In Mrs. M class, Friday we did the usual getting the homework stamped and looked over it. Following it we got off track talking about other things. In doing so we made it impossible to go over all of the neccessary information on the test. But we did go over half lives a bit more along with chain reactions and nucleor reactors. If you forgot, half-lives are the length of time it takes for a substance to decay over a period of time. Every set of years half of the substance dissapears until stable or gone. Chain reactions occur during Fission not fusion. Fission is the splitting of atoms and fusion is the combining of them. Fission occurs when a neutron hits a bigger nucleus causing large amounts of energy to be released in different elements and more nuetrons. More can be found on page 15 of the worksheets. Nuclear Reactors are divided into three parts. A.) Control rods absorb neutrons to slow down chain reactions B)Fuel Rods contain 3 percent of U-235 C.) Moderator slows down neutrons so they can be absorbed by the control rods. Again since we talked during class we ran out of time and did not cover Ionizing Radiation or Radon and we do not have to learn it for the test. Remember the test is MONDAY!