I.  Relative Age Dating
    A. Relative age of fossils
        1. Layers of sedimentary rock get older as you move down.
        2. The fossil near the top layer is younger.
    B. The principle of superposition - younger rock layers are formed on top of older
          layers
II. Disruptions of Rock Layers
    A. Folding can turn rock layers upside down or sideways.
    B. Faulting can make rock layers of different ages line up next to each other.
    C. Erosion removes layers of rock and creates gaps within layers.
    D. Molten igneous rock moves into cracks and hardens.
    E. Rules to remember when interpreting deformed rock
        1. Rock layers are horizontal before they deform
        2. A fault did not exist when the layers formed, so it is younger than the layers
            it cuts across.
III. Absolute Age Dating
    A. Radioactive isotopes
        1. Radioactive isotopes decay
        2. When it decays, it forms a new element called a decay product
    B. Half-Life
        1. Half of the atoms decay in a specific amount of time known as its half-life.
        2. Half-lives of isotopes vary depending on which isotope we measure
        3. Half-lives are unchanging
    C. Radiometric dating
        1. Rocks contain small amounts of radioactive isotopes when they form
        2. After the rock forms, the isotopes start to decay
        3. Scientists measure the amount of radioactive isotope present in the rock or
            fossil
        4. They compare this to the amount of the decay product present and calculate
IV.  Science and technology
       A. Scientists do not want to destroy fossils
       B. Scientists do want to see what is inside
       C. CAT scans give scientists a view of the inside of fossils
            1. Nanotyrannus had a brain twice as large as we first predicted
            2. Dinosaurs had a good sense of sight and smell