Wall calendar and petri dish: what they have in common

1. Step 1. Wall calendar — is made of — Paper. Calendars were printed on paper.
2. Step 2. Paper — is made of — Bleach. Bleach makes paper white: without it wood pulp would be yellowish grey.
3. Step 3. Bleach — is used in — Antisepsis. Chlorine bleach kills germs and is used to disinfect.
4. Step 4. Antisepsis — uses — Germ theory of disease. Lister relied on Pasteur’s work.
5. Step 5. Germ theory of disease — is used in — Petri dish. Growing bacterial cultures.

Open Evothings