Every fact in the three microbes lessons is listed here with where it comes from. The numbers in [brackets] on the lesson pages link to this list.
Wikipedia was not used as a source. Numbers are rounded (for example 9.8 m/s² for Earth's gravity). The text was drafted with help from AI (Claude) and then checked against these sources. Corrections: hello@echoesof.science.
Simplifications and care points: the lessons use three main groups (bacteria, viruses and fungi) as school schemes do; scientists also count archaea, protozoa and algae as microbes. Whether viruses are 'alive' is debated, because they cannot reproduce without a host cell; we say they are microbes but not cells. 'Too small to see' is true for most microbes, but some large bacteria and moulds can be seen. The doubling time of about 20 minutes is for E. coli in ideal laboratory conditions; real growth slows when food runs out. The yeast experiments use baker's yeast only: pupils never try to grow bacteria or moulds from their hands or the room in open dishes. Questions about illness or medicines go to a parent, the school nurse or a doctor.
Type: Government health education programme for schools
Microbes are tiny living things too small to be seen with the naked eye. The lesson covers three groups: viruses, bacteria and fungi. Microbes are found almost everywhere on Earth; some are useful and others can be harmful to humans; they come in different shapes and sizes.
Used in: Ages 10–11 (text); Ages 6–7 (quiz); Ages 6–7 (text)
Type: Government health education programme for schools
Cheese, bread, yoghurt, chocolate, vinegar and alcohol are all produced through the growth of microbes, by fermentation that breaks sugars into simpler compounds such as carbon dioxide and alcohol. Looks at how yeast makes bread dough rise. Some microbes help keep us healthy; microbes grow at different rates depending on their environment.
Used in: Ages 10–11 (experiment); Ages 10–11 (quiz); Ages 10–11 (text); Ages 15–16 (experiment); Ages 15–16 (text); Ages 6–7 (experiment); Ages 6–7 (quiz); Ages 6–7 (text)
Type: Professional scientific society
Microbes are organisms too small to see without magnification; groups include bacteria, archaea, fungi, protozoa, algae and viruses. Most viruses are up to 100 times smaller than the average bacterium. Microbes are the oldest life form on Earth, with fossil microbial communities about 3.48 billion years old in Australia. Disease-causing microbes are called pathogens and make up less than 1% of microbial species.
Used in: Ages 10–11 (quiz); Ages 10–11 (text); Ages 6–7 (text)
https://microbiologysociety.org/why-microbiology-matters/what-is-microbiology.html
Type: Professional scientific society article
'Microbe' includes bacteria, archaea, fungi, protozoa and viruses. Viruses depend on host cells to reproduce, and scientists question whether they are alive. Not all microbes are microscopic: some bacteria and bread mould can be seen with the naked eye. Antibiotics target bacterial infections and do not work against viral ones.
Used in: Ages 10–11 (text); Ages 15–16 (text)
https://asm.org/articles/2021/april/what-counts-as-a-microbe
Type: Edited encyclopaedia
All bacteria are prokaryotic: single-celled organisms without a membrane-bound nucleus. Bacteria have shapes including spheres, rods and spirals; cells are generally 0.5 to 5 micrometres wide. Fungi are eukaryotes with rigid cell walls and no chlorophyll; moulds are multicellular and filamentous, yeasts are single-celled and ferment carbohydrates, producing alcohol and carbon dioxide, as in bread.
Used in: Ages 10–11 (experiment); Ages 10–11 (quiz); Ages 10–11 (text); Ages 15–16 (experiment); Ages 15–16 (quiz); Ages 15–16 (text); Ages 6–7 (experiment); Ages 6–7 (text)
https://www.britannica.com/science/microbiology/Types-of-microorganisms
Type: Peer-reviewed open textbook
Viruses are acellular (not made of cells) and must infect a host cell to reproduce: they are obligate intracellular parasites. A virus has DNA or RNA (never both) inside a protein coat called a capsid; some have a lipid envelope. Typical virions are about 20 nm to 900 nm, too small for a light microscope; electron microscopes are used to see them.
Used in: Ages 10–11 (quiz); Ages 10–11 (text); Ages 15–16 (quiz); Ages 15–16 (text)
Type: Peer-reviewed open textbook
Bacteria most commonly reproduce by binary fission. The generation (doubling) time is the time for the population to double; E. coli can double in as little as 20 minutes in optimal laboratory conditions. N = N0 × 2^n gives the number of cells after n generations. A growth curve has lag, log (exponential), stationary and death phases.
Used in: Ages 15–16 (experiment); Ages 15–16 (quiz); Ages 15–16 (text)
https://openstax.org/books/microbiology/pages/9-1-how-microbes-grow
Type: National public health agency
Washing hands can keep you healthy and prevent the spread of respiratory and diarrhoeal infections. Germs spread when people touch their eyes, nose and mouth with unwashed hands, prepare food with unwashed hands, touch dirty surfaces, or cough or sneeze into their hands. Steps: wet, lather, scrub for at least 20 seconds, rinse, dry.
Used in: Ages 6–7 (text)
Type: National health service
Many infections are caused by viruses, so antibiotics are not effective against them. Overuse has made antibiotics less effective and led to 'superbugs', bacteria resistant to many antibiotics, such as MRSA; health organisations are trying to reduce antibiotic use, especially for problems that are not serious.
Used in: Ages 10–11 (quiz); Ages 10–11 (text); Ages 15–16 (quiz); Ages 15–16 (text)
https://www.nhs.uk/medicines/antibiotics/antibiotic-antimicrobial-resistance/