1. Lab 525 ONLINE LESSON

2. If viewing this lesson in Powerpoint Use down or up arrows to navigate

3. Do take notes as we peruse through this lesson…

4. Radiometric Dating

5. A question that is often asked… How old is the earth?

6. And the answer is…

7. Pretty Old

8. Radiometric dating is the process of measuring the age of rocks

9. By measuring the age of rocks, geologists can determine the age of a number of geologic events...

10. To include the age of the earth!!!

11. Radiometric dating is based on the concept of radioactivity…the disintegration (falling apart) of atoms

12. What is an atom?

13. An atom is the smallest particle in the universe with a distinct set of chemical characteristics…..

14. An atom is a structure…it is a package of particles

15. Everything in the universe is comprised of atoms…bicycles

16. Cellphones

17. Dumbasses

18. Everything

19. An atom is comprised of three basic components

20. ATOM PROTON (positively charged) P NEUTRON (neutral) N ELECTRON (negatively charged) e-

21. The electron orbits the nucleus which contains the protons and neutrons e- NUCLEUS

22. RULE: The number of protons determines the chemical identity of an element

23. For instance… -all Hydrogen contains 1 proton… -all Helium contains 2 protons… -all Uranium contains 92 protons…

24. Element = a substance that cannot be broken down into other substances by chemical means…

25. For instance… Hydrogen is an element Helium is an element Uranium is an element

26. Carbon-12 is a species of carbon… CARBON 12C

27. It contains 6 protons and 6 neutrons…for a total of 12 particles in the nucleus CARBON 12C

28. Carbon-14 is another species of carbon… CARBON 14C

29. Carbon-14 contains 6 protons but 8 neutrons…for a total of 14 particles… CARBON 14C

30. The neutron count may vary but the proton count remains the same…6 protons… CARBON 14C

31. SO: The number of protons determines the chemical identity of an element

32. Decay types are part of Radioactivity …there are three types to be concerned with…

33. DECAY TYPES ALPHA P P N N e- BETA N P ELECTRON CAPTURE P N e-

34. DECAY TYPES ALPHA P P N N 2 protons and 2 neutrons are thrown out of the nucleus…this reduces the number of protons and thus changes the element…

35. DECAY TYPES A neutron turns into a proton e- BETA N P This will change the element

36. DECAY TYPES A proton turns into a neutron This will change the element ELECTRON CAPTURE P N e-

37. With all 3 decay types…elements will change their chemical identity because of the change in the number of protons…

38. A common decay series is 238U/206Pb URANIUM = PARENT LEAD = DAUGHTER

39. A decay series is the progression of the disintegration of elements…a start to finish process…

40. This beginning to end process is the essence of radiometric dating…

41. For instance… Uranium 238 is a parent element and it decays over time to to Lead 206… 238U92

42. The decay process starts out with 92 protons and 146 neutrons for a total of 238 particles in the nucleus… 238U92

43. And includes a series of steps before uranium turns into lead… 238U92

44. 2 protons and 2 neutrons are ejected from the nucleus and changes the element… uranium to thorium 238U92

45. A neutron is converted to a proton and changes thorium to paladium… 234Th90

46. And so on and so on… 234Pa91

47. 234U92

48. 230Th90

49. 226Ra88

50. 222Rn86