I Istituto comprensivo “Fabrizio de André”

The Science: Galileo Galilei

Galileo Galilei“Galileo, perhaps more than any other single

person, was responsible for the birth of modern science.”

-Stephen Hawking

Galileo’s Life..

-Galileo Galilei was born in Pisa, Italy on February 15, 1564

-Oldest of seven children

-His father wanted his son to study medicine because there was more money in medicine.

-At the age of eleven, Galileo was sent off to study in a Jesuit monastery.

Education

-After four years, Galileo told his father that he wanted to be a monk.

-This was not exactly what father had in mind, so Galileo withdrew from the monastery.

-In 1581, at the age of 17, he gave into his father’s wishes and entered the University of Pisa to study medicine, as his father wished.

-By 1585 he gave up his courses in medicine and left without a degree to become a mathematics teacher.

His love for maths.

-Galileo began teaching maths privately in Florence.-Public appointments.

-Books and sharing his thoughts.

Galileo's Observations

-Galileo was one among the first scientists who questioned the ancient ideas and disproved them.

-The discovery of isochronism

-Two objects with different weights fall down at the same speed

Galileo’s Inventions

-Reasons for Inventing

-1593: Thermometer

-1597: Compass

-1609: Telescope

-1641: Pendulum Clock

-Galileo invented a telescope that had 3x the magnification then Hans Lippersney Invented in 1608.

-With this telescope he could see magnified, upright images of earth.

-First to report lunar mountains and craters, made the conclusion that the moon is rough and uneven just like Earth.

-Also he observed Venus, Milky way, and Saturn.

Galileo’s astronomical observations

He observed that Jupiter had four satellites with revolving periods of about 2 to 17 days.

He proved then that Earth is not the only center of motion in the universe.

Galileo’s astronomical observations

He found that Venus goes through phases just like the moon.

This disproves the Ptolemaic system wherein Venus will only have a 45 degree elongation and will only show a crescent phase according to geocenric model.

Nothing New….?-Showing Planets were disks, not points of light

-The great “cloud” the Milky way was composed of enormous numbers of stars that had not been shown before.

-Planet Saturn had “ears” the rings of Saturn but his telescope wasn’t good enough to show them as more than extensions on either side of the planet.

-Showing moon was not smooth.

Galileo’s astronomical observations

He discovered that the surface of the moon is uneven, rough, full of cavities and prominences that contradicts the long held belief that heavenly bodies are perfect, smooth and incorruptible.

He hypothesized that dark areas on the moon are marias or seas.

Galileo’s astronomical observations

He observed blemishes on the Sun that we know as sun spots.

Sun spots are large, comparatively cool areas on the Sun that appear dark because of their contrast with the brighter and hotter solar surface.

Galileo observed that spots would move day and after some time disappear, and about two weeks same spots would reappear.

Galileo’s astronomical observations

According to Galileo sunspots could be located either on the surface of the Sun or very close to it.

And that these sun spots are carried around by its rotation.

He also estimated that Sun’s rotation is a little under a month.

Galileo’s Experiments in Mechanics

Galileo greatest contributions were in the field of mechanics.

Mechanics is the study of motion and the actions of forces on bodies.

He conceptualized that falling bodies of different mass would hit the ground at the same time but on Earth the event described could be affected by resistence.

Galileo discovered laws that invariably described the behavior of physical objects.

The most far reaching is the law of inertia. Inertia of a body is that property of the

body that resists any change of motion. If a body is at rest, it tends to remain at

rest. Some outside influence is requiered to

start it in motion

Galileo’s Experiments in Mechanics

Galileo’s Experiments in Mechanics

Rest was regarded as the natural state of matter.

But Galileo showed that motion is as natural as rest.

He reasoned that if an object is slid on a material that is frictionless it would continue to slide on.

Friction is the resistance encountered by an object moving relative to another object with which it is in contact.

Galileo’s Experiments in Mechanics

He also thought that force is required to

1. Slow down2. Stop3. Speed up4. Or change the direction of a moving

object.

Galileo’s Experiments in Mechanics

Galileo also studied the way bodies accelerate.

There is acceleration when bodies change their speed as they fall freely or roll down inclined planes.

Galileo’s Experiments in Mechanics

He found that bodies accelerate uniformly.

That is to say,in equal intervals of time,they gain equal increments in speed.

Galileo formulated these in precise mathematical terms

Church Controversy

-It is commonly believed that the Catholic Church persecuted Galileo for abandoning the geocentric (earth-at-the-center) view of the solar system for the heliocentric (sun-at-the-center) view.

-He was sentenced to imprisonment, but that was later condemned to house arrest.

-During this period, personal interpretation was a sensitive subject. In the early 1600s, the Church had just been through the Reformation experience, and one of the chief quarrels with Protestants was over individual interpretation of the Bible.

Galileo Galilei

February 15, 1564 - January 8, 1642