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Downhill Race

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    The Exploratorium

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Downhill Race

In this activity, learners explore how two cylinders that look the same may roll down a ramp at different rates. Learners discover that an object's acceleration rate depends partly on how its mass is distributed. Thus, the cylinder with a heavy hub accelerates more quickly than a cylinder with a heavy rim. Use this activity to introduce learners to potential energy and kinetic energy (specifically, linear and rotational kinetic energy).

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
$1 - $5 per student

Age Range:
Ages 8 - 14

Resource Type:


Materials List (per student)

  • 2 identical round metal cookie tins (such as those from butter cookies)
  • 10 large metal washers (about 1/4 pound [112 g] each)
  • Double-sided foam stick-on tape (or adhesive-backed Velcroâ„¢)
  • A ramp


  • Physical Sciences
    • Energy
      • Potential and Kinetic Energy
    • Motion and Forces
      • Acceleration
      • Rotation Motion
    • Structure and Properties of Matter
      • Mass and Weight
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



  • All Rights Reserved, The Exploratorium,


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