Radioactive Decay of Potassium and Argon: Understanding Half-Life

Understanding the decay of radioactive isotopes such as potassium to argon is crucial in various scientific fields, including geology and astrophysics. The half-life of an element represents the time it takes for half of the substance to decay into a more stable product.

In the case of potassium-40 decaying into argon-40, with a half-life of 1.25 billion years, the process is gradual yet predictable. After the first half-life of 1.25 billion years, 50% of the original potassium-40 remains. However, after another 1.25 billion years, which constitutes the second half-life, only half of the remaining 50% decays further.

Therefore, after 2.5 billion years, equivalent to two half-lives of potassium-40, only 25% of the original potassium would still be present. This demonstrates the consistent pattern of radioactive decay and how scientists can use this information to determine the age of various substances, including meteorites.