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Sour Power

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    Discovery Education

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Sour Power

In this weeklong activity, learners explore how the growth of additional bacteria after pasteurization is slowed in colder temperatures. Learners discover how non-refigerated milk sours and how the bacteria produce lactic acid, which causes the milk to curdle.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
1 to 7 days

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

Age Range:
Ages 6 - 11

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • two clear plastic cups per group
  • pasteurized milk
  • refrigerator


  • Life Sciences
    • Cells
      • Cell Metabolism
    • Diversity of Life
      • Viruses and Bacteria
    • Human Body
      • Health and Nutrition
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
  • 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
  • smell
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



  • All Rights Reserved, Discovery Education, ©2012


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