"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