Why Are Two Eyes Better Than One?

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In this activity, learners explore how their depth perception would be affected if they only had one eye. Learners work in pairs and attempt to drop a penny in a cup with one eye covered. Learners will discover that with practice they can improve their one-eyed depth perception. This activity works well as as a quick introduction activity or demonstration about sight and stereoscopic vision. [Activity is publicly available through a web crawler capture on Archive.org.]

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
5 to 10 minutes

Estimated Materials Cost:
free per student

Age Range:
Ages 6 - 18

Resource Types:
Activity, Demonstration, Experiment/Lab Activity


Materials List (per student)

  • a cup
  • a penny


  • Life Sciences
    • Human Body
      • The Brain and Nervous System
    • Human Senses and Perception
      • Vision
      • Perception
  • 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, Ontario Science Centre, 2011