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Inverse Square Law

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    The Exploratorium

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Inverse Square Law

In this math activity related to light, learners explore why a light, such as a candle or a streetlight, looks dimmer the farther away from it we get. The answer lies in the Inverse Square Law, which learners demonstrate using graph paper or perfboard. (Two methods are given for this activity.) Learners will discover that the intensity of light is described by the power distributed over an area.

Quick Guide

Learning Time:

Estimated Materials Cost:

Age Range:
Ages 11 - 18

Resource Type:



  • Life Sciences
    • Human Body
      • The Brain and Nervous System
    • Human Senses and Perception
      • Vision
      • Perception
  • Mathematics
    • Algebra
    • Data Analysis and Probability
      • Data Analysis
      • Data Collection
    • Measurement
    • Number and Operations
      • Exponents
    • Problem Solving
  • Physical Sciences
    • Light and Optics
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data


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,

Funding Sources:

  • National Science Foundation
  • California Department of Education
  • NEC Foundation of America


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