Smell the Difference

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In this two-part activity, learners use household items to smell the difference between some stereoisomers, or molecules which are mirror images of one another. First, learners compare the scents of orange peel and lemon peel, which both contain two versions of limonene (a stereoisomer). Then, learners compare the scents of crushed caraway seeds and crushed mint leaves, which each contain a version of carvone (another stereoisomer). Use this activity to help learners discover how a molecule's shape affects smell.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
5 to 10 minutes

Estimated Materials Cost:
$1 - $5 per student

Age Range:
Ages 8 - 18

Resource Type:


Materials List (per student)

  • 1 orange (or orange peel)
  • 1 lemon (or lemon peel)
  • 1 grater
  • 2 small bowls (X 2)
  • caraway seeds
  • mint leaves (fresh or dried)
  • 2 spoons
  • nose


  • Life Sciences
    • Human Body
      • The Brain and Nervous System
    • Human Senses and Perception
      • Smell
  • Physical Sciences
    • Chemistry
      • Chemical Bonding
    • Structure and Properties of Matter
      • Atomic Structure
      • Elements and Periodic Table
      • Elementary Particles and Nuclear Physics
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Food and Cooking


To use this activity, learners need to:

  • smell
  • 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