Mr. Andersen illustrates and explains how all objects contain positive and negative charge. [5:24]

In this video we hack apart a bread board to create a 5 volt power distribution strip. The 5 volts comes from the center pin in the motor controller and the negative or ground comes from the ground pin on the motor controller. [5:23]

This video segment adapted from A Science Odyssey takes a look at the scale of the atom and the tremendous amount of space between the electrons and the nucleus. If all this empty space exists in matter, how can any substance be solid?...

An example of simplifying a seemingly complicated resistor circuit. [9:44]

See a worked example of question 2ab: 2015 AP Physics 1 free response.