Fermenting Yogurt

In this lab, students observe the process of fermentation by making their own kefir yogurt. They begin by considering how fermentation has been used throughout human history to make delicious foods, and how fermented foods continue to play an important role in diets around the world. They then design and conduct an experiment to determine how changing a variable, such as temperature or milk type, changes the characteristics of yogurt. Kefir is used as the starter culture to introduce microorganisms into milk to make yogurt. After collecting observational and pH data over a 48-hour period, students organize their findings into a recommendation to a food biotech company looking to develop a new kefir yogurt product.

 Learning Objectives

  • Design and conduct an investigation to determine how a particular variable affects kefir yogurt fermentation.
  • Explain the role of microorganisms in the process of fermentation.

 Prior Knowledge

  • Experience with measuring liquids using graduated cylinders
  • Foundational understanding of experimental design

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Disciplinary Core Ideas:

LS1.C – Organization for Matter and Energy Flow in Organisms
“As matter and energy flow through different organizational levels of living systems, chemical elements are recombined in different ways to form different products. ”

Science and Engineering Practices:

Conducting Investigations

Crosscutting Concepts

Cause and Effect

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Paradise Valley HS
Phoenix, AZ

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Burton HS
San Francisco, CA

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Lincoln HS
San Francisco, CA

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Burlingame HS
Burlingame, CA

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Marianne Gudmundsson
Glenbrook South HS
Glenview, IL

Well organized and scaffolded; flexible structure and can be used partially or as a whole. This unit can be used as is...superbly written and thought out...incorporates many skills and allows student collaboration and student choice/voice.

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South San Francisco HS
South San Francisco, CA

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Capuchino HS
San Bruno, CA

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