1. Sir Isaac Newton (December 25 th, 1642-1727) 1665 23 years old Newton’s Mountain

2. Newton’s Second Law Exerted on the moon by the Earth Exerted on the Earth by the moon

3. Newton’s Inverse Square Law of Gravitation The gravitational field strength twice as far from the source is spread over four times the area, hence one-fourth the strength!

4. Vertical section drawing of Cavendish's torsion balance instrument including the building in which it was housed. The large balls were hung from a frame so they could be rotated into position next to the small balls by a pulley from outside. Figure 1 of Cavendish's paper Henry Cavendish (1731 – 1810)

6. Law of Universal Gravitation Where r = distance from center to center

7. Newton’s Shell Theorem – A uniform spherical shell of matter attracts a particle that is outside the shell as if all the shell’s mass were concentrated at its center.