Plot the Dot: A Graphical Approach to Density

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In this activity, learners work in groups to determine the mass and volume of four samples: glass marbles, steel washers or nuts, pieces of pine wood, and pieces of PVC pipe. Learners then plot the data points on a large class graph of mass vs. volume to discover that data points for a particular material form a straight line, the slope of which gives the density of the material.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
45 to 60 minutes

Estimated Materials Cost:
$10 - $20 per group of students

Age Range:
Ages 11 - 18

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • Glass marbles
  • Wood pieces (ordinary pine shelving wood)
  • Steel washers or nuts
  • PVC pieces
  • Plastic bags
  • Balances
  • Graduated cylinders and/or appropriately calibrated beakers or measuring cups
  • Water
  • Large piece of graph paper for plotting graph data
  • Markers
  • Labels - 3/4 in diameter circular labels for four different colors
  • Straightedge
  • Regular graph paper (optional)


  • Mathematics
    • Algebra
    • Data Analysis and Probability
      • Data Analysis
      • Data Collection
      • Data Representation
    • Measurement
      • Units of Measurement
      • Rate
    • Representation
  • The Nature of Technology
    • The Design Process
      • Problem Solving
  • Physical Sciences
    • Structure and Properties of Matter
      • Mass and Weight
      • Volume and Density
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations
      • Communicating Results


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


This resource is part of:

Access Rights:

  • Free access


  • Rathjen, Don


  • All rights reserved, Exploratorium, 2009