Using a milk carton or yogurt tub, you can make a device that gives you a fish’s eye view of the underwater world.
Cut away both ends of the milk carton or the bottom of the yogurt tub (the container should be open on both ends). Then cover one end with a generous piece of plastic wrap so that it comes far up on all sides. Secure with a rubber band and cover that with duct tape to prevent water from seeping through. Done!