Perhaps the most common type of motion with constant acceleration is the free fall of unsuspended objects to the earth. Our everyday experience of this phenomenon is strongly affected by the fact that we live in a dense gas which is our atmosphere. The atmosphere exerts a drag force on objects as they fall the magnitude of which is shape dependent and does not scale with the mass of the object. It is this force which leads to the very different free fall for the dime and the feather within this glass tube. To examine what a free fall looks like without the drag force we remove the air from the tube using this pump. (pump out the tube). In vacuum the dime and the feather fall together. Although Galileo could not produce a vacuum he reached the same conclusion through his famous inclined track experiments. In fact we don't need a vacuum to examine the free fall without drag, just an experiment designed so that the effect of the drag force from the atmosphere is irrelevantly small.