Brilliant. So there's your 'well' for electrons.
I hadn't thought of a Leyden jar. Clever.
One of Franklin's favorite experiments was the "circle shock." To try this you need a circle of people holding hands and a charged Leyden Jar. Break the circle at one point and have one of the people with a free hand hold the bottom of the Leyden jar. Then have the other person with a free hand touch the top of the Leyden jar. If there is enough electricity in the Leyden jar, everyone in the circle will feel an electric shock! Be careful as large Leyden Jars can pack quite a wallop and knock you onto the floor. Anyone with a pacemaker should not be involved in a circle of shock experiment. The circle shock does teach you how electrical in nature we truly are.
..... franklin was easily amused. Here hold this! BZZZT.
Yikes! Never send a shock up one arm and down the other! It puts your heart in the path of the electricity, and there is a very good reason they shout "Clear!" to everyone when using defibrillators in medical dramas...
Not exaggerating here. Even a small shock can upset the heart rhythm, and if someone had any unsuspected heart problems they could die from it.
Leyden jars from film canisters are not too dangerous, but make them from something like a jam jar and they can be quite lethal, especially if charged from a static machine like a Van de Graaf generator.
I thought it was the amps that killed you - those shocks would only be in the milliamp range at most - no?
Your heart is basically both a muscle and a nerve. It expands and contracts by a cascading electrical pulse though the individual muscle cells. If you were to start an electrical pulse outside the normal rhythm you could cause the works to go out of sync; your heart just twitches instead of pumping blood and you die. You probably don't need a lot of amps to do that.
^^ I think it is something like .25-.5 amps directly over the heart.
"Leyden jars from film canisters are not too dangerous, but make them from something like a jam jar and they can be quite lethal, especially if charged from a static machine like a Van de Graaf generator."
This guy came to my junior high and did that with a whole circle of kids around the gymnasium.
He also had a tesla coil. He stood on a stool in a pie plate of water and wore gloves with metal finger tip points. He shot lightning from his fingers with the lights out while holding the tesla coil. Very cool.
I believe its around 50 mA. You get 50 mA through the heart at just the wrong time, and you can stop it.
Now, human skin has about 10 Megohms of resistance (when dry -- when wet it drops to like 200 ohms). So it can take some serious voltage to develop that much current through the heart.
However, a Leyden jar, charged up with a Van der Graaf generator, can hold several tens of thousands of volts. Not something you want to take chances with.
As a side note -- the high-voltage transformer in a TV can charge up to 30,000 volts -- but with not much current. However, if you touch that sucker, it can cause all of the muscles in your arm to contract quite quickly, strongly, painfully, and without control. You can get cut that way, and hurl the screwdriver in your hand across the room. Not to mention the blue cloud of cursing you'll find coming out of your mouth.
the official maximum safe current is only 10mA, IIRC from when I did my techy training (long time ago).
That's the number they use to figure out safe working voltages and such.
> One of Franklin's favorite experiments was the "circle shock.
When batteries were first invented I remember reading the king of france (?) had 7000 people shocked at once. He like to see them all jump up at the same time and fall.
It's good to have a well. Though I was hoping there would be stray electrons out there to put in it.
One of the episodes of Mythbusters was to determine if the Mayans created batteries out of terra cotta jars. The thinking is that with a few of them in series, you could wire them to a ceremonial display which shocked people. Voila - magic.
The terra cotta batteries didn't come out so well, so they wired up a cattle prod to the ceremonial display and had Adam try it (without telling him about the switch). He did, and got shocked - you could honestly see he was absolutely furious that they did it. You know that look someone gets when you play a practical joke on them but they don't think it's funny? (not quite "air costs money" furious, but seriously mad)
When Grant (who'd done the switch) wasn't on the next episode, I was sure he'd been fired.
The "evil" William Shatner
March 15th, 2007 5:14pm