View full lesson: http://ed.ted.com/lessons/how-do-pregnancy-tests-work-tien-nguyen

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.