Statistics: Wet Heads

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In this math lesson, learners learn how to construct stem and leaf plots. Learners first estimate the number of drops of water that will fit on the head of a penny. Learners write their guesses on Post-it notes and arrange the notes in a stem and leaf plot. Then, learners conduct the experiment and record the results on Post-its that are displayed on the same stem and leaf plot, thus creating a back-to-back stem and leaf plot. Learners work in groups to analyze the data, paying particular attention to the data range and the extent to which different variables may have contributed to any disparities.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
45 to 60 minutes

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

Age Range:
Ages 11 - 14

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


Materials List (per group of students)

  • Post-It Notes
  • Pennies
  • Eye droppers
  • Paper towels
  • Cups of water
  • Markers
  • Activity Sheets
  • Two large sheets of poster board or large space on a clean blackboard


  • Mathematics
    • Data Analysis and Probability
      • Data Analysis
      • Data Collection
      • Data Representation
      • Probability
    • Reasoning and Proof
    • Representation
  • The Nature of Technology
    • The Design Process
      • Problem Solving
  • Physical Sciences
    • Structure and Properties of Matter
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations
      • Gathering Data
      • Formulating Explanations
      • Communicating Results


To use this activity, learners need to:

  • see
  • 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



  • All rights reserved, PBS, 2012

Funding Source:

  • US Department of Education