Because leaves come in a variety of shapes and colors, they can help you teach preschoolers about sorting. Take children outside to collect their own leaves. Encourage them to collect as many different types and shapes as they can find. Inside, ask children to sort their leaves. Have them first sort leaves into groups based on color, then have them arrange leaves based on shape or texture. For instance, children might make a piles of leaves that are pointy versus curved, or bumpy versus smooth.
Have children paint the undersides of leaves with different colors of paint. Show them how to use only a thin layer of paint so the detail of the leaf veins will show up in the finished artwork. Help children press the leaves onto paper like stamps. Encourage each child to create a pattern of leaf prints. She might create a pattern of alternating colors or leaf shapes. Have children exchange papers. Ask each child to say what print should come next in the pattern.
Children can save and study leaves forever once they've been pressed. Let each child choose four or five favorite leaves. Give each child two pieces of contact paper. Help children remove the paper backing from one piece, then lay it on the table with the sticky side up. Ask children to arrange their leaves on the paper so they fit without any edges sticking out. Cover the leaves with a second piece of contact paper. Punch two holes in the top of the contact paper and tie on a ribbon or yarn handle. Hang the pressings in a window.
Use the unique shape and design of leaves to teach preschoolers about fossils. Give each child a lump of clay or play dough and a few leaves. Have children roll out their clay, then let them experiment with pressing the leaves into the clay with the vein sides down. When children gently pull the leaves off, they should see the imprint on the clay. Explain that soft substances such as clay take on the shape of harder substances, such as rock or even dinosaur bones. Let the clay harden for a few days, then let children paint their imprints.