Michelle Obama We're encouraging our girls to start early with exercise. You know ... their dog and then they're running around, because kids can't sit still. So they're not going to just sit ...

This video, suitable for older kids, including teens and tweens ... how and why popcorn kernels pop like they do, how fitness trackers track your movements, and how a 3D printer shapes items ...

It can be. I mean, just like adults, if kids don't have a fun way to get active, it is just a dreaded chore, especially if they don't feel like an athlete. But exercise is so important for helping ...