1.5 m (4.5 ft) string (Parcel string works best)īefore the demonstration: Mark the plastic cup in the center of the bottom.A wooden ball (~5 cm ) with a hole drilled through it.We will use the simple apparatus shown to demonstrate this third concept, that things closer to the Sun move around it faster than do things farther away. A planet’s orbital period squared is proportional to its average distance from the the Sun cubed.A line from the planet to the sun sweeps out equal areas in equal intervals of time.The orbits of the planets are ellipses with the Sun at one focus.Based on the data gathered by Tycho Brahe, Kepler was able to derive his Three Laws of Orbital Motion: After a protracted legal battle, Kepler returned the instruments, but not the notes.

Unfortunately, Tycho died the year after Kepler arrived, and his family sued to recover both his notes and his instruments from Kepler. He sent copies of his works to Galileo and Tycho Brahe in 1600 CE, Tycho asked Kepler to join him in Prague even though Tycho was a supporter of a modified form of the Ptolemaic theory. He published several books both describing his own work and supporting the work of others (most notably, Galileo). He continued to try various theories to explain the motions of the planets, including numerology and music. (Most, however, did not.) He became an adherent of the Copernican theory of the solar system, and attempted to explain the motions of the planets using the five regular solids (cube, tetrahedron, dodecahedron, icosahedron and octahedron). Though talented in mathematics, he first gained fame as an astrologer when, in 1595 CE, some of his weather predictions came to pass. He attended a pauper’s school and won a scholarship to study religion at the University at Tubingen. Kepler was the eldest child of a poor family.

Keplers laws of planetary motion