The Concepts: Children will use their sense of smell to sniff cross sections of evergreen trees. You can use donated Christmas trees, with trunks cut into 1- to 2-inch sections, or you can buy the tree blocks online. Students will put things in order from smallest to largest, use a hand lens to get a closer look at the rings of the trees, and use a tape measure to determine the distance across tree blocks and the height of their structures. The concept of recycling can also be introduced in this lesson.

Check out the video for this activity here.