Radioactive Decay

1. Radioactive Decay

2. Radioactive materials decay from the “Parent” material into the “Daughter Product”. Daughter Product Original “Parent” Material

3. Some atoms in the parent are isotopes • These atoms have a different number of neutrons than protons • They are unstable • As isotopes decay to stable daughter energy is released

4. You’ll never know which atoms will decay... (16 atoms)

6. … or when ...

7. But one thing we do know...

8. ...is that it always takes the same amount of time for half to disappear. (8 atoms)

19. Radioactive Decay • Parent – unstable • Daughter – stable • Half-life is the time required for HALF of the atoms of the unstable parent to decay to stable daughter

20. Radioactive Decay Data

21. Each half-life, the amount of atoms gets cut in half.

22. Since you don’t know how many atoms you started with, a ratio between parent to daughter will tell you how many half-lives have gone by. 100% parent 0% daughter 0 half lives

23. One half-life. 50% parent 50% daughter 1 half-life

24. Two half-lives. 25% parent 75% daughter 2 half-lives

25. Three half-lives. 12.5% parent 87.5% daughter 3 half-lives

26. Four half-lives. 6.25% parent 93.75% daughter 4 half-lives

27. Don’t worry about the last atom. You start with so many trillions that you never really get there. (It will just decay and then they’re all gone.)

28. Shape of curve similar for each radioactive isotope

29. Half Life • Continues indefinitely • Random and spontaneous • Not affected by temperature or pressure • Not affected by mass or volume of parent