Viruses
100 nm
From nanometres to colonies — how size, time and numbers change what a microbe can do.
Magnitude duel
Pick two teaching marks from the scale atlas. Compare their order-of-magnitude sizes — literacy, not taxonomy.
Marks are typical classroom orders, not measured species ranges.
Classroom scale worksheet
Write one observation beside each teaching mark, then print.
Marks are order-of-magnitude teaching sizes, not species ranges and not a lab protocol. Not for medical or laboratory use.
Classroom scale sheet
Pin two teaching marks already on this scale, write one line, print, and reopen the same sheet.
Order-of-magnitude teaching sizes — not species ranges, not a lab protocol, not diagnosis.
Larger mark vs smaller mark — count the zeros, do not name a species.
Protozoa
40 µm
Literacy checks
Open a claim, then read the teaching note from that topic. Not diagnosis or treatment.
Educational only. If you are ill, contact a clinician — these cards cannot triage you.
Claim Influenza — The flu shot gives you the flu.
Literacy note Inactivated shots cannot replicate. Live nasal sprays are weakened and unused in many programmes.
Claim Norovirus — Only cruise passengers get norovirus.
Literacy note Schools, hospitals and homes see far more cases. Ships are amplifiers.
Claim Escherichia coli — All E. coli makes you sick.
Literacy note Most strains are gut residents. Pathotypes are a minority with extra tools.
Claim Probiotics — Any yoghurt is a proven probiotic.
Literacy note Only products with live, identified strains and evidence meet the usual definition.
Claim Antibiotic resistance — The patient becomes immune to antibiotics.
Literacy note The microbe changes or is replaced by a resistant strain. The person's immune system is a different story.
Claim Viruses — Viruses are just tiny bacteria.
Literacy note Bacteria are cells with ribosomes. Viruses are not cells and do not grow on agar as colonies.
Claim Bacteria — All bacteria make you sick.
Literacy note Pathogens are a minority. Many species are neutral or helpful on barriers.
Claim Fungi — Fungi are plants that lost chlorophyll.
Literacy note They are a separate kingdom closer to animals, with chitin walls and external digestion.
How to read the scale
Size and time change what a microbe can do — read nanometres before colony counts.
Nanometres to cells
Viruses sit near 100 nm; bacteria are micrometres — the same number means very different threats.
Benefit vs risk map
The hub quadrant is a browsing aid — not a ranking of people or a clinical score.
Encounters are public-health
Influenza, TB and norovirus pages explain meetings, not diagnosis or treatment plans.
Time scales matter
Doubling time and seasonality change risk stories as much as diameter.
Compare on scores
Use Compare for familiarity/medical/benefit/risk — still teaching marks.
Scale FAQ
Is this lab guidance?
No. Educational scale and encounter context only — not a laboratory manual or medical advice.
Why is size on a log scale?
Microbes span orders of magnitude; a linear bar would squash viruses into invisibility.
Can I use this in a lab?
No. This is a teaching atlas of size and encounters, not a protocol.
Public-health encounter trees
Browse literacy paths for common encounter stories. Not diagnosis, not treatment, not lab protocols.
Educational only. If you are ill or worried, contact a clinician or local public-health service — this site cannot triage you.
Seasonal respiratory curiosity
You are learning about seasonal respiratory microbes — where should literacy start?
Food / gut encounter curiosity
You want literacy about food-linked or gut-linked meetings — pick a teaching door.
Skin / wound literacy path
Curious about bacteria often named in skin or wound stories?
Long-course respiratory literacy
Exploring slower, longer public-health stories?
Related on the scale
Tree of microbes
Bacteria
Single-celled prokaryotes with cell walls — the oldest widespread life form, and both partners and pathogens.
Familiarity 95Viruses
Packets of DNA or RNA that are not cells — they replicate only inside living hosts.
Familiarity 96Fungi
A eukaryotic kingdom of yeasts, moulds and mushrooms — chitin walls, external digestion, partners of plants.
Familiarity 80Archaea
A prokaryotic domain that is not bacteria — methanogens, extremophiles and no known human pathogens.
Familiarity 35Bacteriophages
Viruses that infect bacteria — Earth's most abundant biological entities, and a concept-level idea in medicine.
Familiarity 42Protozoa
Motile unicellular eukaryotes — a teaching grade that includes pond ciliates and a minority of serious parasites.
Familiarity 58