HARNESS THE AWESOME POWER OF STATIC WITH THE CLASSIC LEYDEN JAR
I built a Leyden jar in three minutes to produce sparks. I lined an old plastic 35mm film canister lined inside and out with aluminum foil. A wire runs from screw on top touching the inside foil. Another wire runs from outside foil to a gap almost touching the screw. Some thin pieces of wire are also on the screw and fanned out to act as static antennas.
Hold a pvc pipe in a cotton cloth and with other hand rub pipe past antennas. Every stroke makes a loud spark between the wire and screw gap. Pvc and hand don't touch the Leyden jar.
One strip of foil outside, one inside. Wire from inside foil almost touching wire from outside foil. Add frayed thin wires for static collectors to the inside wire.
Use solid-core wire for the inside and outside wires. Use multi-strand wire for the static collectors and unweave the strands and fan them out.
I made my little 35mm one a little fancier by having the inside wire go to a screw, which comes out of a hole in the cap of the film canister. The white thing is just a piece of wire insulation, with multi-strand wire untangled and fanned out to collect static. The foil and wires were attached to the foil and the Leyden Jar with Scotch tape only. The static collectors is just wrapped around the screw, but I put a nut on it just for kicks.
Here's a video it in action:
Tiny jar equals tiny spark. Imagine the huge spark you could get by lining a garbage can with foil! Even after a spark this tiny thing acts as a capacitor and still has stored electricity which must be discharged by touching the gapped wire to the screw or else you'd get a shock by touching it.
Yes, bigger jar means bigger spark. How about more or thicker foil (the dielectric)? Well, what if instead of measly foil I filled the jar with salt water? I did just that with my next few Leyden jars:
It took me 10 minutes from walking in basement and starting building to getting sparks. It's easier on dry days with low humidity. Sine days I can get one spark per wipe. Some days it takes five or six. The larger the Leyden Jar, the more wipes it takes to spark.
The beast on the left is a daily water Leyden Jar. The spark takes a while to build up (lots of wiping the PVC with wash cloth) but it is larger and a lot louder!
Here is a scary, but true scenario: a battery slowly discharges it's electricity. Think of a flashlight. A capacitor discharges instantly. Think of a camera flash. In a non-existant "perfect" capacitor, the capacitor would fire instantly and emit 100% of its charge, leaving 0% energy left.
However, in the real world dielectric relaxation causes a brief delay in the firing of the capacitor. Worse yet, dielectric absorption stops the capacitor from emitting 100%, meaning it stores a small amount above 0% after firing. In a regular dry capacitor there can be 3% of the charge left after firing. In a wet electrolytic capacitor the left over charge can be a whopping 15%!!!
The result of all this? When the little, dry Leyden Jar fires it is pretty "empty" afterward. The wet, salt-water filled electrolytic Leyden Jars on either side can fire a huge spark, and then zap your hand with 15% charge if you touch them afterwards! Ouch!!
I can use the PVC pipe to force the in inside and outside wires to touch and get closer to 0% charge (there is a small spark when this happens) but even then, if left alone the charge can reorganize and zap a human hand when touching it!
Think of the tiny (yet much more efficient) capacitor in a stun gun. Then look at the salt-water filled behemoth on the left in my photo. I made a Leyden Jar out of a 1 gallon container: I fired it once and immediately disassembled it so no one would get hurt by it.
Every time I touch my back paw to my ear I get zapped! Too bad I don't have a tail: its dielectric absorption would give me stun-gun claws! Meow.
