The soda can tab is more than meets the eye. In its resting state, the tab is what engineers call a "second-class" lever: the force you apply only moves one way, like a wheelbarrow. When you ...

Best of all, this device is fully portable—the size of a soda can—so you can bring it anywhere, and you don't even have to plug it in. The built-in battery runs for up to two hours ...