The EJSPhases of Moon model displays the appearance of Moon and how it changes depending on the position of Moon relative to Earth and Sun. The main window shows Earth (at the center) and Moon, as well as a circle tracing out Moon's orbit. Sun is far to the right in this picture  and therefore the right side of Earth and Moon are bright while the left sides are dark.  By using the Options Menu the Moon View window shows the appearance of Moon as seen from Earth  when Moon is in the position shown in the main window.  You can modify  this simulation if you have Ejs installed by right-clicking within the plot and selecting  "Open Ejs Model" from the pop-up menu item.  

EJS Phases of Moon model was created using the Easy Java Simulations  (Ejs) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.   Double clicking the ejs_astronomy_MoonPhases.jar file will run the program if  Java is installed.  Ejs is a part of the Open Source Physics Project and is designed  to make it easier to access, modify, and generate computer models.  Additional Ejs  models for astronomy are available.  They can be found by searching ComPADRE for  Open Source Physics, OSP, or Ejs.

Please note that this resource requires at least version 1.5 of Java (JRE).