In this lesson you will determine how the mass of an object affects its movement toward Earth. As an object falls freely, its speed increases. This change in speed is called acceleration. The experiment shows balls made of various substances being dropped 50 cm. By measuring the position of each object at each video frame during its fall, you will be able to compare the behavior of various objects. Each object has a different mass because they do not have the same density. By comparing the falls of the objects, you will determine how mass changes the way an object falls.