Absolute Dating

• Radioactivity was discovered in the 19th century by Marie and Pierre Curie.
• Radioactivity uses radioactive isotope decay to develop a method for determining absolute ages of rocks.
• Radioactivity uses radioactive isotope decay to develop a method for determining absolute ages of rocks.
• Radioactive decay

  An unstable atomic nucleus is transformed into an atomic nucleus of a different element.
• The rate of unstable isotope determine the absolute dates of rocks and minerals.
• Alpha decay is the emission of an alpha particle from a nucleus.
• What is an alpha particle?

  Helium nucleus (2P, 2N)
• What happens to atomic number and mass in alpha decay?

  Atomic number decreases by 2, mass number decreases by 4.
• What is beta decay?

  An electron Is released and turns into a proton
• What happens to the atomic mass and number in beta decay?

  Atomic mass stays the same, atomic number increases by 1.
• Electron Capture

  a proton captures an electron and becomes a neutron
• Hal-life

  the time it takes for one half year of the original unstable radioactive parent to decay to a new stable daughter element
• Hag-life is the most common method of determining an absolute decay
• Radiocarbon dating

  can only be used in organic matter (wood, bone, shell)