Newton's 2nd Law

In this video, the students are demonstrating Newton's 2nd Law, which states that acceleration is directly proportional to force and acceleration is inversely proportional to mass. The larger marble is rolling down the ruler and hitting the smaller marble. Because the larger marble has more mass, it creates a greater force on the smaller marble. A greater force means that the marbles will have a greater acceleration (since acceleration is directly proportional to force). However, when the smaller marble is rolling down the ramp, it creates a smaller force. Since the smaller marble as a smaller mass, the force it hits the larger marble with will be decreasingly different from the force the large marble hit the small marble. Thus the acceleration will be slower when the smaller marble hits the larger marble. The difference between the two marble's acceleration is because of their difference in mass which creates a difference in their forces.