Springs and Slinkies

Objectives

• Use a model to explain how potential energy transfers to kinetic energy.

Materials

• Per Class or Group:
  Slinkies
  3 or 4 large commercial springs
  several small spings (optional: they can be collected from used pens)
  small weights in regular increments (5 g, 10 g, 15 g, etc.)

Key Questions

• What happens to the potential energy stored in the stretched Slinky when we let go of it?
• If we stretch the Slinky even further, do you think it will spring back faster or slower? Why?
• What happens to the springs when we attach the weights to them? Which spring stretches the furthest?
• Which spring stores the most potential energy?
• Which spring would spring back the fastest if the weight were taken off? Why do you think so?

What To Do

Part 1: Demonstrate, or have students demonstrate, the following with each of the items.

Part 2: Lead your students in a discussion about potential and kinetic energy.

Teacher Tip: Encourage students to ask questions, make predictions, and discover the conclusions themselves.

Slinky:

• Have 2 volunteers hold either end of one Slinky and stretch the Slinky by slowly backing away from one another. Watch what happens when it’s released.

Spring:

• Hold up the springs and observe what happens as you hook the small weights (of varying mass) to each.

Extensions

• Where there any unintended energy conversions? What where they?