The C++ Project (free edition)

This software implements a few elementary simulations of classical physics. It has multi-ball collisions and gravitational simulations, like a planet and its satellite, and a simplified satellite launching.

In the simulation "Fifty balls; Weightless (gas simulation approach). Piston under gravity.", it is possible to study the concepts of force and energy. The user can increase the energy of the system in real time (through heat, using the '→' and '←' keys). Thus, you can check the rise, on average, of the potential energy of the piston (work done by the system). In this way, the program can illustrate the First Law of Thermodynamics, approximately.

An example of gravitational simulation is the "A Fictional Universe" simulation. Sometimes it is possible to watch the formation of objects representing approximately a planet and its satellite.

It was made in C++ language, so to be able to make as fast and powerful simulations as possible.

This is the free version, but we have a paid version (with a free trial period) that is programmable (you can set the variables).