Test your class' understanding of free falling objects with a video demonstration that shows two equal weights dropped simultaneously. One hits the ground first, which is contrary to what students understand about the acceleration due to...

Sal talks about what 'more than' and 'less than' mean using groups of horses. Includes a video, transcript, and question and answer section. [2:02]

The video uses pictures to explain the concept of more than, less than, or the same as.

Zog is introduced to Newton's basic laws of motion. By observing objects on earth and in space, Zog learns that nothing can start moving, speed up, slow down, change direction or stop unless a force is applied to it -- even if the force...

Sal Khan represents division as equal groups of objects. [3:39]