Why Do Humans Like to Get High? – YouTube

“We’ve told you before that there really isn’t any evidence that animals consume mind-altering substances because they feel good to them. This makes it appear that the fondness for psychoactive drugs is, pretty…human. What is it about our species that makes us so attracted to these substances?”

Hosted by: Hank Green

How do pregnancy tests work?

Over-the-counter pregnancy tests give potentially life-changing results with a pretty high rate of accuracy. But how do they work? Tien Nguyen explains how each test performs a scientifically rigorous, multi-stage experiment that goes from start to finish in the time that it’ll take you to watch this video.

Lesson by Tien Nguyen, animation by Andrew Foerster.