🧪 Science & Lab Tools

Radioactive decay from a half-life — where the average atom lives 44% longer than the half-life and ten half-lives is 1/1024, not a thousandth.

C1V1 = C2V2 with the off-by-one made explicit — a 1:10 dilution takes nine parts of diluent, not ten, and the error is worst at small factors.

Steps, volumes and compounded error for a serial dilution — where six steps at 2% error apiece is 12.6%, not 2%.

Carrier and affected rates from an allele frequency — where carriers outnumber affected people by exactly 2p/q, which is 198 to 1 at a 1% allele.

Punnett squares plus the family odds — two carriers with four children have a 68% chance of an affected child, not a certainty, and 32% of none.

Which ABO blood types two parents can and cannot have — where an AB parent and an O parent have children of type A or B, matching neither of them.