## Lesson Plan

Physics on the Playground

Sliding, climbing, swinging—playgrounds are a great place to observe physical forces, such as gravity, momentum, and friction.

- Grades: 3–5

Invite students outdoors to take a closer look at the science behind the fun with these hands-on activities. Encourage them to predict, observe, and draw conclusions along the way. Then, once they are familiar with the concepts of simple forces, challenge them to prove what they learned using the Playground Physics **Reproducible**, below. Ask students to circle at least four of the kids on the page who are being pulled down by gravity. (Some students may circle all the people in the playground you might discuss the concept that all the people are affected by gravity, while some are actually in the process of being pulled down.?) You might also challenge them to identify areas where other forces such as momentum and friction may be present. Finally, encourage students to finish the story using glossary words from this unit.

**Swinging Forces**

**Slip Sliding Away: Friction Comparison**

** **

**Air Resistance Test**

TRY THIS: Tell students that a bowling ball and a feather will fall at the same speed — if nothing is in the way of their fall. What could get in their way? Invisible air! Next, hold up two identical pieces of paper, and crumple one into a ball. Ask students to predict which one will fall faster. Then have student pairs investigate by each student dropping a piece of paper — one flat and one crumpled — at the same time from a high place on the playground. Ask students: If the pieces weigh the same, why does one fall faster? Air resistance! More air pushes back against the flat piece, slowing its fall.

**Stronger Than Gravity**

**Seesaw Lever Lift**

TRY THIS: For this two-part activity, you´ll need a heavy object that students can safely lift — such as a big dictionary — and a seesaw, which will act as a lever. First, ask pairs of students to predict which will require more force: lifting the object up into the air with their hands, or lifting it by using a lever (placing it on the lowered end of a seesaw and pushing on the other end). Have pairs test their predictions. They should discover that using a lever to raise an object requires less force than directly lifting does. Next, challenge students to test, and then answer, why it matters where you sit on the seesaw. What happens if you sit close to the center?

**Body Balancing**

TRY THIS: Ask students to form pairs and observe one another from the side as each tries to lean forward, with straight legs, and touch the ground in front of his or her toes. Ask them to observe how the body changes to stay in balance — when one part moves forward, another part leans back. Then ask for predictions: What would happen if you tried to touch your toes with your heels pressed against the wall? Have students try it against the wall of the school. Is it impossible? Explain that one´s body can´t move its center of mass too far to one side without losing balance. What if two students leaned against each other? Can students identify where the pair´s center of gravity is?

**The Best Ride Ever**

- Subjects:Science

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