Stacy Palen has created 23 videos on key topics to accompany her textbooks, Understanding Our Universe and 21^st Century Astronomy, that instructors can assign as pre-class activities or show in class. A mixture of live demos and mini lectures, these videos explain key concepts in an understandable and compelling way. In the angular momentum video, Stacy stands on the “rotating platform of doom” and is given a small shove with outstretched arms, and then brings those arms in close to her body to demonstrate the conservation of angular momentum. Watch the video below and let us know what types of live demos you do in class!