Show students the following videos and discuss the reason for the results in terms of inertia. Emphasize that there are the two aspects of inertia. 1) a body at rest remains at rest, and 2) a body in motion remains in motion in a straight line — Unless/until a force is applied to start it moving or stop it from moving.
Physics Lab Activity/Inertia – YouTube
Have kids give and discuss examples of how we see and use inertia in numerous actions of everyday life. (see text)