(Adapted from Science Projects in Renewable
Energy & Energy Efficiency written by the
National Renewable Energy Laboratory, published
and copyright 1991 by the American Solar Energy
Society, and distributed by the National Energy
DO NOT ATTEMPT ALONE! YOU'LL
NEED AN ADULT TO ASSIST YOU IN THIS PROJECT!
- Child's pinwheel
- Aluminum foil
- Empty soup can or similar sized tin can with one
end cut off
- A wooden ruler
- Small cooking pot
- Hot plate
- 10p nail
- Tape or rubber bands
- Mitten type of pot holder
Take hammer and nail and carefully punch
a hole in the end of the tin can near the edge. Punch
another whole directly across the top from it. The two
holes should not be bigger than 1/8 inch across.
Tape or attach the ruler to can with rubber bands.
Put water into the pot and cover the top of the pot
with two layers of tin foil. Tightly crimp the tin foil
around the edges so it seals the top tightly.
Using the nail, punch a hole in the top of the
tin foil cover in the very center about 1/16 inch
across. Put covered pot to side.
Put the pot onto the hot plate and bring to a boil.
Put on the mitten pot holder, and when steam starts
coming out of the top, carefully hold the pinwheel over
the one hole. Notice how fast the wheel spins.
Take the can on the ruler and place it
on the top of the pot so that the hole is in the center
of the open end of the can. Steam should now be coming
out of the top of the can through the two holes.
Carefully hold the pinwheel. Turn the pinwheel so that the holes are on opposite sides of the pinwheel. Notice how fast the pinwheel turns.
Take pot off the hot plate and let cool.
Carefully take off the tin foil, add more water to the
pot and put tin foil top back on. Take the nail and poke
lots of holes all over the tin foil. Punch 5 holes close
to the edge away from the center hole, repeat the experiment
with ten holes around the edge, 20 holes around the edge.
Bring the pot back up to boiling. Hold the pinwheel
over only the one center hole. How much steam do you see?
How fast is the pinwheel turning?
With one hole the pinwheel, how fast did the pinwheel
turn? With the can making the steam hit the wheel equally
on either side, what happened? When you punched more
holes in the tin foil what happened?
In a geothermal power plant, steam is used to turn a
turbine. The turbine is attached to a generator to make
electricity. There are two places in the world where
natural steam is found under ground and is used to make
electricity. One is in Italy. The other is north of
San Francisco in an area called The Geysers. The Geysers
produces enough energy to power a city of about one
million people. But in recent years, the amount of steam
produced by the area has decreased. Some people think
that its because there are too many "holes"
in the ground like the pot cover with 20 holes. Its
like having a soda with 20 straws in it and all of your
friends and you sipping at the same time. The soda glass
will be drained VERY fast. Thats what some people
think is happening to the Geysers
running out of steam.