid (WFNA) is the good stuff — more than 99% pure. Either one is rough stuff to work with — you don’t want to wear latex or nitrile gloves while using it. It’s not clear what [BarsMonster] needs the WFNA for, although he does mention etching some ICs. The synthesis is pretty straightforward, if a bit dangerous. An excess of sulfuric acid is added to potassium nitrate, and more or less pure nitric acid is distilled away from the resulting potassium sulfate. Careful temperature control is important, and [BarsMonster] seems to have gotten a good yield despite running out of ice.
We don’t feature too many straight chemistry hacks around here, but this one seemed gnarly enough to be interesting. We did have a Hackaday Prize entry a while back on improvements to the Haber process for producing ammonia, which curiously is the feedstock for commercial nitric acid production processes.
Continue reading “Anyone Need a Little Fuming Nitric Acid?”
Producing ice without electricity just got a lot easier thanks to these engineering students from San Jose State University. Their system uses solar heat to facilitate evaporation of a coolant. When the sun goes down and the coolant turns back to liquid, its temperature drops drastically due to extreme pressure differences. The unit can produce 14 pounds of ice per day with zero carbon footprint. It has no moving parts and an entirely sealed system, this should mean that the only maintenance necessary would be keeping the unit clean.