Experiences

Celestial mechanics: a new science dealing with an old theme

Paola Falsini

Italy

High Secondary School

Physics, Science

Laboratory, Online Learning, Extracurricular activity

Direct, Indirect

Even though students are often interested in astrophysics, they have little knowledge of celestial mechanics. How can students value the impact of the Copernican Revolution, if they are not acquainted with the characteristics of the geocentric model?
This project started during the summer holiday between the ninth and the tenth grade. Students were asked to observe the night sky with the help of a quadrant (created by themselves) at different times throughout several weeks. They had to report the results on a chart.
What students observed was the celestial sphere (and consequently the sun) moving around the earth. Back to school, students’ observations were re-enforced with the help of simulation software.
In this way they realized how reasonable could be the geocentric representation of the universe: in the Aristotelian theory these observations supported the idea that Earth was the center of gravity of the Universe. The simulation software highlighted the irregular orbit of the planets that only the heliocentric theory could explain. Ptolemy strongly objected to the idea that the earth could move: if the earth rotates around its own axis then everything else should rotate from the east towards the west. Students held the same misconception! At the same time they were puzzled, because they knew that the earth revolves around the sun.
Students were then asked to read from The Dialogue Concerning the Two Chief World Systems, where Galileo objected to the arguments raised by traditional philosophers with the theory of the indelible motion.
The aim of this project was to make students aware that the astronomical revolution meant a new idea of physics.
The principle of relativity is crucial when studying motion and Newton’s laws of motion.