What Happens Beside the Climbing Dome?

An Oak, a Squirrel, and a Playground

From a rest bench beside the playground's climbing dome, Anika's class watches a mature oak beyond the fence. A gray squirrel climbs its trunk and carries an acorn to the ground. The children stay on the playground. They use photographs, school planting records, and labeled models to investigate structures they cannot see from the bench.

The oak has spreading roots, rough bark, and broad leaves. Roots take in water from the soil. Inside the roots, trunk, and branches, narrow tubes carry water toward the leaves. Leaves use light to make food for the plant. A groundskeeper's photograph shows a scrape in the bark that did not reach the wood underneath. The bark forms an outer covering over living tissues.

The class examines enlarged photographs of acorns. A hard outer coat surrounds a tiny young oak and stored food. In a school planting record, a shoot emerged from an acorn before its first leaves unfolded. As the shoot grew, the stored food became smaller. Another acorn, whose young plant had been eaten, did not sprout. Acorns are seeds produced by oak trees.

A close-up photograph shows the squirrel's curved claws catching rough places in the bark. Its hind legs push against the trunk as it climbs. A labeled body model shows muscles inside the legs attached to bones. When these muscles shorten, they pull the bones. The model also shows lungs inside the chest. Lungs bring oxygen from the air into the body; working muscles use oxygen.

To explore grip safely, the class compares a rounded plastic hook with a smooth plastic tab. Each shape is attached to the same small wooden cube in turn. Students press it against the same upright piece of rough cloth, release it, and count whether the cube stays in place for five seconds. They run ten trials with each shape.