Further ExplorationNewton's Law of Universal Gravitation
T. Henderson, The Physics Classroom - An excellent tutorial on Newton's theory of gravity, including practice exercises.Newton vs. Einstein vs. the Next Wave
Part of the Gravity: Making Waves bulletin from the American Museum of Natural History.Inverse Square Law
From The Physics Classroom siteDirect Measurement Videos
Direct Measurement videos show situations that viewers can use to learn and apply physics concepts. Grids, rulers, and frame-counters are added as overlays on the video. These allow viewers to make precise measurements of quantities such as position and time.
ClassicsPhilosophiae Naturalis Principia Mathematica
I. Newton - A reproduction of the preface to Newton's famed Principia (1687) and links to the full text.Philosophiae Principia
A photograph of Newton's own copy of the Principia and the fabled apple tree.
News & EventsCavendish Experiment in Top Ten of All Time
The Cavendish Experiment was selected by physicists as one of the ten most beautiful experiments of all time.The Controversy over Newton's Gravitational Constant
From the Eöt-Wash Group at the University of Washington.Measuring the Gravitational Constant
An article from Physics Today about a modern-day experiment to measure the gravitational constant.Current Science News
News from around the world of science.
ResearchMeasuring Gravity on Small Length Scales
S. Smullin et. al., Stanford University - This research group is measuring the force of gravity on very-small-length scales and testing Newton's and Einstein's models of gravitation.Google Scholar
Google - Research database allows searching of the scholarly literature.
B. Willis, Worsley School - A simulation of the effect of gravity on orbiting bodies. Illustrates Kepler's laws on which Newton based his theories.The Cavendish Experiment To Measure the Gravitational Constant, G
Paul A. Heckert, Ph.D. at Decoded ScienceNewtonian Orbit Simulator
Explore the concept of orbits as Newton envisioned them with this Java simulation of Newton's original thought experiment.