Hey, why are those stuffed animals floating around in the pool? Well, because they can. They're floating on little boats made of aluminum foil. Foil is thin, but it holds up the animals just fine. When you float something on a boat, the boat will sink just enough so that the water it "displaces," or pushes out of the way, weighs the same as that object. If something weighs 1 pound, the boat will sink enough to push 1 pound (16 ounces) of water out of the way. If the sides of the boat are too low, the water will gush in over the top! But if the sides are high enough, then the boat floats. So if you want your furry friends to stay dry, just do the math. Weigh them first. Then test your boat with the same weight of pennies or rocks. That way you don't have to have any sinking ships.