In 1608, Galileo showed that cannon balls, arrows and projectiles traveled on a parabolic path. The path of any object through space is a parabola.
Mechanical Devices
Galileo took much interest in mechanical devices. He proposed ideas of machines transforming energy rather than creating energy. In 1594 he created a pump that raised water using only a single horse.
Astronomy
During 1604 he became more fascinated about astronomy and started lectures on a star that had appeared that year. In 1609, during Galileo remodelled the current telescopes at the time, which only had a magnification of 3x. His versions of the telescope had a magnifications of 20x – 30x and allowed him to view the moon, satellites of Jupiter, the milk way, sunspots and the phases of Venus. Galileo’s efforts and findings in astronomy had made him famous and was appointed as court mathematician of Florence.
As Galileo discovered more and more about the solar system, he learnt that the planets including earth revolved around the sun. He proved that the Copernican theory was correct. This caused a great upset in the Catholic Church, which controlled society. The Catholic Church had a strong belief in the Aristotelian Universe. They opposed Galileo and refused to accept his findings, they wouldn’t even look through his telescope, as they believed it was possessed by demons that could make anything appear.
Galileo was accused of heresy and faced the Inquisition. He was forced to publicly admit his findings were incorrect. However, that did not stop him from printing his book, “Dialogue Concerning the Two Chief World Systems”, which contained supporting evidence and propositions for the Copernican theory. In 1633, Galileo was sent to Rome to be trailed again by the Inquisition and was found guilty of Heresy. He was sentenced to house arrest for the remainder of his life and died in 1642 outside Florence in his home.
Galileo’s greatest contribution to Physics
Aristotle stated that objects at rest stay at rest unless a force is acted upon them, but objects in motion do not remain in motion unless a force is acted constantly on them. Galileo held many experiments and found that Aristotle was mistaken, as it did not include the hidden force, which was the friction between the surface and object.
One of the experiments Galileo performed was pushing a block of wood across a table with oil. From this he learnt that frictional forces could be reduced, if a frictional force was to be reduced to exactly zero, an object pushed on a frictionless surface would remain at that speed forever unless another force acts upon it later on.
Galileo’s concept of inertia states:
“An object in a state of motion possesses an ‘inertia’ that causes it to remain in that state of motion unless an external force acts on it”
This concept will become Newton’s first law of motion.
Thus, Aristotle held that objects at rest remained at rest unless a force acted on them, but that objects in motion did not remain in motion unless a force acted constantly on them. Galileo, by virtue of a series of experiments (many with objects sliding down inclined planes), realized that the analysis of Aristotle was incorrect because it failed to account properly for a hidden force: the frictional force between the surface and the object.
