# Radioactive Decay as a Measure of Age

##### Study Tip
You may have studied exponential and logarithmic functions in your algebra class. Scientists use these functions in order to calculate the duration of a half-life and the age of a material.

## How It Works

• Unstable, radioactive isotopes decay into more stable, lighter atoms.
• Alpha decay emits 2 protons and 2 neutrons, while Beta decay emits 1 electron.
• The bigger, less stable isotope is called the parent isotope. It emits either alpha particles or beta particles to form smaller, more stable isotopes called daughter isotopes.
• Scientists measure the time it takes for parent isotopes to decay into daughter isotopes by half-lives. The half-life of a radioactive substance is the amount of time it takes for half of the parent atoms to decay.
• Scientists examine the composition of parent and daughter isotopes in a radioactive substance in order to determine how many half-lives have passed. This can help scientists figure out the age of the particle.
##### Study Tip
You may have studied exponential and logarithmic functions in your algebra class. Scientists use these functions in order to calculate the duration of a half-life and the age of a material.
A parent isotope emits an alpha particle to become a daughter isotope.
##### Concept Check
• What are the products of alpha decay? Beta decay?
• What is the difference between the parent isotopes and its daughter isotopes?
• What is a half-life?