Note: This is the secondpost in a weekly video series on basic microeconomics.

To demonstrate how much of a good or service people are willing to buy at different prices, economists often use a graph called the demand curve.

In this video, Marginal Revolution University revealswhat a demand curve is, explains “why people go crazy on Black Friday,” and shows how people respond to changes in the price of oil.

(If you find the pace of the videos too slow, I’d mend watching them at 1.5 to 2 times the speed. You can adjust the speed at which the video plays by clicking on “Settings” (the gear symbol) and changing “Speed” from normal to 1.25, 1.5 or 2.)

Previous in series:What Christians should know about (basic) economics