Tenth graders explore radioactive decay and half-life — the time for half of a radioactive sample to decay — learning how scientists use it to date fossils and rocks, and how nuclear processes differ from chemical ones.
Students will be able to…
Some atoms are unstable and “decay” over time — but always at a predictable rate. How does that steady halving let scientists date something thousands or even billions of years old?
Project this and advance the half-lives. Watch half the sample decay with each one — 100%, 50%, 25%, 12.5%…
Tap any phase to open the teacher moves and student actions.
Unstable atoms decay — but at a steady, predictable rate. How is that useful?
Students investigate.
Students explain.
Students elaborate.
Students conclude.
Aligned to the Next Generation Science Standards (High School Physical Science / Chemistry).
Develop models to illustrate changes in the nucleus during nuclear processes (fission, fusion, radioactive decay).
Use the periodic table to predict properties.
Investigate properties of matter.
Developing and using models.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students use carbon-14’s half-life to estimate the age of a fossil from the fraction of carbon-14 remaining. A printable half-life sheet is in the Science library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.