gravity
Resources
PhET: Kepler's Laws
Interact with the variables to discover how planetary objects moves in elliptical orbits, and the other characteristics of these orbits described by the three Kepler’s Laws. Connect Astronomy with Math, by experimenting with ellipses, areas, and graphs.
PhET: Gravity and Orbits
Move the sun, earth, moon and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it!
PhET: Gravity Force Lab
Visualize the gravitational force that two objects exert on each other. Adjust properties of the objects to see how changing the properties affects the gravitational attraction.
PhET: Gravity Force Lab: Basics
Visualize the gravitational force that two objects exert on each other. Discover the factors that affect gravitational attraction, and determine how adjusting these factors will change the gravitational force.
PhET: Pendulum Lab
Play with one or two pendulums and discover how the period of a simple pendulum depends on the length of the string, the mass of the pendulum bob, the strength of gravity, and the amplitude of the swing. Observe the energy in the system in real-time, and vary the amount of friction. Measure the period using the stopwatch or period timer. Use the pendulum to find the value of g on Planet X. Notice the anharmonic behavior at large amplitude.
PhET: My Solar System
Build your own system of heavenly bodies and watch the gravitational ballet. With this orbit simulator, you can set initial positions, velocities, and masses of 2, 3, or 4 bodies, and then see them orbit each other.