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.

Please note that this resource requires Java Applet Plug-in.