Melts in Your Bag, Not in Your Hand

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In this activity, learners use chocolate to explore how the Sun transfers heat to the Earth through radiation. Learners compare the melting rate between chocolate left in the sunshine and chocolate left in the shade outside for twenty minutes on a hot sunny day. Use this demonstration to introduce learners to solar radiation as well as the importance of summer safety and sun protection. Although this works best on a hot sunny day, this activity can be adapted for indoor use.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
1 cent - $1 per group of students

Age Range:
Ages 6 - 14

Resource Types:
Activity, Demonstration, Experiment/Lab Activity, Lesson/Lesson Plan


Materials List (per group of students)

  • Two (2) small pieces of chocolate
  • Two (2) small resealable snack bags
  • Marker to label bags


  • Earth and Space Science
    • Earth Processes
      • Weather and Climate
    • Solar System
      • The Sun
  • Life Sciences
    • Human Body
      • Muscles and Skin
      • Health and Nutrition
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
      • Heat Transfer
    • Energy
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Formulating Explanations

Informal Categories

  • Food and Cooking
  • Nature and Environment
  • Outdoor Activity


To use this activity, learners need to:

  • see
  • be mobile
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



  • All rights reserved, National Weather Service,