Density Rainbow

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In this activity, learners mix several sugar solutions to investigate the property of density. Each sugar solution has a different density and color of the rainbow. The less dense sugar solutions will be able to float on top of the more dense solutions, and the variation in color will allow learners to create a rainbow inside of a drinking straw. Learners will then consider what items will sink or float, and make inferences about their densities based on the results of their experiments. Includes extensions. Part of the 21-activity guide published by OMSI, No Hassle Messy Science with a Wow. All activities in this guide use household materials and all lesson plans include preparation directions, demonstrations, procedure sheets, cross-curricular connections, and scientific explanation of content.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
30 to 45 minutes

Estimated Materials Cost:
$1 - $5 per group of students

Age Range:
Ages 8 - 14

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

English, Spanish

Materials List (per group of students)

  • cups9-oz. or 12-oz plastic cups 5 per group
  • masking tape 1 roll per group
  • permanent markers (e.g., Sharpie™) 1 per group
  • granulated sugar 1 cup per group
  • teaspoon measure 1 per group
  • clear plastic drinking straws 1 per student
  • pop top bottles 16-oz or larger 2 per group
  • food coloring 4 colors per group
  • access to a sink
  • total of 3–4 gallons of water


  • Physical Sciences
    • Chemistry
      • Solutions
    • Structure and Properties of Matter
      • Atomic Structure
      • Volume and Density
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations
      • Communicating Results

Informal Categories

  • Food and Cooking


To use this activity, learners need to:

  • see
  • see color
  • read
  • touch

Learning styles supported:

  • Involves teamwork and communication skills
  • Involves hands-on or lab activities


Foreign language versions of this resource:

Components that are part of this resource:

Includes alignment to state and/or national standards:

Access Rights:

  • Free access


  • Oregon Museum of Science and Industry


  • All rights reserved, Oregon Museum of Science and Industry, 2007

Funding Sources:

  • National Science Foundation
  • Camille and Henry Dreyfus Foundation