In the Toilet

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This activity explores the basic workings of a siphon, which is the core technology that makes toilets work. The heart of the lesson plan is a simple demonstration of a siphon and how it works: use a hose to move water between two buckets on two different levels. The lesson plan suggests several extension activities including giving learners cups, tubing and water, and inviting them to experiment with different siphon arrangements to see how water behaves. The lesson also has information about the physics of siphons, including a comparison of siphons (which work based on gravity) and drinking straws (which work based on air pressure differences). [Activity is publicly available through a web crawler capture on]

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 8 - 14

Resource Types:
Activity, Demonstration, Lesson/Lesson Plan, Simulation


Materials List (per group of students)

  • 2 buckets
  • 3 feet of tubing, preferably clear tubing (aquarium tubing or garden hose works)
  • water
  • OPTIONAL: empty soda bottle
  • OPTIONAL: rubber stopper (size 3 or 4) with 1 hole, and 1 foot of tubing that fits the hole (often 3/16” diameter). (Available from Flinn Scientific: 1-800-452-1261)
  • OPTIONAL: pipe with 4 holes in it
  • OPTIONAL: transparent glasses
  • OPTIONAL: small lengths of tubing


  • Engineering and Technology
    • Engineering
      • Civil Engineering
  • Physical Sciences
    • Motion and Forces
      • Gravity
    • States of Matter
      • Liquids
  • The Nature of Technology
    • Technology and Society
      • Technology and History


To use this activity, learners need to:

  • see

Learning styles supported:

  • Involves hands-on or lab activities


Includes alignment to state and/or national standards:

Access Rights:

  • Free access



Funding Source:

  • National Science Foundation ESI, 0206403