Though still heavily used, relative dating is now augmented by several modern dating techniques.
Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content.
Isotopes There are two stable naturally occurring isotopes of carbon, carbon-12 and carbon-13.
Carbon-12 makes up almost 99% of the carbon found on Earth.
Diamonds are also used for their hardness in cutting tools and precision instruments. People have known about carbon as a substance since ancient times.
French scientist Antoine Lavoisier determined that diamond was made of carbon in 1772. Carbon gets its name from the Latin word "carbo" meaning charcoal or coal.
It is even used to make black ink for printers and painting.
Graphite is often used in making batteries, brakes, and lubricants.The curie was named after Marie and Pierre Curie who discovered the element radium. The half-life of an isotope is the time on average that it takes for half of the atoms in a sample to decay.For example, the half-life of carbon-14 is 5730 years.Carbon-14, or radiocarbon, is a naturally occurring radioactive isotope that forms when cosmic rays in the upper atmosphere strike nitrogen molecules, which then oxidize to become carbon dioxide.Green plants absorb the carbon dioxide, so the population of carbon-14 molecules is continually replenished until the plant dies.In its diamond allotrope, carbon is the hardest known substance in nature.