Answer 2:
The power for the light bulb does not come from
the wire - it comes from the battery. The wire
simply provides the conducting path.
Your teacher
gave you only ONE wire? haha - this is a tricky
question , but you can still light the bulb. I bet
you think you have to have TWO wires,
right? So
that you connect one wire between the battery and
bulb on each side - well, you can do it with only
one wire! Here's how:
Look carefully at your
battery - it has two terminals, a positive and a
negative. On most batteries the positive terminal
sticks out a bit, and the negative one is flat, or
pushed in just a little bit. That way you can tell
which is which. The positive is where the positive
charge carriers come out, full of ELECTRIC
POTENTIAL ENERGY and the negative is where they
come back in, after doing their "work", to get
re-energized by the battery.
Now look at your bulb - it has two terminals
also, but they are a bit
hidden.
One terminal is where you would expect
it: at the tip of the bulb (the metallic pointy
tip, not the glass bulb). The other one is not so
obvious:
it is WRAPPED AROUND the base of the
bulb! If you look carefully at your bulb, you will
see a thin black or dark colored plastic ring that
separates the bottom metallic point of the bulb
and the metal collar that is wrapped around -
that's the insulation.
Now here's how to light
your bulb with only one wire and one pair of hands
(yours):
First strip off a few inches of the
insulation from one end of the wire very
carefully, so as not to cut the copper strands
beneath the thin plastic insulation. Then wrap the
bare wire securely around the collar of your bulb
(one terminal). Then touch the other end of your
wire to EITHER the positive or negative terminal
of your battery, and AT THE SAME TIME touch the
tip of your bulb to the OTHER terminal of your
battery.
This will light your bulb - if it does
not light, try tightening the wire around the
collar of the bulb. If you have small hands and a
big battery (like a D cell) you might need the
assistance of another pair of hands to make the
connections tight enough. Try reversing the
terminals - it does not matter which direction you
connect, as long as you have a complete CLOSED
CIRCUIT. But this will work - the battery is
lighting the bulb - the wire just makes a
conducting path. In principle, if you had a long,
skinny, flexible battery you could just touch one
terminal of the battery to the tip of the bulb and
the other to the wire collar, and the bulb would
light up.
Touch one end of the wire to either
terminal of your battery; touch one terminal of
your bulb to the other end of the wire.
Here's a good source on line about how bulbs work:
light bulb
|