Density Intensity

Source Institutions

Source Institutions

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In this activity on page 12 of the PDF (Rethinking the 3 R’s: It’s Easy to be Green), learners examine how recyclable materials are separated by various properties at recycling centers. Learners determine the density of various objects as well as if the materials are magnetic. Use this activity to discuss the properties of matter and the importance of recycling.
Safety notes: Follow Milli's safety tips on page 13 and do this activity with an adult.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
45 to 60 minutes

Estimated Materials Cost:
$5 - $10 per student

Age Range:
Ages 8 - 14

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per student)

  • Polyethylene Terephthalate (Resin ID code 1) — such as plastic water bottles, soda bottles
  • High-Density Polyethylene (Resin ID code 2) — such as milk jugs, detergent bottles
  • Low-Density Polyethylene (Resin ID code 4) — such as six-pack rings
  • Polypropylene (Resin ID code 5) — such as bottle caps, drinking straws, yogurt containers
  • Polystyrene (Resin ID code 6) — such as disposable coffee cups
  • Measuring spoons
  • One marble
  • One paper clip
  • Water
  • Sodium chloride (table salt)
  • Magnet
  • Isopropyl rubbing alcohol 70%
  • Light corn syrup
  • 3 small clear bowls or containers
  • Two plates
  • Tongs
  • Tape
  • Marker


  • Engineering and Technology
    • Engineering
      • Chemical Engineering
  • Physical Sciences
    • Electricity and Magnetism
      • Electromagnetic Fields
    • Chemistry
    • Motion and Forces
      • Gravity
    • States of Matter
      • Solids
    • 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
  • The Nature of Technology
    • Technology and Society
      • Technology and the Environment

Informal Categories

  • Nature and Environment


To use this activity, learners need to:

  • see
  • read
  • touch

Learning styles supported:

  • Uses STEM to solve real-world problems
  • Involves hands-on or lab activities


Foreign language versions of this resource:

Access Rights:

  • Free access


  • Golden, Melissa ; Harnden, Gregory ; Dougherty, Ryan


  • All rights reserved, American Chemical Society, 2012