Half-life: Every radioactive isotope has a half-life.

2. Half-life: Every radioactive isotope has a half-life. This is the amount of time required for one-half the radioactive nuclei to decay into a stable element Isotope half-life radiation carbon-14 5730 years beta potassium-40 1.25 x 109 yrs beta, gamma radium-226 1.6 x 103 yrs alpha, gamma radon-222 3.8 days alpha polonium-210 138 days alpha uranium-238 4.5 billion yrs all 3

3. Carbon dating: C-14 has a half-life of 5730 years and is used to date artifacts made of carbon – HUMAN bones, documents, plants All living organisms have C-14 and C-12 in a fixed ratio. After death, the ratio changes as C-14 decays to N-14. So, by comparing C-14 to C-12 the approximate age of the item can be determined between 200 and 50,000 yrs

4. Ex: an archaeologist digs up a skull that has 1/64 of the normal amount of carbon 14 that should be present. Approximately how old is the bone? 1/2 1/4 1/8 How many half lives have occurred? 1/16 1/32 6 half lives x 5730 yr = 34,380 yrs half life 1/64