When my third graders are studying explorers, we make a ship. We start by using tempera cakes to paint a 9x12 sheet of paper greens and blues. Then we use crayons or oil pastels to color a second sheet in warm colors. The following week, the blue paper is torn and glued to the warm colored paper to make the ocean. The torn parts are white so if they are glued so the white is at the top, it looks like waves. Lastly, the students draw a ship on brown paper and some sails on white paper. The ship is glued to the ocean scene.