Ben Franklin wanted to swim faster. He saw that frogs could swim well. He wondered why. Then he realized that it was because frogs have webbed feet.
Ben had an idea. He invented something like frogs’ feet. They were fins made out of wood. Ben put the fins on his hands. Each fin had a hole for his thumb. Ben swam faster. But his wrists got tired.
Ben Franklin lived many years ago. Today, many people wear swim fins made of plastic or rubber. But now fins go on a person’s feet!