Rocks have naturally occurring and spontaneously radioactive atoms in them, such as carbon-14. These element isotopes decay into other types of atoms over millions of years. Therefore, by measuring the amount of these radiometric substances, and knowing the half-life of the isotopes, it is possible to postulate the age of a rock to within certain ranges of error.
Conduction is the transfer of heat between objects in contact with each other as a result of molecular action. Conduction occurs within and between all states of matter.
