You should see a white crescent called the lunula. The cuticle is the piece of skin that overlaps the hard nail and touches the lunula. You may be wondering what they do, or why you need them. If you get frequent manicures, they may be smooth and even, pushed back as far as they'll go.If not, they may be ragged and torn, or creeping up on the nail.he cuticle is the piece of skin that overlaps the hard nail and touches the lunula. You may be wondering what they do, or why you need them. If you get frequent manicures, they may be smooth and even, pushed back as far as they'll go.
Index fossils. Radiometric dating. The Age of Dinosaurs was so many millions of years ago that it is very difficult to date exactly. Scientists use two kinds of dating techniques to work out the age of rocks and fossils. The first method is called relative dating.
With the exception of Carbon-14, radiometric dating is used to date either igneous or metamorphic rocks that contain radioactive elements such as uranium. And even though various radioactive elements have been used to date these rocks, for the most part, the methods are basically the same. They consist of measuring the amount of radioactive (mother) element and comparing it to the amount of stable (daughter) element. A discussion of the Uranium/Lead method follows. Uranium is radioactive, which means it is in the process of changing from an unstable element into a stable one.