On Fri, 14 Nov 2008 11:21:37 +0000, sparky wrote:

I ran out of petrol last night on a roundabout and blocked the traffic trying
to get on it. When my boyfriend came to rescue me he showed me how to "limp
it" out of the way using the starter motor. He pulled out a thick rubbery lead
from something, put the car in gear and let the power in the battery do all
the work. I was amazed, but when we got home, after watching him check the
battery with his little pocket meter, I was confused. Why didn't this powerful
battery set fire to such a small pocket meter when it had so much power in it?
I know the battery had loads of power left because I tested it by laying one
of his long screwdrivers across the lead terminals. It was so powerful that I
ended up melting one of them and damaged his screwdriver. Before I could ask
anything he sent me inside. The screwdriver was a long and thin one, but
thicker than the skinny wires on his pocket meter, so why did it get so hot
and cause such a massive spark? When he came in I asked him again, but he
refused to tell me, saying I should leave electrics to the experts. This
morning, after he left for work, I went back into the garage to do an
experiment. I found some thin wire similar in thickness to the wires on his
pocket meter and connect the ends to the battery. It melted before I could
disconnect it, so what's going on here? I had to pull it off with some
cardboard in my hand because I would've had a nasty burn without it. It really
was that hot, and it looked like it was getting hotter. It even started to
melt the battery's plastic. Do some wires have something in them to stop them
getting so hot? Why are the wires going to my kettle cold? Why do boyfriends
treat their girlfriends like idiots? We're the same age (22) but he talks to
me like I'm only half that age sometimes, so that's why I'm asking here. Am I
in the right newsgroup?

Hi,

Firstly, let me apologise for some of the responses you got here. LL
is correct. You need to know more about these things before playing
with car batteries. A lot more.

People are generally pretty relaxed about batteries but wouldn't dream
of playing with high voltage stuff. But believe me, car batteries may
be only low voltage but can deliver quite a lot of current, creating a
lot of heat very quickly if you short circuit them as you did.

Firstly, wait until your boyfriend has settled down. Remember, you
just destroyed a favourite screwdriver. Then ask him if he'll spend
some time explaining the basics to you. As someone else noted, he may
not know much or may not be a good/patient teacher. At a guess, he's
not totally ignorant on electrical stuff - he at least owns a meter.
And you're at least tech-literate enough to find your way into this
forum. On a personal note, if he won't help or at least point you to
help, flick him. You need to at the very least understand the concepts
of voltage, current, resistance, power and a relationship known as
Ohm's law. Remember, Google is your friend. Include words like
'tutorial' in your searches.

Please, for safety sake, do not experiment with high voltage (like the
wall outlets) or high current (like car battery) devices until you
understand clearly what you were doing wrong. There's no magic
involved. But there are some potentially lethal hazards.

John


PS: Sorry guys if I've upset you by encouraging a 'blond' but I happen
to know several intelligent blonds. Some are quite smart in their own
fields and even able to learn. This one is at least asking questions
(albeit a little late in the piece...)!