Free-Fall Bottles & Tubes

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In this physics activity, learners conduct two experiments to explore free-falling. In the first experiment, water-filled plastic bottles with holes in them spurt water under normal conditions, but don't leak while in free-fall. In the second experiment, a ping-pong ball in a water-filled plastic tube floats upward under normal conditions, but remains motionless when the tube is dropped or thrown. Educators can use pre-assembled materials for group demonstration purposes. Note: this activity will get the floor wet, so consider doing this outside.

Quick Guide

Preparation Time:
45 to 60 minutes

Learning Time:
45 to 60 minutes

Estimated Materials Cost:
$5 - $10 per group of students

Age Range:
Ages 11 - 18

Resource Types:
Activity, Demonstration


Materials List (per group of students)

  • Electric drill
  • Plastic water or soda bottle
  • Water
  • Table or ladder
  • Large plastic tub
  • Mop and/or paper towels
  • Plastic tube with tight-fitting caps for both ends
  • Hose clamps or duct tape (or epoxy cement)
  • Ping-pong ball (colored)


  • Physical Sciences
    • Motion and Forces
      • Gravity
      • Momentum and Velocity
      • Acceleration
      • Newton's Laws
    • Structure and Properties of Matter
      • Mass and Weight
      • Volume and Density
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Outdoor Activity


To use this activity, learners need to:

  • see
  • be mobile
  • touch

Learning styles supported:

  • Involves teamwork and communication skills
  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access


  • Rathjen, Don


  • All rights reserved, Exploratorium,