Half-life

Definition

Half-life is the time required for half of the atoms in a radioactive substance to decay. It is a crucial concept for understanding the dating of planetary surfaces.

5 Must Know Facts For Your Next Test

1. Half-life helps determine the age of rocks and meteorites by measuring the decay rate of radioactive isotopes.
2. Different isotopes have different half-lives, ranging from fractions of a second to billions of years.
3. Radiometric dating uses half-life measurements to estimate the absolute ages of geological samples.
4. The half-life concept is key in studying the history and evolution of planetary surfaces in our solar system.
5. Commonly used isotopes in radiometric dating include Uranium-238 (half-life ~4.5 billion years) and Carbon-14 (half-life ~5730 years).

Review Questions

• What is the significance of half-life in dating planetary surfaces?
• How does the half-life of an isotope affect its usefulness in radiometric dating?
• Name two isotopes commonly used in radiometric dating and their respective half-lives.

Related terms

Radioactive Decay:

The process by which an unstable atomic nucleus loses energy by emitting radiation.

Radiometric Dating:

A method used to determine the age of materials based on their radioactive decay rates.

Isotope:

Variants of a particular chemical element that have different numbers of neutrons but the same number of protons.