About

If you were a lifeguard at the beach and you saw a struggling swimmer in the water, it would be your objective to reach the swimmer in the least amount of time. But since you can run faster on the sand than you can swim in the water, you can't run directly at the swimmer. You can reduce your time by running a longer distance on the sand and swimming a shorter distance in the water. Your path to the swimmer will be a bent path - bent at the point where you transition from running to swimming. In this Interactive, learners will determine the entry point into the water that results in the least time. Then their analysis of the data will relate principle of least time to Snell's law of refraction. Now go save that swimmer ... in the least amount of time.