ANTH 110 Lecture Notes - Lecture 18: Rubidium, Mass Spectrometry, Relative Dating
Document Summary
Relative dating: the civil war occurred after the revolutionary war but before wwii. Absolute dating: the civil war occurred between 1861 and 1865. Stratigraphy: determining relative ages of layers while digging through the earth. The deep the layer, the older it is. Human activity makes determining relative ages of layers because structures or digging can cut into the layers and make them harder to determine. Radiometric dating: this uses the radioactive atoms that have decayed for their (half- life) to determine how old something is. Decay starts at the death for living organisms or after crystallization for minerals. Half life: the amount of time it takes for half of the atoms to decay. Rubidium is the longest of the isotopes at 47 billion years. Scientists use a mass spectrometer to determine how many atoms have decayed. This is a machine that counts and separates the decayed atoms.
