JOURNAL #3 – ABSOLUTE DATING

1. Divide the following numbers in halfa) 100 b) 50 c) 25 d) 12.5

2. What were four laws or rules for relative dating?

3. How is relative dating different from absolute dating?

ABSOLUTE DATINGObjective: Understanding how rocks are given an age based on radioactive elements.

ABSOLUTE DATINGAbsolute Dating

An actual number of years

When events occurred and organisms lived

Exact age

UNSTABLE RADIOACTIVE DECAY NUCLEI

Radioactive Decay

All rocks, artifacts and fossils are made up of elements and isotopes

ISOTOPES• Isotopes: variation of the

same elements with a different number of neutrons

HALF-LIFEHalf-Life

The time it takes for half of the atoms in an object to decay into another element; Constant and never changes

Radioactive nuclei decay at a known rate which is called their half-life

HALF-LIFEParent Material – radioactive

isotope

Daughter Product – the result of the radioactive isotope decaying by its half-life

HALF-LIFERatio of Daughter Products

Used to determine the exact age of rocks, artifacts, and fossils