SCIENCE HOBBYIST  |
BALL LIGHTNING  |
GOOD STUFF  |
NEW STUFF  |
SEARCH
  ALSO SEE: even better balls

Bigger, Better Balls

Matt "The Tube" Crowley

June 23, 2004

 

I discovered the joys of zapping strange things in the microwave oven some time ago. I progressed to the Christmas ornament and pretty much stopped there. Somewhere along the line, I had learned that whatever was being zapped needed to be electrically conductive to produce that distinctive buzzing sound and lightning-like glow.

 

Because I had been keenly interested in Kevlar, epoxy, fiberglass, and resin composite technology for some time, I happened to have on hand a small amount of carbon fiber. Most people are familiar with carbon fiber as a woven fabric, usually in a cross-hatched weave. I knew that carbon was a semiconductor, so I unwove a patch of the woven fabric and placed a number of "tows" of carbon fiber in the microwave. Nothing much happened: Usually I would get a tiny white burning glow from one end of the bundle of black fibers. Just to be experimental and cover all bases, I decided to "nuke" a sample of another kind of carbon fiber: carbon "veil."

 

 

Even people familiar with fiberglass and composite construction techniques may not be familiar with veil. A veil is a nonwoven mat of fiber that is usually used as a final, top fabric layer on top of heavier (usually woven) layers of fabric. Perhaps the most common use of veil is in antistatic dryer sheets. It is also being used in ground-cover sheets as synthetic mulch. Because the fibers in veil are very fine and randomly oriented, it helps to create an even texture for an even-surface finish.

 

I got very lucky one day while at Boeing Surplus, which is located south of where I live here in Seattle. I got a huge roll of the stuff for $100. Pricing out a similar quantity from Fiberlay (also here in Seattle), I realized that a similar quantity would have cost about $1200 retail! I have never seen carbon fiber for sale at Boeing Surplus before or since.

 

I nuked a small piece of carbon veil and found that it ignited almost immediately. At this point, I was simply placing whatever "target" on the revolving glass plate and cooking it. I learned that carbon veil would "burn," but it simply did not produce that great of a display. I set aside my microwave experimentation for some time.

A year or two later I read an article in Fortean Times about ball lightning. I had been interested in ball lightning since reading about it in one of Phillip Klass's early books. He had suggested that many UFO reports could actually be instances of people who had seen ball lightning. One aspect of the story in Fortean Times that really caught my attention was the suggestion that people could make their own ball lightning in the microwave oven! I eagerly reviewed the websites listed, but I did not try it myself for fear that I would damage my nuker. Eventually I got a lucky break.

 

I had seen Bill Beaty demonstrate an FET-based charge-sensing device at a Seattle meeting of Dorkbot (dorkbot.org), an electronic hobbyist club. I was impressed by the elegant simplicity of his creation. I spoke to him afterward, and he told me that he was going to donate some literature about Nikola Tesla to the Seattle Museum of the Mysteries. When I spoke to him again at the museum, he casually mentioned that he was the creator of the website "Unwise Microwave Experiments." Finally, I found someone with some real electronic knowledge to ask about microwave experiments! Excitedly I returned home and tried the classic burning candle/scorched toothpick method. While I was able to create plasma balls, I quickly realized several things. One is that you need to contain the plasma in an upturned glass container if you don't want to burn the ceiling of your nuker. Two is that the glass should be Pyrex. While you may find several brands of glass cookware, I have had generic brand glassware shatter or crack much more easily that real Pyrex. Real Pyrex is expensive, but the used stuff is commonly available in second-hand stores cheaply. I bought a nice lightly tinted baking dish the size of a small loaf of bread for $1.99.

 

One should remove the revolving glass plate and plastic "lazy Susan"-bearing support. This is done for two reasons. One is to minimize the air currents disturbing the target as it revolves. The other is that if one places an upturned glass bowl on top of a flat glass plate, something of a seal is formed between the glass plate and the bowl, which usually leads to a strong buzzing and vibration of the glass bowl. I believe this is due to hot, expanding air rushing out of the upturned bowl and simply the strong "buzzing" sound of the plasma ball itself. You will note this strong glass-on-glass rattling effect in one of the short videos that French investigator Jean-Louis Naudin posted on his website (http://jnaudin.free.fr/).

 

With the revolving glass plate and the lazy Susan bearing removed, you have a circular trough that surrounds the center spindle. If you place the upturned bowl such that it bridges this gap, you will have no nasty buzzing glass vibration.

 

I tried the candle method several times. I found the flame would tend to extinguish as it consumed the oxygen in the upturned bowl. If you let the plasma ball run for more that just a second or two, the candle will start to melt and make a real mess. Timing the burn-out of the toothpick with the live candle flame was tricky. The websites that I had found through Bill's microwave oven site all seemed to indicate that carbon or carbon ions were somehow mysteriously responsible. Luckily, I recalled my previous carbon veil experiments. Unlike my previous experiments, this time I simply covered the carbon veil sample with the Pyrex bowl. WOW! THE BIG BREAKTHROUGH!

 

Ladies and gentlemen, throw away your candles! Screw the toothpick! Once you discover how vastly cleaner and easier the method of using carbon veil is over the medieval candle and toothpicks, you will never go back. With carbon veil, there is no fire or smoke to worry about, no melted wax, and no toothpick futzing. Even methods using graphite rods such as those of Naudin are less elegant. According to Naudin, both his graphite rod and aluminum baseplate need to be of rather precise dimension, based on the wavelength of the microwave being produced by the magneto. Working with tiny graphite rods can also be frustrating due to their delicacy.

 

First of all, why the emphasis on veil as opposed to the more common woven fiber? I do not know for sure why veil works better than plain fiber so the following comments are simply theories of mine. For one thing, the individual fibers of veil are significantly finer than those of regular woven fiber. I suspect they act as better tinder for ignition because of their greater surface area. I suspect that veil provides more individual cut edges for the electrical charges to accumulate. Also, most nonwoven fabrics contain some sort of "binder," which is an adhesive of sorts to keep the fibers together until the final resin is added. Perhaps this binder burns more easily than pure carbon and acts as some sort of initiator.

 

In any event I have not been able to duplicate the success of veil with ordinary carbon fiber. I also got sidetracked for a while because I felt I needed an inert gas environment for the carbon to do its thing. As it turns out, inert gas is not needed at all!

 

So for all those who have never nuked anything stranger than a slice of pizza but who want to see microwave oven ball lightning, here is exactly how to do it:

 

1.     Obtain a patch of carbon veil. A square foot is probably enough for about 50 or 60 experiments. You will probably have to buy it from a roll that is 36 or 48 inches wide. The best retail places to obtain this semiexotic stuff are marine supply stores. Many boating supply stores sell only small repair kits, and those are almost always fiberglass so you may have to shop around. Some hobby stores will sell composite supplies, as carbon is becoming more commonly used in radio-controlled aircraft. In larger cities, check the old Yellow Pages under "fiberglass." If you live in the boonies, you will probably end up having to buy the stuff via the Internet. As of this writing, Fiberlay in Seattle is set up for Internet ordering and mail order delivery. Undoubtedly, there are other Internet suppliers.

2.     Obtain a large Pyrex baking or measuring bowl. Again, you will find other brands, but I recommend genuine Pyrex because of its greater temperature tolerance. Most second-hand stores have tons of used glassware and cookware.

3.     Obtain a small ashtray to act as a container for the target sample of carbon veil. It should be small enough to fit inside the Pyrex bowl. Strangely, I have found this is actually a fairly necessary piece of equipment. If you lay the carbon sample flat on the base of the microwave oven, it does not seem to work. I assume that the sample needs some height to intersect the standing waves. If you can't find an ashtray small enough you can use a ceramic spoon. These are often used in Asian restaurants and are usually available in Asian markets or restaurant supply stores.

4.     Remove the revolving glass platter and lazy Susan bearing from your nuker.

5.     Cut a 1inch by 2 inch rectangle of veil. I have found that there seems to be a minimum dimension needed for this to work. My bare minimum seems to be about 1 square inch, so I double this for a margin of success.

6.     Fold, cut, or crease the sample such that it stands up a little. A simple fold in the middle will tend to snap back flat, so you may need to rub the two halves of the fold a bit to allow the crease to become a permanent fold. This gives you a small "tent" that will stand up. Alternatively, go crazy with scissors and origami. All you need to do is have it stand up a bit.. You can also set the target piece so that an edge sticks out over the rim of the ashtray or spoon, but make sure the overhanging edge is not closer than about 1 cm to the upturned glass bowl to avoid any arcing from the carbon to the glass. Arcing can spoil the plasma creation and erode holes in the glassware.

7.     Set the ashtray with the carbon target in the trough that the revolving glass plate occupied, and then place the Pyrex bowl over the ashtray. The ends of the Pyrex bowl should span the lazy Susan trough. All you really need is for an air gap to exist between the floor of the oven and the lip of the Pyrex bowl so that the Pyrex bowl does not buzz and rattle while the plasma is present.

8.     Adjust the nuker's power setting to maximum. To be honest, I have not tested whether or not the effect would occur with lower power settings. I suspect it would not, because the lower power settings are really just pulses of full power interspersed with longer periods of no power in-between. I suspect that any plasma created would disappear as soon as the first off-power interval occurred.

9.     Adjust your power setting to maximum, then press Start.

The carbon should start "burning" within about 1 second. If you don't get an effect within 3 or 4 seconds, immediately open the door and let the glassware cool. BE SAFE: Use oven mitts! The primary danger of all this experimentation is getting burned from hot glassware. Even if a plasma is not created, the glass can get very hot very quickly.

If you do get a plasma, do not let the effect run for more than 1 or 2 seconds. I know the great temptation is to gaze at this miraculous event for as long as possible, but I can say from personal experience that this can easily result in shattered glassware-even Pyrex. If the glassware does shatter, be aware that it can leave very sharp needlelike shards of glass, some of which are so small and invisible you may discover them in a most unpleasant way. If you are unwilling to use gloves or mitts, place your hand an inch or so away from any glassware before you touch it to judge how hot it is. Your best bet while running consecutive experiments is to use two or more Pyrex bowls: Let one cool on the burner of a regular stove while nuking the other. Don't run water (even hot water) over hot glass, because you greatly increase the chance of glass breakage.

If you don't achieve ignition, you may need to use a larger piece of veil or position it differently in the ashtray. Having done this many times, however, I can happily report that the plasma effect is easily created and remarkably tolerant of small changes.

 

I have tried wadding up the target into balls, but I have never gotten this to work. Again, it may have something to do with the exposed surface area or sharply defined edges. As far as two-dimensional shapes of the target, I have tried only squares and triangles. My sense is that any more-or-less flat shape would do, as long as it is not lying flat on the base of the nuker or the ashtray.

 

Before I learned that one does not need an inert gas for the ball-lightning effect to work, I had tried both argon and helium as "shielding gasses." Sadly, I did not get a "neon light" effect from either of these two inert gasses. I have tried doping the bowl with a slurry of salt granules and water. This seems to produce a much brighter and more yellow plasma ball.

 

A few final thoughts: The carbon veil method is so much cleaner than the candle/toothpick method, and so little carbon veil seems to be consumed that for me it adds a new sense of wonder to the effect. As soon as the veil ignites and a plasma "sprite" jumps upward, the carbon stops burning. I do not have the electrical engineering background to explain why this happens. My guess would be that the plasma absorbs microwave energy better than the veil in the same way that food containing water gets hotter than the plate or bowl it is in. One problem with the candle method is that the candle flame continues to burn while the plasma is active. This tends to obscure the fact that the candle is really only needed to initiate the effect, not to sustain it. This "initiation" is demonstrated beautifully with carbon veil. Another candle shortcoming is sputtering. Often with the candle method, the flame will start a plasma several times before it initiates a sustained plasma. I believe this is because of air turbulence inside the bowl that tends to blow the candle flame around. With carbon veil, you never have turbulence issues. You also do not have to clean away soot and crud created by the candle flame.

 

I also find it interesting that the carbon veil does not actually burn in the same way as if you lit it on fire with a flame. The "ignition" seems to produce little if any smoke, and the "flame" is usually white and not yellow-orange as in a conventional flame. The "ash" that results is grayish and extremely delicate, so clearly some sort of chemical and physical change has taken place.

 

Amazingly, one can get numerous ignitions off the same carbon sample! Today I have gotten at least 30 ignitions from a typical 1 inch-by-2 inch patch! But remember, you must let the bowl and ashtray cool down between consecutive ignitions. This quality alone shows its superiority over the candle method!

 

I hope I have contributed in a positive way to the ball-lightning-at-home world. My guess is that this method will prove itself superior in due time and that candle burning will become a thing of the past. After having figuring out how to consistently create plasmas in the microwave oven I am currently working on ways to "dope" either the carbon or the glassware to produce different-colored plasmas.

More: Easiest BL Yet

 

My thanks to Bill Beaty for technical assistance and for posting this article on his website.

 

Matt "The Tube" Crowley

June 23, 2004

 

 




http://amasci.com/tesla/bigball2.html
Maintained by Bill Beaty. Mail me at: .
View My Stats