[Advanced Tinkering] needed a source of fresh ozone for some future chemistry related projects, and since buying an off-the-shelf unit would be, well, just plain boring, it was obvious what to do (Video, embedded below).
The concept of the corona-discharge ozone generator is pretty straightforward — a high-voltage AC potential is presented over a large surface area, such that any O2 in the vicinity has the chance to get a decent dose of electrons ripping it apart and enabling the formation of the desired O3.
The construction is quite simple, just a pair of cylindrical metal wire mesh electrodes, separated by a glass tube, with a second glass tube surrounding the whole assembly. The use of high voltage AC allows the discharge to form by capacitive coupling across the central tube, giving a very simple construction. A pair of 3D-printed PLA end caps complete the reaction vessel, although it is noted in the video that the PLA is not terribly resistant to the corrosive effects of ozone, and time will tell whether these go the whole mileage.
Feed oxygen from an external generator is pumped into one end cap, at the bottom, with ozone-enriched gas passing out the other end, at the top, giving the gas a more complex path through the assembly and maximizing the contact with discharge. It will be interesting to see what the produced ozone will be used for in these future projects.
These last few weeks we’ve all been reminded about the importance of washing our hands. It’s not complicated: you just need soap, water, and about 30 seconds worth of effort. In a pinch you can even use an alcohol-based hand sanitizer. But what if there was an even better way of killing bacteria and germs on our hands? One that’s easy, fast, and doesn’t even require you to touch anything. There might be, if you’ve got a high voltage generator laying around.
In his latest video, [Jay Bowles] proposes a novel concept: using the ozone generated by high-voltage corona discharge for rapid and complete hand sterilization. He explains that there’s plenty of research demonstrating the effectiveness of ozone gas a decontamination agent, and since it’s produced in abundance by coronal discharge, the high-voltage generators of the sort he experiments with could double as visually striking hand sanitizers.
Looking to test this theory, [Jay] sets up an experiment using agar plates. He inoculates half of the plates with swabs that he rubbed on his unwashed hands, and then repeats the process after passing his hands over the high-voltage generator for about 15 seconds. The plates were then stored at a relatively constant 23°C (75°F), thanks to the use of his microwave as a makeshift incubator. After 48 hours, the difference between the two sets of plates is pretty striking.
Despite what appears to be the nearly complete eradication of bacteria on his hands after exposing them to the ozone generator, [Jay] is quick to point out that he’s not trying to give out any medical advice with this video. This simple experiment doesn’t cover all forms of bacteria, and he doesn’t have the facilities to test the method against viruses. The safest thing you can do right now is follow the guidelines from agencies like the CDC and just wash your hands the old fashioned way; but the concept outlined here certainly looks worthy of further discussion and experimentation.
We know, we know – “Kirlian photography” is a term loaded with pseudoscientific baggage. Paranormal researchers have longed claimed that Kirlian photography can explore the mood or emotional state of a subject through the “aura”, an energy field said to surround and emanate from all living things. It’s straight-up nonsense, of course, but that doesn’t detract from the beauty of plasma aficionado [Jay Bowles]’ images produced by capacitive coupling and corona discharge.
Technically, what [Jay] is doing here is not quite Kirlian photography. The classic setup for “electrophotography” is a sandwich of photographic film, a glass plate, and a metal ground plate. An object with a high-voltage, high-frequency power supply attached is placed on top of the sandwich, and the resulting corona discharge exposes the film. [Jay]’s version is a thin chamber made of two pieces of solvent-welded acrylic and filled with water. A bolt between the acrylic panes conducts current from a Tesla coil – perhaps this one that we’ve featured before – into the water. When something is placed on the acrylic, a beautiful purple corona discharge streams out from the object.
It’s an eerie effect, and it’s easy to see how people can see an aura and attribute mystical properties to it. In the end, though, it’s not much different than touching a plasma globe, and just about as safe. Feeling a bit more destructive? Corona discharge is a great way to make art, both in wood and in acrylic.
[Steven Dufresne] of Rimstar.org is at it again with another very functional science experiment. This week he’s showing us how he made a large electrostatic motor, also known as a Corona Motor.
A Corona motor makes use of a cool
phenomenon called the Corona discharge, which is the ionization of a fluid
(in this case, air) surrounding a conductor that is energized. He’s done other high voltage experiments that take advantage of this, like his Ion Wind propelled Star Trek Enterprise!
The motor works by using an even number of electrodes on the motor, each electrically charged; positive, negative, positive, negative, etc.
Because each electrode is the opposite charge, they want to repel each other — but since the cylinder is electrically insulated, the charges have no where to go — instead the cylinder begins to rotate as the charges attract back and forth — when a positive charge on the insulation meets a negatively charged electrode, the charge is removed by ionization (creating the corona effect), and the cycle continues. The direction of rotation is determined by the angle of the electrodes. The motor can get going pretty fast but doesn’t have that much torque or power.