| A | B |
|---|
| absolute dating | the process that uses the properties of atoms in rocks and other objects to determine their ages |
| atom | the particles or "building blocks" of which all matter is composed |
| proton | largest part of the atom determines the characteristics of the atom |
| electron | smallest part of the atom; leaves atom as a beta particle during decay |
| isotopes | atoms of the same element that have different number of neutrons |
| half life | the rate at which each radioactive parent material decays to its daughter product |
| radioactive decay | a process that isotopes undergo that results in a new element being formed |
| radiometric dating | by measuring the amounts of parent and daughter materials in a rock and by knowing the half-life of the parent, a geologist can calculate the absolute age of the rock |
| uniformitarianism | principle that states that processes occurring today are similar to those that occurred in the past, therefore the Earth is very old |
| John Hutton | in the 1700s he observed that the processes were changing the rocks and land around him were very slow, and he deduced that they had been just as slow throughout Earth's history |
