Galileo Galilei

The Italian scientist and scholar Galileo Galilei made a series of pioneering observations that laid the foundation for modern physics and astronomy . He was an important Italian astronomer, mathematician, physicist, philosopher and professor who made different pioneering observations of nature with lasting implications that were very important for the study of physics . He was also the first to build a telescope and faithfully supported the Copernican theory , which supports a solar system that was centered on the sun . Galileo was twice accused of heresy for the church because of his beliefs, and wrote several books on his ideas.

Personal information:

  • When was he born:  02/15/1564
  • Where he was born:  Pisa, Italy
  • When he died:  01/08/1642
  • Where he died:  Arcetri, Italy

Who was Galileo Galilei?

Galileo Galilei was a scientist recognized as the most important representative of Newtonian mechanics, an astronomer, a mathematician and a physicist who based his studies on a telescope.

Biography of Galileo Galilei:

Galileo was born on February 15, 1564 in Pisa, Italy and died on January 8, 1642, in Arcetri , a town near Florence. Philosopher , astronomer, and mathematician who made fundamental contributions to the sciences of motion , astronomy , and the strength of fundamental materials for the proper development of the scientific method . He was the eldest son of Vincenzo Galilei , a musician that he made important contributions to the theory and practice of music and that he may have carried out some experiments together with his son Galileo on the relationship between pitch and string tension.

In his adolescence , Galileo attended the school of the monastery at Vallombrosa , near Florence, and then in 1581 enrolled at the University of Pisa , where he went to study medicine . However, mathematics attracted his attention more so he decided to make mathematical subjects and philosophy his profession, against his father.

In 1585, Galileo decided to leave his studies without having obtained a degree, and for several years he gave private mathematics classes in Florence and Siena . His reputation increased when he gave two lectures at the Florentine Academy , on the disposition of the world in Dante’s Inferno . He also found some theorems about the centers of gravity that brought him recognition among mathematicians.

He managed to obtain the chair of mathematics at the University of Pisa in the year 1589.

Galileo Galilei’s father:

From his father he inherited a love for music and its intellectual and spiritual foundation . He was originally from Florence and his family was illustrious in his time. He was a great concert performer , music theorist and connoisseur of languages , in addition to having extensive mathematical knowledge . He interfered in the life of Galileo Galilei, when he thought of becoming a priest, convincing him otherwise because he was sure that his son had other different talents, so he sent him to study medicine. He explored, together with Galileo, experimentation and measurementto prevent knowledge from becoming theoretical disquisitions. Galileo helped his father find a balance between theories and experiences of sound . Thanks to them, the union that occurred between music and science helped solve problems related to acoustics , they formulated mathematical formulas to determine the vibration and length of the different strings . The scientific thought for which Galileo advocated was important for Vicenzo, and in turn, the theory mHis music along with his instruments gave Galileo a way to experiment with physical hypotheses.


Among his main discoveries, we can say that Galileo Galilei was the first man who managed to discover that the universe we inhabit is neither fixed nor immutable . He claimed that the universe was changeable through his observations based on disappearing stars and new stars being born in the universe. Also he found as Venus and Mercury are moving around the sun and how the sun could turn on its own axis.

Inventions of Galileo Galilei:

  • The Pendulum: He discovered that the oscillations produced by the pendulum regardless of the magnitude of the oscillation or the weight of the lead, the ball always needed the same time to complete one oscillation. The only thing that produced some kind of effect over time was the length of the thread from which the ball hung .
  • The balance hydrostatic : It  was an instrument to measure the strength of momentum that fluids exert on the bodies when they were submerged . It was based on Archimedes’ principle and is used to measure densities of solids and liquids.
  • The Water Thermometer: It was a glass tube whose end was a closed sphere. The open end is dipped upside down in alcohol and water , and the sphere is on top. When the liquid was heated it rose through the tube and in this way the temperature of the tube could be measured.
  • The Telescope : He made the first telescope and used it to view the moon , jupiter, and the stars . Thanks to this telescope, Galileo made great discoveries in astronomy. One of the most important was made on January 7, 1610, the day he was able to observe four of Jupiter’s moons revolving around this planet. He was also able to build a microscope which could increase the size of the observed object by up to 30 times.


Galileo Galilei promulgated several physical and chemical laws, some of them are:

  • The rate of fall of a body is independent of the mass of the object.
  • The speed of the fall of a body is independent of its nature .
  • The speed acquired by a given body that falls freely after being at rest is proportional to time .
  • The pendulum had a perfect swing and divided the time into small fragments
  • All bodies fall at the same speed .

Scientific method:

His scientific method was called ” scientific resolution-compositional method .” He used it to make different hypotheses and draw conclusions . The steps of this method were as follows:

  • Observation
  • Elaboration of an explanatory hypothesis
  • Deduction
  • Experiment or verification

Contributions of Galileo Galilei:

Galileo Galilei proved that the model of the universe was wrong by separating the Catholic Church from science . He managed to understand that bodies accelerated at the same time regardless of size or mass, and that movements occurred through the force that was applied. He managed to improve the telescope and adjust the lenses that made it up. He observed the satellites of Jupiter . He contributed to the study of sunspots thereby reinforcing Copernicus’ theory.


  • The sidereal messenger.
  • The operations of the geometric and military compass.
  • The book of speech about things that float on water.
  • Dialogues on the two greatest systems in the world.
  • Two new sciences.

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