K-Ar dating calculation | Life on earth and in the universe | Cosmology & Astronomy | Khan Academy

Recent questions

• How does potassium-argon dating determine the age of samples?

  Potassium-argon dating determines the age of samples by measuring the ratio of potassium-40 to argon-40 in a sample. This method relies on the principle of radioactive decay, where potassium-40 decays into argon-40 over time. By calculating the amount of remaining potassium-40 and argon-40 in a sample, scientists can determine the age of the sample based on the known half-life of potassium-40.

• What is the formula used in potassium-argon dating calculations?

  The formula used in potassium-argon dating calculations involves exponential decay. By using the formula A = A0 * e^(-kt), where A is the amount of remaining potassium-40, A0 is the initial amount of potassium-40, k is the decay constant, t is time, and e is the base of the natural logarithm, scientists can determine the age of a sample based on the amount of potassium-40 and argon-40 present.

• How is the decay constant (k) calculated in potassium-argon dating?

  The decay constant (k) in potassium-argon dating is calculated using natural logarithms. By rearranging the formula for exponential decay, scientists can solve for k by taking the natural logarithm of both sides of the equation. This allows them to determine the rate at which potassium-40 decays into argon-40, which is essential for calculating the age of a sample.

• Can you provide a concrete example of potassium-argon dating in action?

  In a concrete example of potassium-argon dating, scientists measure the ratio of potassium-40 to argon-40 in a sample. By applying the formula for exponential decay and calculating the decay constant (k), they can determine the age of the sample based on the amount of potassium-40 remaining. This method allows researchers to accurately date geological samples and artifacts by analyzing the radioactive decay of potassium-40.

• How is the age of a sample calculated using the ratio of potassium-40 to argon-40?

  The age of a sample is calculated using the ratio of potassium-40 to argon-40 in potassium-argon dating. By comparing the amounts of potassium-40 and argon-40 present in a sample, scientists can determine the age of the sample in years. This process involves using the decay constant (k) and the formula for exponential decay to accurately calculate the age of geological samples and artifacts.