Answer 1:
I suggest you first look at some designs.
Wikipedia is a good place to start -
it is not the only place to look, but it can
help. See
geothermanl-electricity
There is a good schematic here:
alternative-
energy
But...then I found exactly what I think
you're supposed to be doing here:
science-
projects
Scroll down the page a bit, and you'll find
this description of how to do your
experiment:
Geothermal Energy Part 1: Setup
Have a student simulate a geothermal energy
plant where scientists gather
energy from the Earth's heat. Fill a kitchen pot
halfway with water. Place
two layers of aluminum foil on the pot so that
steam cannot escape. Punch
a 1/8-inch-wide hole through both layers of foil
in the center of the
pot. Take an opened aluminum can, such as an old
green bean can, and place
it with the opening face down. Punch a 1/8-inch-
wide hole on one side
using a hammer and nail. Punch an identical hole
on the opposite side.
Place a ruler on the side of the can, flush with
the bottom, and attach it
using a rubber band. Heat the pot of water to
boiling over medium heat.
Make a dot with a permanent marker on the back
of a pinwheel, placing the
dot at the outside edge so that rotations can be
counted.
Geothermal Energy Part 2: The Experiment
Heat from the Earth naturally rises to the
surface.
When the pot of water is boiling, place
the aluminum can on the foiled pot
over the hole. Hold the pinwheel above the can
and measure its rotations
for 20 seconds. Do this three times for 20
seconds each. Make a mark on
the ruler at the height where the pinwheel is
held. Take the can off the
ruler, hold the ruler on the top of the pot, and
place the pinwheel at the
same height as before. Measure the rotations for
20 seconds, record your
findings and repeat two more times. Take the pot
off the heat, allow it to
cool and refill the pot with water so that it is
half full. Replace the
aluminum foil layers and punch eight holes 1/8th
of an inch through both
layers of foil around the edges of the pot.
Repeat the experiment and
analyze the results.
First of all, if this is the experiment
you're supposed to do, I'd say DRAW A
PICTURE OF IT FIRST so you can visualize what
you're supposed to do.
Second, I'd ask: Why in part 1 do they say to
poke 1 hole in the foil, and in
part 2 they say to punch 8 holes in the
aluminum? Why 2 holes in the can, on
opposite sides? Why not just one hole on one
side?
To answer your question as to how many
graphs, well...a lot. Let's think it
through:
What are the variables in this experiment?
2. Height of pinwheel
3. Number of holes in the can
4. Number of holes in the foil
You might also say that the mass of the pinwheel
is a variable. What would be
the difference, do you think, of a lighter or
heavier pinwheel? One that has
more mass towards the center, or more towards
the outside? I would say, look
up some pictures on the internet to see what
design geothermal engineers have
used. Then select your pinwheel design.
Next, why do you think they say to fill the
pot half full? What could be the
advantage of using more or less water? You might
just decide that you are not
going to vary the amount of water. I'd state
that in the introduction to my
write up...
For height of pinwheel: I'd say, first get a
feeling for how height of
pinwheel affects the rotations. Blow a stream of
air out your mouth at the
pinwheel, and move it up and down, so that your
air stream hits the edge to
the center. The place on the wheel where the
stream of steam hits may affect
the speed - that is, hit closer to the end of a
blade vs. hitting closer to
the center.
This is called torque: if you push on a wheel
closer to the edge, you have
more leverage, because you have more distance to
the center of the rotation.
Try this - if you want to open a door, do you
have to use more force if you
push closer to the hinge, or closer to the
outside? So, for the same force,
would the door open faster if you push closer to
the hinge or the outside?
I would say that you want to start by having
the steam hit the pinwheel at the
edge of the blade, then move the pinwheel up (or
down) in half-inch increments
until the steam is hitting it in the center. You
don't have to test any more
heights, because the other side is just the
mirror image of the first side, so
you would expect the same results as you go out
towards the other edge.
Last, number of holes. They want you to start
with 1 hole in the foil and 2
holes in the can. I'd start with 1 hole in the
foil and 1 hole in the can.
Then increase the number of holes in the foil
while keeping only 1 hole in the
can. Then I'd punch a second hole in the can,
take new foil, and do the whole
thing again - starting with 1 hole in the foil,
and increasing to 8.
So, how many graphs?
Let's say, water level is fixed at half. You'll
have to check and make sure
the level is constant, so you'll have to add
water and get it back up to a
boil in between changing the other variables.
Note from ScienceLine coordinator:
Please go to the next field (Answer 2) to
read the rest of this answer | 
