[Applied Science] has a new demo of an old 1970s patent for a portable generator that is both interesting and terrifying. The generator uses sodium and water, which, if you remember your old chemistry classes, will combust spontaneously. Turns out, though, it won’t if you draw power from it fast enough. Don’t draw enough power? BOOM, apparently. Check it out in the video below.Of course, lithium-ion batteries might catch fire, too, but this looks a lot more likely. The patent made some wild claims about how much you could draw from the device, but the video shows that practical results are somewhat less.Mechanically, a spinning metal disk has a sodium electrode extremely close to it. Water flows through the tiny gap, and electricity will flow between the two electrodes. This seems to be the only practical device built on this principle that is available to the public. We presume the original inventor built something, but there’s no record of it.The mechanical challenges are obvious. You have to connect to the spinning disk. In addition, as the sodium electrode goes away, you have to keep narrowing the gap. The patent mentions a spring, but doesn’t provide any details.We were expecting a slip ring arrangement, but the resistance was too high. That led him to use a liquid-metal contact with a homemade alloy of gallium, indium, and tin. The original disk was made with stainless steel. Later, he plated the disk with nickel to improve the conductivity.This doesn’t seem very practical and certainly seems unsafe, but it is still pretty cool. If you do try to duplicate this from the data on GitHub, he has some ideas on how to make it work better.Of course, there are sodium-ion batteries. We’ve even seen liquid sodium-based fuel.