# Galileo Galilei

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Galileo Galilei (1564-1642), who was considered the father of modern science, made many important contributions to the fields of physics, astronomy, cosmology, mathematics and philosophy. Galileo was the first scientist to try “experimental scientific method” and was also the first to use a refracting telescope to make major astronomical discoveries. He discovered a number of scientific insight that paved the way for future scientists like Isaac Newton.

In 1583, Galileo made his first important discovery, describing the rules that determine the motion of pendulums. In his life, accurate timekeeping was virtually impossible and non-existent. Despite that, Galileo observed that the steady motion of a pendulum could improve this. In 1602, he calculated that the time it takes a pendulum to swing back and forth does not depend on the arc of the swing. Moreover, near the end of his lifetime, Galileo designed the first pendulum clock. Many ideas of clocks these days are still being based on his idea of the pendulum.

Galileo’s idea was that the period of a pendulum is defined as the time (in seconds) that the pendulum takes to complete one full oscillation . The theory was that for a small oscillation the period, T, of a pendulum is given by:

The length of the pendulum, l, is defined as the distance between the centre of mass of the bob and the pivot point. g is the acceleration due to gravity.

To test this idea, I designed a lab experiment (similar to Galileo’s original experiment).

Pendulum Lab

Equipment:

A 50cm long pendulum (bob and string)

Metre Ruler

Rigid support and stand

Stopwatch

Safety:

Loose things not hanging out

Goggles and lab coat

Procedure:

Fix the length of the pendulum at 20cm.

Draw the pendulum back such that the string makes a small angle to the vertical. Then release the bob.

Start timing when the bob has past through the lowest position a few times.

Stop timing when the bob has made 20 oscillations.

Record the time.

Repeat the experiment for the pendulum at 20cm 3 times.

Repeat the experiment for the different lengths of the pendulum.

My Conclusion:

In Conclusion, my value for acceleration due to gravity was an overestimate. Human error may have been a factor that caused this because the timer could not be stopped at the exact point when the bob passed the lowest point for the 20th time.

The Ancient Greek scientist, Aristotle, thought that heavier objects fall faster then lighter ones, a belief that still held in Galileo’s lifetime. But Galileo did not believe this. Being the first person to use “experimental scientific method”, Galileo experimented with balls of different sizes