Science · Stage 6

Helpful and Harmful Microbes

Some microbes make us ill or spoil our food — but many are useful, making bread, yoghurt and healthy soil. Learn to tell helpful from harmful.

✦ Science📘 Stage 6 · S6⏱ ~10 min🧒 Ages 10–12★ Free to start

I can give examples of microorganisms that are helpful and ones that are harmful.

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Kavi Meets the Tiny Ones

Kavi peers down a microscope and gasps 🔬. "Microbes are living things far too small to see — bacteria, viruses and fungi like yeast and mould. Some are harmful: they give us diseases like colds and food poisoning, or they make food rot and decay. But many are helpful! Yeast makes bread rise, friendly bacteria turn milk into yoghurt, and microbes break down waste into rich soil. The same tiny world holds our friends AND our foes — let's learn to tell them apart!"

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What your child will learn

1A friend or a foe?Every microbe falls into one of two groups for us. Tap each card to hear it.

2Microbes at workMicrobes are busy all around us. Tap each one — is it helpful or harmful?

3Helpful or harmful?Drop each microbe into the right box: is it doing a useful job (helpful) or causing harm (harmful)?

4Friend or foe?Read each one and predict helpful or harmful. Tap to check! Tap Next test for more.

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A peek inside

Yeast is stirred into bread dough and the loaf puffs up big and soft. 🍞 Is yeast a helpful or a harmful microbe here, and how do you know?

Yeast is a tiny fungus. As it feeds on the sugar in the dough it gives off bubbles of carbon dioxide gas, and those bubbles make the bread rise. It is doing something useful for us, so it is helpful.

Try this at home: Name one helpful microbe and say what it does.

Ready to play and learn?

Start the free interactive lesson, or print the handout for screen-free play.

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Part of Science · Stage 6 · S6 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.