Page 1 Page 2 Radioactive decay involves the changing of a radioactive atom into another radioactive atom. For example, rocks an
d minerals may contain potassium-40 that changes into argon-40. Mass spectrometers measure the number of these atoms in a rock or mineral sample. This information and knowing the half-life of potassium-40 can help determine the age of rock layers. The half-life of potassium-40 is 1.3 billion years. The potassium-40 in rocks and minerals will decay through many half-lives until all of them change into argon-40. How many atoms will there most likely be at the third half-life of potassium-40 in this model? A model rock layer had 50 pennies (atoms of potassium-40). How old is the rock layer?
During meiosis one cell? divides twice to form four daughter cells. These four daughter cells only have half the number of chromosomes? of the parent cell – they are haploid. Meiosis produces our sex cells or gametes? (eggs in females and sperm in males).
