Ship Shape

Density isn't the only property that affects whether something floats or not. If you drop an iron nail into water, it will sink. But a huge ocean liner made of steel (which is mostly iron) floats. How can that be? And what experiment can you do to figure out what shapes float?

Well, you could heat the iron very hot then pound it into different shapes, but there must be an easier (and safer) way! You can use clay (but not Play-Doh) instead. Roll some clay into a ball, then drop it into a bowl or bucket partly filled with water. What happens? Now flatten the clay and fold up the sides to make a little boat. Does this float?

Once you have a boat design that floats well, try filling it with "cargo", like marbles or paper clips. How much can it hold before it sinks? Experiment with other designs, and see which one holds the most cargo.