This KS3 resource sets out a hands-on science experiment designed to help students understand how microbes spread and multiply.
It introduces key concepts in microbiology through an engaging practical activity that replicates Louis Pasteur’s famous experiment, which disproved the idea of ‘spontaneous generation’.
This resource provides a structured yet flexible practical activity that supports the KS3 science curriculum on microbes and health.
It encourages inquiry-based learning and critical thinking while making microbiology accessible and engaging. It’s ideal for sparking discussions on disease prevention, laboratory techniques and careers in science.
This experiment not only builds practical lab skills but also helps students see the relevance of microbiology in everyday life, from food safety to medicine.
What’s the lesson about?
Students explore the unseen world of microbes by using nutrient broth to grow bacteria. The experiment demonstrates how microbes travel through the air and how different conditions affect bacterial growth.
It reinforces key scientific skills, such as observation, recording results and making predictions.
How does it work?
Students prepare test tubes containing sterile nutrient broth, ensuring it remains uncontaminated until exposed to air.
Some tubes are left open, while others are protected with different barriers (e.g., cotton wool or S-shaped tubes). Over two weeks, students monitor how cloudy the broth becomes – a sign of bacterial growth.
What will students learn?
- How microbes travel through the air and multiply
- The importance of sterile conditions in experiments
- Scientific observation and data recording
- Links to real-world microbiology, such as food hygiene and infection control
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