Ep 23. Isotopes as Clocks and Fingerprints

Nuclear Physics Explained season 1 episode 23, titled "Isotopes as Clocks and Fingerprints," explores the concept of isotopes and how they are used to determine the age of materials and identify the source of certain substances.

The episode begins with an explanation of isotopes, which are types of atoms that have the same number of protons but different numbers of neutrons. This difference in neutron number leads to differences in the atomic mass of the isotopes, and these differences can be used to distinguish between them.

The first application of isotopes discussed in this episode is radiometric dating, which is the use of isotopes to determine the age of materials such as rocks or fossils. The episode explains how certain isotopes decay over time in a predictable manner, allowing scientists to calculate how long it has been since the material was formed. Examples of isotopes commonly used for radiometric dating include carbon-14, uranium-238, and potassium-40.

Next, the episode delves into the concept of isotopic fingerprints. This refers to the unique pattern of isotopes found in a substance, which can be used to identify its origin. For example, different regions of the world have different isotopic compositions of certain elements like oxygen or hydrogen, and this can be used to determine where a substance like water or wine came from. Isotopic fingerprints can also help trace the movement of pollutants or other substances through the environment.

The episode then explores how isotopes can be used to track the movement of materials in biological systems. For example, carbon-14 can be used to determine when an organism died, and to track the movement of carbon through ecosystems. Isotopes of other elements like nitrogen and oxygen can also be used to understand how nutrients move through food webs and the environment.

Towards the end of the episode, the focus shifts to medical applications of isotopes. Specifically, the episode discusses how isotopes can be used for medical imaging. Certain isotopes like technetium-99m can be incorporated into molecules that are injected into the body, and then detected using specialized cameras that create an image of the internal organs. This allows doctors to diagnose diseases and track the progress of treatments.

Overall, "Isotopes as Clocks and Fingerprints" provides a fascinating look at the many uses of isotopes in science and technology. From dating ancient artifacts to diagnosing diseases, isotopes have proven to be an incredibly versatile tool for understanding the world around us.