Make Clay Float: A Change the Shape Experiment

A key across the top shows what floats and sinks look like in a tank. Under the heading Same clay, different shapes, the same lump of modeling clay appears twice: in one panel an arrow turns it into an open boat with a flag; in the other an arrow rolls it into a ball. Under each is a small tank with two dashed rings, and the child colors the ring where that shape ends up, at the surface or on the bottom. The middle strip, headed Same steel, different shapes, shows a nail beside a big steel ship, and the child circles the one that floats. The bottom of the page is one large tank of water where the child draws their own clay boat.

Shape, not material, is the idea. A ball of clay sinks and the same clay pressed into a thin, open boat floats, and a steel ship floats while a steel nail does not. Second graders are ready for this because they have already seen that heavy things can float; now they can make it happen with their own hands. The ship and the nail make the same point on a larger scale, which gives children a way to talk about real boats.

Give each child a small piece of clay and a cup of water before the page. The lump, the boat and the ball are drawn at the same scale, so the page itself shows that the amount of clay stays the same. The big tank at the bottom invites a labeled drawing: where the boat sits, how thin the walls are. Pair it with the true or false face, where the same claims come back as sentences.