The Physics class was investigating the relationship between mass speed, and centripetal acceleration (the force that is required to maintain circular motion). Spinning the cup first with 150 ml (grams) of water in a horizontal circle, measuring the radius (which increases as the force on the rubber bands increases), and then with 300 ml (grams) of water. Students recorded the time for 10 revolutions and the radius of the spinning cup and used that data to calculate the tangential speed and period. They will then use that data to calculate the centripetal force exerted on the cup. And no one got wet!