Levers use mechanical advantage to ease lifting; they consist of a bar and a pivot (fulcrum) with effort, fulcrum, and load arranged differently in first, second, and third class levers ...

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 lift ...

Your index finger is now the fulcrum of a first-class lever. Pull down with the other hand and… pop! Congratulations. You've just opened a bottle with a newspaper!