For all science teachers and homeschooling Moms and Dads out there, here is a great way to open a science conversation with your kids and get them interested in science and their science homework!

Hey kid…Do you know who is said to have discovered the first telescope? His name is Galileo Galilei or simply Galileo. Aside from developing the first functional telescope, Galileo had many other achievements. He had many science projects on the go, conducted many experiments and developed many scientific theories. This great man had a great mind even though he had many difficulties when he was still alive.



How was Galileo’s early life?

Galileo was born in Pisa, Italy on February 15, 1564. His father was Vinzenzo Galilei, a musician and his mother was Guilia Ammannati. He was the eldest of six children but only three of his siblings survived. He went to the Camaldolese Monastery for his early studies.

How did Galileo become a scientist?

Initially, Galileo studied at the University of Pisa in order to become a physician. However, he was not able to finish his medical degree. Instead, he studied mathematics and fine arts. In 1588, he became an instructor of arts in Florence. During this time, he became good friends with the painter Cigoli, who eventually painted one of Galileo’s scientific observations.

Galileo became the chair of Mathematics at the University of Pisa in 1589. From 1592 to 1610, he served as a professor in the University of Padua, where he taught astronomy, geometry and mechanics. This was the period where he made his great scientific discoveries covering astronomy, applied sciences and mathematics.


What were Galileo’s discoveries?

The following are some of Galileo’s discoveries.

  • The Law of Pendulum: When he was twenty years old, Galileo was in the Cathedral of Pisa and he noticed a lamp swing to and fro. Curious, he wanted to find out how long it would take for each swing to be completed. He observed that the time it took for each swing was the same. This law of pendulum was eventually used to regulate the time shown by clocks.
  • Law of Gravity: According to history, Galileo’s experiment on falling bodies largely contributed to Isaac Newton’s Law of Gravity. In Galileo’s experiment, he is said to have dropped balls from the Leaning Tower of Pisa. The balls were made of the same material but had different masses. Galileo set out to prove that the time it took for these objects to reach the ground would be the same. Galileo proved that objects reached the ground at the same time, independent of their masses.
  • Basic Principle of Relativity: Galileo stated that in any system moving in a straight line, at a constant speed, the laws of physics would be the same. This principle became the basis of the Newtonian laws of motion and Einstein’s special relativity theory.
  • Jupiter’s moons: With the use of his telescope, Galileo was able to see three of Jupiter’s moons. He saw these for the first time on January 7, 1610. These moons or satellites are now known as Io, Europa and Ganymede. Three days later, on January 10, Galileo saw another moon, which was later named Callisto. Galileo named them the “Medicean stars”. Later on, they were named “Galillean satellites” to give credit to Galileo.
  • Heliocentric Theory: The Heliocentric Theory, which was first developed by Nicolaus Copernicus, was the basis of Galileo’s writings. This theory simply means that the Sun is the center of the solar system, and not the Earth. Due to his telescopic observations, Galileo was able to prove that the Earth and the other planets revolved around the Sun, not the other way around.
  • Sunspots: Galileo was also able to observe sunspots, which appear as dark spots on the surface of the Sun and which occur due to magnetic activity.
  • The Milky Way: In his telescopic observations, Galileo was also able to see that the Milky Way actually consisted of many stars, not clouds or nebulae. In his writing entitled “Starry Messenger”, Galileo stated that brighter stars were closer to the Earth and fainter stars were more distant.

Why was Galileo sent to prison?

Because of his work on the Heliocentric Theory, Galileo was put on trial by the Roman Catholic Church in 1633. In his trial, he was said to have committed heresy against the Church, because the Holy Scripture said that the earth was motionless and was the center of the universe. Galileo was required to deny the Heliocentric Theory. He was said to have withdrawn his belief but he was still imprisoned and later on, placed on house arrest. He remained on house arrest until his death.


When was Galileo cleared of the charges of heresy?

In 1882, the Church lifted the ban on Galileo’s book entitled “Dialogue Concerning the Two Chief World Systems”, which contained discussions on Heliocentric Theory. By then, it was already widely known that the Earth has never been at the center of the Universe. In 1992, Galileo was finally cleared of any wrongdoing.

How was Galileo recognized as a scientist?

Albert Einstein called Galileo the “Father of Modern Science” because his discoveries ushered in modern science. Galileo’s contributions were recognized when the first spacecraft launched to Jupiter was named “Galileo spacecraft”. The non-SI unit of acceleration is called “Gal” due to his experiments. In 2009, the International Year of Astronomy, the face of Galileo was printed on a commemorative coin. This coin celebrated the 400th year of the invention of Galileo’s telescope.