1. Benefits & Dangers of: Radioisotopes

2. Dating (not that kind) C-14 used to date organic (previously living) materials living organisms incorporate C-14 into their structure, along with C-12 C-14 decays with known half-life 14 6 C  14 7 N + 0 -1  beta decay  comparing ratios of 14 C: 12 C –figure how many half-lives gone by since died –helps determine age of substance

3. ROCKS ROCKS U-238 decays to U-238 decays to Pb-206 (manysteps) Pb-206 (manysteps) over time: amount U  & amount Pb  - scientists compare ratio of U-238 to Pb-206 - scientists compare ratio of U-238 to Pb-206 to date rocks to date rocks

4. Chemical Tracers detect radioactive materials & decay products tracer: radioisotope used to follow path of material in system –P-31: determines P uptake in plants –C-14: maps C in metabolic processes –C-14: maps organic molecules & figures out reaction mechanisms

5. Industrial Applications  tracers kill bacteria and spores in food and mail Medical Applications Co-60 & Cs-137: destroys anthrax bacilli Co-60: kills bacteria in foods Tc-99: treatment of brain cancer

6. Medical Applications radioisotopes with short half-lives (quickly eliminated from body) –medical use diagnose & treat cancers I-131: diagnosis & treat thyroid disorders Co-60: gamma emitter –used to kill cancerous tumors

7. Nuclear Power Plants radioactivity used as fuel source to generate electricity –advantages: no contributions to greenhouse gases no mercury contamination of atmosphere

8. Radiation Risks damage normal tissue high doses can cause illness & death cause DNA mutations disposal of waste is difficult especially from nuclear power plants fuel rods are mix of many radioactive substances storage & transportation both problematic