In this activity learners build water-propelled engines from soft drink cans. Water flowing out of holes in the can cause the can to rotate in the direction opposite to the stream, explained by Newton’s Third Law of motion. Learners can vary the size, angle, number, and placement of holes they make in each can. This engine simulates the original engine built by Hero of Alexandria thousands of years ago, though Hero’s engine used steam instead of water flowing from the container. The instructions include background information, worksheets, and an extension to build a model of Hero’s original engine. The behavior can be compared to how a rocket engine works.