Getting electricity to do something: electrical current and simple circuits
Unfortunately, we can't see what is happening
inside a wire.
However, we can develop a
conceptual language that will let us understand how electricity
works,
if we imagine that there is an "electrical fluid"
that moves through the wires.
Let's familiarize ourselves with some electrical components:
A D-cell battery has two ends (and sides, which don't do
anything). A battery is like a pump: it tries to push "the
electrical fluid" out one end. By convention, the direction of flow
is from the positive end (the top of the battery -- the end with
the bump on it) to the negative end (the bottom).
Many electrical components, like the motor in your kit, come
with two wires already attached. One lets the current get to the
device, and the other carries it away again. When we connect the
two wires to the two ends of the battery, something is likely to
happen.
Some electrical components, like the light bulb in your kit,
have no labels at all, and it isn't even clear where wires are
supposed to be attached to it to make it go. We will figure this
out shortly.
Time to explore! Here are some things to think about and do. Do these explorations. Record in your
journal about what you learned, and any questions or problems you
encountered. We will ask to see your journals at the end of
the workshop.
Make the motor run.
Figure out how to use the battery holder and the wires with the
"alligator clips" on them to have the motor run by itself.
Light the light bulb! (This will probably need more than two hands). The light bulb contains a very thin (the
filament) that gets really hot when the current runs through
it. For this to happen, there needs to be a way for the current to
get from one end of the battery to one end of the filament, and a
way for the current to continue from the other end of the filament
to the other end of the battery. But where are the places to
connect to the two ends of the little wire? That's for you to
figure out. Need a
hint?
Make a "cut away" drawing showing your prediction of what is inside a
light bulb, and shows how it might be connected together.
Do these explorations. Record in your
journal about what you learned, and any questions or problems you
encountered. We will ask to see your journals at the end of
the workshop.