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KS2: Useful Microbes

Students will learn that not all microbes are harmful by examining when microbes are useful to humans. A yeast racing competition is used to demonstrate to students that microbes can be beneficial.

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Learning objectives
All students will:
  • Understand that some microbes can help keep us healthy
  • Understand that some microbes can be put to good use
  • Know that microbes grow at different rates depending on their environments
Background Information

Microbes can be both useful and harmful. One of the main ways in which microbes are beneficial is in the food industry. Cheese, bread, yoghurt, chocolate, vinegar, and alcohol are all produced through the growth of microbes.

The microbes used to make these products cause a chemical change known as fermentation – a process by which the microbes break down the complex sugars into simple compounds like carbon dioxide and alcohol.

This lesson plan will introduce the concept of useful microbes by looking at how fungi makes bread dough rise and identify other microbes that are used to make other food products.

Main activity:
  • Yeast races
Main Activity video
Extension activities:
  • Fill in the blanks
Curriculum links


  • Health and prevention


  • Working scientifically


  • Reading and comprehension
Supporting Materials
Teacher sheets
KS2 Useful microbes teacher guidance
KS2 Yeast races - video transcript
Student worksheets
SW1 Yeast races
SW2 Fill in the blanks
Student handouts
SH1 Yeast races handout