Although the basic concept of electrostatic attraction has been known since ancient times, it was only in the 17th century that scientists began to systematically investigate electrostatics. One of the first to explore this new field was Otto von Guericke, who constructed an electrostatic generator to help with his experiments. [Markus Bindhammer] has reconstructed this machine, which formed the basis for later work by the likes of Wimshurst and Van de Graaff. [Markus] kept his machine in an almost period-correct fashion.
Von Guericke’s machine consists of a sulfur ball mounted on a spindle that allows it to be rotated and rubbed against a piece of cloth. By doing so, the ball gains a charge that can be used to attract small pieces of material. [Markus] built a neat wooden frame with faux-antique carved legs and installed a handle, a spindle, and a belt-drive system to rotate whatever’s mounted on the spindle at high speed.
All of this is beautifully documented in [Markus]’s video, but by far the most interesting part of his project is the process of manufacturing the sulfur ball. If you’ve always wanted one, here’s how to make one: first, melt some pieces of pure sulfur in a round-bottom flask using an oil bath. Then, turn on your vacuum pump to remove any air or water vapor trapped inside the liquid. Once the liquid is nice and clear, let it cool down and solidify very slowly; the sulfur ball can then be released from its container by breaking the glass with a hammer.
While it sounds simple, we can imagine it took a bit of experimenting to get all those steps just right. The end result is a simple but useful machine to demonstrate basic electrostatics, which [Markus] is planning to use in science lectures. There are lots of interesting experiments you can do with static electricity, including building a basic motor.
Continue reading “Electrostatic Generator Project Starts With Molten Sulfur”
Lithium sulfur batteries are often touted as the next major chemistry for electric vehicle applications, if only their cycle life wasn’t so short. But that might be changing soon, as a group of researchers at Drexel University has developed a sulfur cathode capable of more than 4000 cycles.
Most research into the Li-S couple has used volatile ether electrolytes which severely limit the possible commercialization of the technology. The team at Drexel was able to use a carbonate electrolyte like those already well-explored for more traditional Li-ion cells by using a stabilized monoclinic γ-sulfur deposited on carbon nanofibers.
The process to create these cathodes appears less finicky than previous methods that required tight control of the porosity of the carbon host and also increases the amount of active material in the cathode by a significant margin. Analysis shows that this phase of sulfur avoids the formation of intermediate fouling polysulfides which accounts for it’s impressive cycle life. As the authors state, this is far from a commercial-ready system, but it is a major step toward the next generation of batteries.
We’ve covered the elements lithium and sulfur in depth before as well as an aluminum sulfur battery that could be big for grid storage.
When you think of the periodic table, some elements just have a vibe to them that’s completely unscientific, but nonetheless undeniable. Precious metals like gold and silver are obvious examples, associated as they always have been with the wealth of kings. Copper and iron are sturdy working-class metals, each worthy of having entire ages of human industry named after them, with silicon now forming the backbone of our current Information Age. Carbon builds up the chemistry of life itself and fuels almost all human endeavors, and none of us would get very far without oxygen.
But what about sulfur? Nobody seems to think much about poor sulfur, and when they do it tends to be derogatory. Sulfur puts the stink in rotten eggs, threatens us when it spews from the mouths of volcanoes, and can become a deadly threat when used to make gunpowder. Sulfur seems like something more associated with the noxious processes and bleak factories of the early Industrial Revolution, not a component of our modern, high-technology world.
And yet despite its malodorous and low-tech reputation, there are actually few industrial processes that don’t depend on massive amounts of sulfur in some way. Sulfur is a critical ingredient in processes that form the foundation of almost all industry, so its production is usually a matter of national and economic security, which is odd considering that nearly all the sulfur we use is recovered from the waste of other industrial processes.
Continue reading “Mining And Refining: Sulfur”
When we talk about emissions these days, we typically talk about cutting them back for the good of the environment. However, the climate system is a complex beast, and one we’re still learning to understand.
As it turns out, cutting back on emissions may have unexpected or undesirable effects. Some scientists are concerned that cuts to human-induced sulfur emissions may actually be warming the Earth.
Continue reading “Reduced Sulfur Emissions Could Cause Climate Shock”