1. Question 1 (Activity 12A, page 207) Do now: Paraire, 29 Kohi-tātea 2016 Use Einstein’s mass-energy equivalence (E=mc 2 ) to analyze and explain nuclear reactions Learning Outcome: Question 2 and 3 (Activity 12A, page 207) Homework Homework – due Tuesday 17 th

2. Calculate the “theoretical” mass of an alpha particle, using: Proton mass = 1.67338 x 10 -27 kg Proton mass = 1.67338 x 10 -27 kg Neutron mass = 1.67483 x 10 -27 kg Neutron mass = 1.67483 x 10 -27 kg 2p + 2n = 6.69642 x 10 -27 kg 2p + 2n = 6.69642 x 10 -27 kg Another Nuclear Puzzle: The actual mass of an alpha particle has been measured to be 6.64591 x 10 -27 kg What’s going on??? What’s going on???

3. Explain this “mass deficit” in terms of nuclear binding energy Explain this “mass deficit” in terms of nuclear binding energy Use the concept of binding energy per nucleon to explain the stability of nuclei Use the concept of binding energy per nucleon to explain the stability of nuclei Convert Joules (J) to electron volts (eV) Convert Joules (J) to electron volts (eV) Today’s Learning:

4. Binding Energy Mass number 50 100150 200 Binding energy per nucleon (MeV) 2 4 6 8 56 Fe 238 U 4 He 7 Li Fusion Fission