why does a car battery spark

Yes - they're confusing a spark with an arc. A spark is a splash of incandescent molten metal, and CAN happen with electricity, a la your car battery example, but they also happen when grinding steel, or biting into a wintergreen Lifesaver - an arc is a plasma with current flowing through it. Admittedly, there are some arcs that are _started_ with a spark, notably in welding.

And a corona is neither, unless you consider the air itself to be the other electrode. :-)

Cheers! Rich

Inductance really has very little to do with it, unless you're talking about a "spark coil". This is pretty obvious when you consider that before you make contact, there is zero current, ergo inductive reactance doesn't enter into the picture.

But the inductance in the load can certainly _prolong_ an arc, because, as we all know, an inductor opposes a change in current; this is where the "inductive kick" comes from.

Hope This Helps! Rich

It's not that - I just see very little point in sacrificing a battery to prove something almost everybody already knows. ;-)

Cheers! Rich

Three, if you count the stuff I did at age 7. ;-)

Cheers! Rich

I once saw a demonstration of some guy making "ball lightning" - he had a MONGO bank of submarine batteries and a couple of HUGE electrodes, and touched them together, made a BIG spark/arc, and some of the (fairly big, maybe 1/8" dia.) droplets of molten metal kind of skittered around on the floor.

Ball lightning, my lily-white ass. ;-)

Cheers! Rich

You do the same thing:

Judge Mental Please go away.

Ditto.

--
You can\'t have a sense of humor, if you have no sense!

And it is absolutely certain that you do not know one from the other, and the one you claim to be is likely not quite there either.

Watching the spark a shorted battery makes is not experimenting, it is an observation of an event.

The run a series of experiments, you would first perform a requirement analysis so the correct data can be collected. Then you have to develop a plan and a set of experiments or tests to make formal observations of.

Declaring that you watched your battery make a spark when you shorted it is not an experiment, it is a test and confirmation of already known facts, at best.

#0000 "steel wool" is flammable in air.

Iron wool will auto-ignite in air.

There are many sparks.

WRONG. Welding ALSO "starts" with an ARC. Even if that arc begins at a mere 1 mil from the surface, that is STILL exactly what happens.

Also, the Lifesaver is not a spark, and it is also not an "incandescent splash of molten metal". Nor is it a spark.

The Lifesaver is a piezo-luminescent response. The photon emission is from within the medium. There is no arc that connects to your teeth. There is no arc or spark at all, in fact. The photons originate in the molecular lattice of the medium that had pressure applied to it.

That was about one of the saddest guesstimonies you have ever given, boy. Still, you do not see me stating "Please go away", like the little wuss that you often turn into does.

Bwuahahahaha!

This dope is still using non-rechargeables.

Are you also still on an XT? Are you also still using Radio Shack carbon Zinc batteries?

Which can supply a greater short term shorted pole current flow, an alkaline or a rechargeable NiCad or Nmh or such?

See what making those petty little stabs at people get you, boy?

Your stupidity is EASY to scrutinize.

You both must have cheated at math, and excelled at parapsychology.

Except that your guesses are so blatantly off the mark, that most passed on to the next post in the thread after reading stupid assessments made by stupid assessment retards. Get off your retarded little high horses, boys.

Molten metal ball slinging is more like it.

I have seen ball lightning twice in my life. Once was three spheres that came off a lightning rod on a barn as we passed by in a top-down GTO. It floated around between the rod and the side of the barn and the ground, then they suddenly burst and disappeared like soap bubbles. Red and Blue. The other was on a highway in Kansa and was green and lit up the whole sky for over thirty seconds.

Sorry, but I am almost certain that your ass would be several shades short of matching a white Lilly.

SAT 800. How did you do?

John

There was no event until I made it happen.

Sounds like a great way to get very little done.

The fact that a 9-volt battery makes visible sparks sure wasn't "already known" to many people in this thread.

John

A brief short won't hurt an alkaline battery enough to matter.

And who "already" knew?

John

On Thu, 17 Sep 2009 09:17:39 -0700, Rich Grise wrote:

spark 1 (spärk) n.

1. An incandescent particle, especially: 1. One thrown off from a burning substance. 2. One resulting from friction. 3. One remaining in an otherwise extinguished fire; an ember. 4. A flash of light, especially a flash produced by electric discharge. 5. A short pulse or flow of electric current. 6. A quality or feeling with latent potential; a seed or germ: the spark of genius. 7. A vital, animating, or activating factor: the spark of revolution. 8. The luminous phenomenon resulting from a disruptive discharge through an insulating material. 9. The discharge itself. 2. A glistening particle, as of metal. 3. 1. A flash of light, especially a flash produced by electric discharge. 2. A short pulse or flow of electric current. 3. A quality or feeling with latent potential; a seed or germ: the spark of genius. 4. A vital, animating, or activating factor: the spark of revolution. 5. The luminous phenomenon resulting from a disruptive discharge through an insulating material. 6. The discharge itself. 4. A trace or suggestion, as: 1. A quality or feeling with latent potential; a seed or germ: the spark of genius. 2. A vital, animating, or activating factor: the spark of revolution. 3. The luminous phenomenon resulting from a disruptive discharge through an insulating material. 4. The discharge itself. 5. sparks (used with a sing. verb) Informal A radio operator aboard a ship. 6. Electricity 1. The luminous phenomenon resulting from a disruptive discharge through an insulating material. 2. The discharge itself.

[Middle English sparke, from Old English spearca. V., from Middle English sparken, from Old English spearcian.] spark'er n.

John

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What? the OP said a 9V battery didn't spark. I did the test.

So now I think it's an energy thing. How many joules can you see? Of course there's a time component too. Does that make it a power thing?

George H.

try

780, but the math part was way too easy. I did a lot worse english part...... you can probably tell from my posts.

George H.

I've read that a dark-adapted human eye can see a burst of around a hundred photons. You can certainly see a single alpha particle hit a phosphor, which isn't a very efficient transducer.

I've also seen the claim that cats can see single photons.

I can see a good green LED, in office light, from a couple feet away, at about 100 nA. That must be picowatts entering my eye. I'll have to try it in the dark.

John