What's Next? Here's a simple experiment to test different shapes and their abilities to hold weight as they float. Cut several 12-inch x 12-inch squares of aluminum foil. Fold the squares into a variety of differently shaped containers. Some might have flat bottoms, while others are rounded. The sides can be taller, shorter, steeper, or flatter. Add pennies to each container until it sinks. Which containers carried the weight, and which ones didn't?