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Re: free fall data



Phil,
The article on Galileo's inclined plane was by Stillman Drake, an
outgrowth of his book "Galileo at Work" in which he reproduced many of the
experiments from Galileo's notebooks. He didn't use Galileo's original song
but "On ward Christian Solders" for its nice 4/4 beat. Drake found with this
timing method, if you were good you could time things within a 1/32 of a
second and even people with poor timing could set things within 1/8 second.
The great irony of this series of experiments is that it ends with one where
Galileo puts a lip at the bottom of his incline so that the ball is moving
horizontally and predicts where it will hit the floor when it goes off the
table. Here the notebook ends his experiments on inclined planes. Because of
the rolling motion of the ball we know it did not fall where he expected! So
he went on to build the telescope.
Daniel's bring up the Florence Museum of Science is a really neat
Web site. It is layout just like the museum itself, and you can click on the
objects in any of its cases. Beside its Galileo collection, it has some
interesting 18th century electrostatic apparatus and telescopes. But the
inclined plane dates from the turn of the nineteenth century not Galileo's
time.
The finger on the other hand is the real thing.



Gary Karshner

St. Mary's University
San Antonio, Texas
KARSHNER@STMARYTX.EDU