Teacher sheet · Ages 6–7 · about 45–50 minutes
Tiny living things
Lesson page: echoesof.science/school/microbes/ages-6-7/ · Pupil worksheet: echoesof.science/school/microbes/ages-6-7/print/
Learning aims
- Know that microbes are tiny living things that are almost everywhere.
- Name bacteria, viruses and fungi.
- Know that some microbes are useful and some can be harmful.
- Observe that yeast gives off a gas and works better when warm.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: show a slice of bread. Who helped make it? (A microbe!) |
| 10 min | Read the text together; look at pictures of microbe shapes. |
| 15 min | Set up the yeast balloons; check them later in the lesson. |
| 5 min | Game: Helpful or harmful? |
| 5 min | Quiz and worksheet. |
Materials for the experiment
- Two small clean plastic bottles
- Two balloons
- A packet of dried baker's yeast
- Sugar
- Warm (not hot) tap water and cold tap water
- A funnel and a teaspoon
Safety: Use warm tap water only, never hot or boiling water. Do not taste the mixture. Wash hands after the experiment. Anyone with a latex allergy uses latex-free balloons or watches. Pour the mixture down the sink at the end.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| All microbes are bad germs. | Most microbes are harmless or useful; only a small number make people ill. |
| Microbes are only on dirty things. | Microbes are found almost everywhere, even on clean things, and some help keep us healthy. |
| Yeast is just a powder, not alive. | Dried yeast is made of living cells that become active with water, sugar and warmth. |
Worksheet answers
- Any drawing; a round, rod or spiral shape for a bacterium is fine.
- Bread, yoghurt, cheese or vinegar.
- The warm one.
- Soap and water help wash harmful microbes off our hands so they do not spread.
Quiz answers
- What is a microbe? A tiny living thing. Microbes are living things too small to see.[1]
- Can you see a microbe with your eyes alone? No, they are too small. You need a microscope to see most microbes.[1]
- Which of these is a group of microbes? Bacteria. Bacteria, viruses and fungi are the three big groups.[1]
- What does yeast do to bread dough? Makes it rise. Yeast gives off a gas that makes the dough rise.[2]
- What helps stop harmful microbes spreading? Washing hands with soap. Handwashing with soap is one of the best ways.[2]
Going further
Put a third bottle with yeast and warm water but no sugar. Does its balloon grow? What does this tell you about what yeast needs?
Sources used in this lesson
- [1] KS1: Introduction to Microbes (e-Bug, UK Health Security Agency): reliability High
- [2] KS2: Useful Microbes (e-Bug, UK Health Security Agency): reliability High
- [3] What is microbiology? (Microbiology Society (UK)): reliability High
- [5] Microbiology: Types of microorganisms (Encyclopaedia Britannica): reliability Medium-high
- [8] About Handwashing (Centers for Disease Control and Prevention (USA)): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/microbes/sources/
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