Half-Life Problems

Algebra 1 · Axiom Academy

Work through a radioactive decay problem step-by-step and discover the half-life pattern. A radioactive substance has a half-life of 3 hours. If we start with 80 grams, how much remains after 9 hours? Nice work! You solved a half-life problem from scratch. Here's what to carry forward: Half-life definition: the time it takes for half of a substance to decay. The pattern: each half-life period, divide the amount by 2 . Multiple half-lives: count how many periods have passed with , then halve that many times. This same exponential pattern shows up in medicine dosages, cooling temperatures, and more — anywhere a quantity is repeatedly cut by a fixed factor.

This is the written version of the interactive lesson above. See the full Algebra 1 course.