Checking For Starch

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In this chemistry activity (page 3 of the PDF), learners will observe a chemical change, specifically what happens to iodine when it is applied to ripe and unripe apples. From the reaction of iodine to the fruit, learners will infer that as fruit ripens, the starch which is present in unripe fruit changes to something else (sugar). Though this activity is included as a pre-visit activity for a workshop about physical and chemical changes, it also is an excellent stand-alone activity.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
Over $20 per group of students

Age Range:
Ages 8 - 14

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • 1 potato for demonstration purposes
  • ripe apples – at least one slice per learner
  • unripe apples – at least one slice per learner
  • 1 plastic pipette (per learner)
  • 1 small artist's brush (per learner)
  • 1 small paper plate (per learner)
  • 1 golf pencil (per learner)
  • 1 bin or tote (per group)
  • 1 bottle of iodine in non-spill bottle (per group)
  • wet wipes (per group)


  • Physical Sciences
    • Chemistry
      • Chemical Reactions
      • Chemistry of Life

Informal Categories

  • Food and Cooking


To use this activity, learners need to:

  • see
  • see color
  • taste
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Includes alignment to state and/or national standards:

This resource is part of:

Access Rights:

  • Free access