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The Shadow Knows I

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The Shadow Knows I

In this activity, learners will measure the length of their shadow from the Sun and compare it three to four months later. This process will help learners investigate Earth's rotation and discover the change in seasons by the elevation of the Sun. This resource includes an explanation of why learners will observe changes in their shadow's length as well as a description of Eratosthenes' first known measurement of the circumference of the earth. Learners can measure the circumference of the Earth using shadows in the related activity "The Shadow Knows II." This resource also includes winter and summer safety tips.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
1 to 12 months

Estimated Materials Cost:

Age Range:
Ages 6 - 14

Resource Types:
Activity, Lesson/Lesson Plan


Materials List (per group of students)

  • Yard/meter stick or tape measure
  • Sheet to log measurements


  • Earth and Space Science
    • Earth Processes
      • Weather and Climate
    • Earth Structure
      • Earth, Moon and Sun
    • Earth, Moon and Sun
      • Days
      • Seasons
    • Solar System
      • The Sun
      • The Moon
  • Mathematics
    • Data Analysis and Probability
      • Data Analysis
      • Data Collection
    • Geometry
      • Solid Geometry
    • Measurement
      • Size and Scale
      • Circles
  • Physical Sciences
    • Light and Optics
      • Reflection and Refraction
      • Sunlight and Color
    • Motion and Forces
      • Rotation Motion
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations

Informal Categories

  • Nature and Environment
  • Outdoor Activity


To use this activity, learners need to:

  • see
  • read
  • be mobile
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access



  • All Rights Reserved, National Weather Service,


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