Half-Life


How Long it Takes for Half of the Original Atoms in a Sample to Decay to a "Daughter" Product

The daughter product may also be radioactive, and may decay into another product.

Parent Daughter Half Change in...
Carbon-14 Nitrogen-14 5730 years
Uranium-235 Lead-207 704 million years
Uranium-238 Lead-206 4,470 million years
Potassium-40 Argon-40 1,280 million years
Thorium-232 Lead-208 14,010 million years
Rubidium-87 Strontium-87 48,800 million years