"Galileo was that guy who
invented the telescope." This is what most people say when
they think about Galileo. However, Galileo did not even
invent the telescope; he only made improvements to it so it
could be used for astronomy. Galileo did use it to make
many important discoveries about astronomy, though; many
of these discoveries helped to prove that the sun was the
center of the galaxy. Galileo also made many important
contributions to Physics; he discovered that the path of a
projectile was a parabola, that objects do not fall with
speeds proportional to their weight, and much more. For
these discoveries, Galileo is often referred to as the founder
of modern experimental science. Galileo Galilei was born in
Pisa, Italy on February 15, 1564. Until he was about 10
years old, Galileo lived in Pisa; in 1574 the family moved to
Florence where Galileo started his education at
Vallombroso, a nearby monastery. In 1581, Galileo went to
the University of Pisa to study medicine, the field his father
wanted him to peruse. While at the University of Pisa,
Galileo discovered his interest in Physics and Mathematics;
he switched his major from medicine to mathematics. In
1585, he decided to leave the university without a degree to
pursue a job as a teacher. He spend four years looking for a
job; during this time, he tutored privately and wrote on some
discoveries that he had made. In 1589, Galileo was given the
job of professor of Mathematics at the University of Pisa.
His contract was not renewed in 1592, but received another
job at the University of Padua as the chair of Mathematics;
his main duties were to teach Geometry and Astrology.
Galileo taught at the university for eighteen years. Galileo
made many important discoveries from the time he was born
to when he left the University of Padua, 1564-1610. While
attending the University of Pisa, 1584, Galileo discovered
the principle of isochronism. Isochronism showed that the
period of a pendulum remains the same no matter what the
amplitude is. Galileo was said to have discovered this while
watching a chandelier swing in the cathedral next to the
Leaning Tower of Pisa. Galileo proved the isochronism of a
pendulum in 1602. He later used his discovery to design a
clock that used pendulums. While Galileo was looking for a
job after he left the University of Pisa, 1856, he invented the
hydrostatic balance. This was a device that found the
specific gravity of substances by weighing them under water.
This is what gave Galileo his first notice from the public.
Galileo also discovered that Aristotle\'s belief that objects fall
at velocities proportional to their weight was wrong. He
found that all objects fall at the same rate; it is only the
density of the median they fall through that causes larger
objects to fall slower. He believed that all objects would fall
the same rate if they were in a vacuum. It is said Galileo
showed his students at the University of Pisa his discovery
by dropping a musket ball and a cannon ball at the same
time from the Leaning Tower of Pisa. Some scientists in an
article in New Scientist claim that Galileo was wrong in
saying that all objects fall at the same rate. They base their
calculations on the quantum theory. Particles in the objects
are constantly absorbing and releasing photons; this
absorbing and releasing changes the total energy that the
particles carry, which depends on temperature. This then
changes the inertial mass of the object. From this the
scientists concluded that heavier and cooler objects will fall
faster than those objects that are lighter and hotter. Although
this disproves what Galileo found, Galileo was still fairly
correct in his findings; the effect these scientists found is very
small. It is almost impossible to measure the difference in the
time it takes two objects of different weights to reach the
ground. ("Galileo Got it Wrong", p. 36.) Galileo also made
many discoveries while he was teaching at the University of
Padua. Some of his little inventions were a calculating
compass, a thermometer, and a pump. One of his bigger
discoveries was that the path of a projectile was a parabola.
The parabola was due to the combined forces of horizontal
motion and vertical acceleration. He tested this by mounting
a chute on a table and letting the ball on it fly off the edge.
He then marked the spot where the ball landed. This became
very useful in the firing of ballisticas, guns, and rockets.
Another discovery Galileo made while he was at the
University of Padua was the "law of fall," 1604. Galileo
explained the "law of fall" as "the spaces passed over