Overview: Today on Daily Planet, we shake some bridges to see how they fare during earthquakes! We also show you a mouth guard designed to monitor a player in real-time and detect concussions. And since it's Groundhog Day, we have a special guest in the studio. It's Clover the groundhog! Also on tonight: Alan Nursall lunges marshmallows at people in the name of science, and Dan checks out the smallest bats you've ever seen! Tonight, only on Daily Planet!