This interactive simulation helps students visualize the gravitational force that two objects exert on each other. It features two spherical objects exerting a gravitational pull on each other.  The mass of either sphere can be changed from 1-100 kg. Watch the force vectors change as you change the mass. The simulation was designed to promote two basic concepts: 1) All interacting objects exert a gravitational pull, even if it is very small; 2) The magnitude of the gravitational attraction depends on the mass of the interacting objects and their distance apart.  

Editor's Note: Scroll down on the page to find supplementary lesson plans and activities, such as a Calculations Lab, Clicker questions, and quantitative graph building.

This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET). The simulations are animated, interactive, and game-like environments in which students learn through exploration. All of the simulations are freely available from the PhET web site for incorporation into classes.