Electrostatic Generator Project Starts With Molten Sulfur

A modern recreation of von Guericke's electrostatic generator

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.

A round-bottom flask containing sulfur being heated in an oil bathAll 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.

38 thoughts on “Electrostatic Generator Project Starts With Molten Sulfur

  1. Please be safe when melting sulfur. It’s flammable and the fumes can kill. The safety equipment in this video looks inadequate and there should probably be at least a disclaimer that has to be clicked through with affirmative consent before viewing (if the video is allowed to stay up at all).

    1. So, you must be a safety inspector as well as a lawyer to offer up such advice. Please then provide your credentials. I’m sorry that you’re no longer in kindergarten to have all content sanitized to your liking without “affirmative consent”. In terms of videos available on the web, I can think of much worse that are not going to be taken down, and I hope this one won’t either. Grow up.

      1. I didn’t claim to have written the chemical safety literature for sulfur but I am capable of reading it (and, despite your self imposed limitations, I expect you are too). Why are you so afraid of a little responsibility to protect everyone?

        1. I am quite capable of reading the safety literature on sulfur. I’m not saying this is a good idea. I am saying that people should be able to express themselves. I’m pretty sure that’s an amendment somewhere. I don’t agree that “responsibility” means censorship.

          1. With rights come responsibilities. If you made a video that demonstrated removing asbestos without protection or taking an OD of Tylenol, you’d quite rightly face censorship without a disclaimer. That isn’t censorship, you’re still free to do it, you just have to do it a particular way.

            You sound like the “sovereign citizens” who complain that being arrested for driving without a license is a restriction of movement. The police and society don’t care about you travelling, they care that you’re doing something in a way that endangers others.

          2. > they care that you’re doing something in a way that endangers others.

            A driver’s license is just a piece of laminated paper. It means that you’ve passed a test to drive, but no guarantee that you actually are competent or responsible enough to be safe.

            You don’t HAVE to do anything in some particular socially approved way – it’s just that you have to deal with the consequences when things go wrong. A system like the driver’s license is meant for holding people accountable – but such systems always turn into gatekeeping where you have to pay the society a ransom to do something you could just do without an otherwise unimportant piece of plastic.

            Likewise, demanding that the author of the video should jump through hurdles when it’s the responsibility of the viewer is missing the point. The consent form doesn’t stop people from burning down their garages trying to melt sulfur. The “responsibility” that the author would take is an illusion, just a token gesture, because they have no control of other people – other than not posting the video in the first place, or omitting the process entirely. That would be self-censorship.

          3. Another great example is the Lichtenberg burning videos. No matter how many safety disclaimers you put in, people are going to go “I’m not going to go through that trouble, I’ll just be careful.” and then electrocute themselves. The only “safe” option is to censor the videos entirely, which is a method where just about anything can be “rightfully” censored in the name of public safety.

      2. YouTube already has community standards that demonetized videos they seem to encourage unsafe behavior. It’s not unreasonable to point out the risk the uploader presents for themselves or YT at large without resorting to the accusation that the suggestion is for personal sanitation purposes. They don’t have to be in kindergarten to recognize that we live in a litigious society and these are the rules. Seriously….why so hostile?

    2. Funny that i never read this kind of comments when guns are involved. Or am i being typically european?

      To be on topic again: very nice build. Far back on my todo list is building a wimshurst machine. They look so damned cool.

    3. Should the disclaimer requirement scale with the likely injury a video could cause? YES OR NO.

      Because the videos that talk about rice recipes would need disclaimers more than this, since they kill more people.

      Stop being a fool. “this guy jumped out of a plane! this video needs a disclaimer!”

    4. Listen, the advice on safety while melting sulfur is totally fair. Always be careful when experimenting. It is a process that can be dangerous if not done outside or with a fume hood. However, there certainly doesn’t need to be a disclaimer. I was melting sulfur in the garden when I was 13 and was bleaching flowers with sulfur dioxide. It really is not that bad

        1. I once thought of having some T-shirts made with the text “This T-shirt may cause cancer in the state of California”. The reason I didn’t is that I live in the Netherlands, and engish is getting mixed up in our own language too much already. But when translated to Dutch it doesn’t sound right either.

    5. I don’t generally mind if whoever is hosting a piece of content puts a footnote that they do not recommend trying things at home or that they do not agree with something expressed in that content, but this is nowhere near the kind of video most likely to inspire some idiot to hurt themself or others.
      Producing HF without knowing it by using computer dusters as flamethrowers comes to mind as something that people are much more likely to duplicate after watching a video. Oh, and let’s not let anyone talk about bathroom cleaning chemicals, since it’s too easy for someone to construe it as safe to mix them unless they start the video with a long disclaimer and a close up of all the warning labels. Or doing stupid things with cars; guess we have to take down all the videos about car meets and police chases anymore because David doesn’t like it.

      1. I think that presents a different engineering problem. How do you ensure the sulfur cools evenly enough to evenly coat the spherical object and not create a bald spot at the top.

        1. Rotate it slowly while cooling.

          Also, use several coats and then sandpaper it spherical afterwards. Chuck it in a drill or lathe, and make a jig to cut a spherical ball.

          (There are sphere cutting jigs available on eBay for inspiration.)

      1. Depends on how strong printed sulfur is, but it has the benefit of being infinitely-recyclable since it’s a pure element. Maybe foundry patterns? Lost-sulfur casting? House-fumigating while printing? The possibilities are endless.

      2. One thing I’ve seen suggested is bathtubs and shower bases. It’s quite bacteriostatic, and at least in western Canada they have so much elemental sulfur sitting around they’re building pyramids the size of small towns with it, just sitting out in the open, because it costs more to ship it than anyone would pay for it.

  2. The electrifying machine I built was a commission for the Royal Institution in London, more specifically for an upcoming Christmas lecture in chemistry. I can only recommend everyone to watch these lectures on youtube. The audience consists of children accompanied by their parents. In the lecture, every few minutes something explodes or catches fire. They show how to make black powder, build a fire cracker and a simple rocket, or how to start a fire by pouring glycerin on potassium permanganate. It is just such show experiments that inspire the next generation of scientists, as it always has been and always should be. And, of course, there are no safety instructions whatsoever. The responsibility for the children lies with the parents, not the experimenter. We don’t need safety fanatics. Next thing you know, life itself will be plastered with warnings, because it always ends fatally.

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