Section 8-3

Radioactive Dating

Intro To Matter

• Elements – the simplest form of matter (i.e. Hydrogen (H) or Oxygen (O)– Atoms – the smallest particle of an element

• Compounds – two or more elements bonded together (i.e. H2O)– Molecules – the smallest unit of a compound

• The Periodic Table Example

Radioactive Decay

• When atoms of an element break down (decay) to form another element– Half-life• The amount of time it takes for half of the radioactive

element to decay• Used to determine the absolute age (age in years) of

rocks

Determining Absolute Age

• Potassium-Argon Dating– Used to date rocks because the half-life is 1.3 billion

years• Example:

• Carbon-14 Dating– Used to date the fossils of living things because it’s half-

life is 5,730 years• Example: