Helpful Microbes and Bread-Making

14th June 2021

This was our introductory activity to get the children to:

  1. Start engaging in inquiry-based science
  2. Appreciate good microbes and understand that most microbes are NOT harmful. (An essential microbiology concept that is particularly important not to neglect in the face of the current pandemic.)
Bread yeast activation
Fermentation experiment using fast-action store-bought yeast. Take a guess: which one received sugar?

Classroom activity:

Basic bread-making ingredients, clear cups and spoons were sent to the school. Microbiologists – China Hanson (Microbiology@UCL Domain Manager) and Praveena Senthilkumar (UCL Biochemical Engineering student) – beamed in via Teams and introduced the activity with a short presentation about helpful microbes in food, yeast, and the process of fermentation. Teachers then gave the children basic instructions for making dough and measuring it rise and then let the children try it in pairs. Children were asked to observe what happened when they added sugar to the yeast vs no sugar and then explain their findings.


The activity turned out great in that it was very interactive and sensory for the children and the overall learning objective was achieved. They seemed to understand very well that yeast used in food are an everyday example of helpful (not harmful) microbes. While they were able to articulate the observation that the yeast grew faster with sugar, they were not so proficient at explaining why. Thus, it wasn’t clear whether most of them grasped the basic chemistry of fermentation, and why the bread was rising. I think some thought that the yeast were visibly/physically getting larger, rather than the rise being a result of the CO2 produced by the yeast.

Additionally, it was the perfect activity for an Early Career Microbiologist or undergrad student as a foray into primary school education and outreach. Praveena did an excellent job creating some simple slides on food microbiology and fermentation and also fielded some really advanced questions from the children! Well done, Praveena!


… Stay tuned for more on this activity from our ECR microbiologist Praveena’s perspective


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