Here's a geography homeschool preschool project for ages three to five. My little munchkin is learning about landforms and water. First we made a peninsula, then a harbor, and last an island, using sandbox sand, water, blue and green food coloring and a large foil roasting pan. She added her little animals and had an afternoon of fun. In fact, the next day she wanted to go check out her "beach."
Island -- water all around the land
Peninsula -- a land form partially surrounded by water, but not all the way around it
Harbor -- when the land forms a protective area for the water, for ships to enter safely, less waves, the land makes a "C."