Absolute Dating

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Absolute Age Noun

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[ab-so-loot ayj]

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Absolute Age

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The exact age of a rock or material, representing the number of years that have passed since it formed.

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Example: This diagram shows a rock column where specific layers, like volcanic ash, are assigned a numerical age (e.g., 495 million years ago).

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Absolute Dating Noun

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[ab-so-loot day-ting]

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Absolute Dating

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The method used to determine the actual date or age of a rock or other object, often using radioactive decay.

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Example: This graph shows that after each half-life, the amount of a radioactive substance decreases by 50%, a principle used for absolute dating.

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Radioactive Decay Noun

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[ray-dee-oh-ak-tiv di-kay]

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Radioactive Decay

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The process where an unstable atomic nucleus loses energy by emitting radiation, causing one element to change into another.

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Example: A radioactive atom is unstable and releases particles and energy, a process called radioactive decay, to become more stable.

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Radioactive Isotope Noun

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[ray-dee-oh-ak-tiv ahy-suh-tohp]

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Radioactive Isotope

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An unstable version of a chemical element that is likely to undergo radioactive decay to become more stable.

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Example: This image shows isotopes of Carbon. They all have 6 protons, but different numbers of neutrons, which changes their mass and stability.

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Parent Isotope Noun

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[pair-uhnt ahy-suh-tohp]

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Parent Isotope

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The initial radioactive isotope that undergoes decay to form a new, more stable element called a daughter isotope.

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Example: The parent isotope is the original, unstable atom (shown as the 'Parent Nucleus') that decays over time into a new, more stable daughter atom.

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Daughter Isotope Noun

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[daw-ter ahy-suh-tohp]

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Daughter Isotope

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The stable product that results from the radioactive decay of an unstable parent isotope over a period of time.

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Example: An unstable parent nucleus decays, transforming into a new, more stable daughter nucleus by releasing a particle, a process used in absolute dating.

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Fission Noun

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[fish-uhn]

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Fission

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A nuclear process where an atom's nucleus splits into smaller fragments after being struck by a neutron.

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Example: A neutron strikes a large nucleus (Uranium-235), causing it to split into two smaller nuclei, releasing energy and more neutrons in the process.

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Half-life Noun

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[haf-lahyf]

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Half-life

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The specific amount of time it takes for half of the radioactive parent isotopes in a sample to decay.

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Example: This graph shows that for every half-life that passes, the amount of a radioactive material is reduced by half, from 100% to 50%, then 25%.

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Radiometric Dating Noun

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[ray-dee-oh-me-trik day-ting]

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Radiometric Dating

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The process of estimating a material's age by using the concentrations of radioactive substances and their daughter products.

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Example: Over time, unstable parent elements (like Potassium, 'K') in a rock decay into stable daughter elements (like Argon, 'Ar'), which scientists measure to find the rock's age.

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Uranium-Lead Dating Noun

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[yoo-ray-nee-uhm led day-ting]

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Uranium-Lead Dating

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A radiometric dating method that uses the decay of uranium into lead to find the age of rocks and minerals.

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Example: This diagram shows how parent atoms (Uranium) in a rock decay into daughter atoms (Lead) over time. By measuring the ratio of Uranium to Lead, scientists can determine the rock's age.