In an AP Physics lab today, we decided to take a break from the humdrum of
problems and have a little fun. I don't know where my teacher learned it
from, but it's nifty stuff.
MATERIALS:
-steel rod; solid, 1/2" diameter, 4' long
-rosin powder; smash up a violin rosin form the orchestra room -he,he
-patience
PROCEDURE:
1. Smash the rosin up to a real fine powder, using a hammer or whatever.
2. Get the palm of your right hand full of the powder.
3. Hold the steel rod exactly at the center with your left hand, using only
your thumb and index finger to balance it upright. Try to keep it tipped a
little downwards in front of you.
4. With your right hand, procede to stroke the rod from a few inches below
your left hand downward to the bottom of the rod, letting your hand slide
right off the end.
5. If you keep stroking in a rythmic pattern, soon you will hear a pure
tone, much like that produced by a tuning fork. The more consistent your
strokes are, the easier it will be to get a tune out, but it takes a little
practice.
This not only gives you quite a workout after a 5 minute trial, but it
allows for _lots_ of experimentation. We used many different length rods
for different frequencies, and this allowed us to play with beat patterns.
Although we haven't tried it yet, we did discuss how to measure the velocity
of the steel, among other topics. You will also find that the amplitude of
the waves is easily increased. We had the entire second floor going *crazy*
with only a half dozen rods singing out in chorus.
--Chris
** :) Christopher M. Maj //=\\ Imajn8r
** :) cmaj@buffnet.net //=\\ ax116@freenet.buffalo.edu
** :) http://www.buffnet.net/~cmaj
** :) "Capital is the fruit of Labor; and thus, it belongs to Labor."
-Abraham Lincoln