Half-Life Summary

Half-Life Definition

• Half-life is the time it takes for one half of a radioactive isotope to decay.
• Important for determining the danger and storage of radioactive materials.

Exponential Decay

• Half-life decay follows an exponential curve.
• At each half-life interval, half of the material decays.

Solving Half-Life Problems

• Use a table to solve half-life problems, including amount, half-life, and number of half-lives.

Example Problem: Phosphorus-32

• Phosphorus-32 has a half-life of 14.3 days.
• Starting with 8 mg, after 42.9 days (three half-lives), 1 mg remains.

Carbon-14 Dating

• Carbon-14 is used to estimate the age of fossils and artifacts.
• Carbon-14 combines with oxygen to form carbon dioxide, which is taken up by plants during photosynthesis.
• By measuring the percentage of radioactive carbon by mass and using the half-life of carbon-14, the age of a sample can be estimated.