This simulation allows students to visualize a process of adding two sine waves. Students can see what happens with the resulting wave when they change amplitude and frequency of two initial waves. 

This app helps to understand the waving motion of a string through Newton's laws if you think about a little bit of it, and the force on it at any instant as the imbalance of the tensions tugging at the two ends.

  This applet plots the orbital motion of a spaceship launched from Earth at a given speed. Students need to find the best orbit to Mars by launching at a different speeds and at different times, to meet with Mars as it moves around its orbit. 

A clock bouncing light between two mirrors is animated, to show vividly why taking the speed of light the same in all inertial frames leads inevitably to time dilation.    

Newton's imaginary cannon is on a high mountain, and fires a cannonball above the atmosphere. This simulation illustrates that the motion of an cannonball near the Earth and the circling motion of the Moon around the Earth are different aspects of the same thing.

This applet describes a single atom gas moving in one dimension. It accelerates or decelerates only through classical collisions with the moving piston on its container. This helps to explain why the gas gets warm when it is compressed and cool when expanded.

Projectile motion is a form of motion in which an object or particle i.e. called a projectile is thrown near the Earth's surface, and it moves along a curved path under the action of gravity only. The simulation visualizes this motion and helps to understand this phenomemon. 

This applet shows how atomic velocities cause the Brownian Motion of a dust particle. In one panel a small ball jitters. In the next, we see that it jitters because many smaller balls bat it rapidly about.