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.
Age of the Earth. Scientists determined the Earth's age using a technique called radiometric dating. Radiometric dating is based upon the fact that some forms of chemical elements are radioactive, which was discovered in 1896 by Henri Becquerel and his assistants, Marie and Pierre Curie.The discovery gave scientists a tool for dating rocks that contain radioactive elements.The nucleus of an atom is made up of protons and neutrons.) For example, the element carbon, which always has six protons in its nucleus, has three isotopes: one with six neutrons in the nucleus, one with seven, and one with eight. Some isotopes are stable, but some are unstable or radioactive.