Sheldon and Paige attend a carbon dating lecture. The lecturer asks Paige to explain carbon dating, which she does accurately.

Charlie explains radiocarbon dating and how it is used to calculate the approximate age of an object. To make his explanation more concrete, he uses an analogy involving a refrigerator and the number of ice cubes in it.

Neil deGrasse Tyson explains radioactive decay. He explains how we can determine the age of a rock using meteorites and illustrates that atoms undergo nuclear transmutations over time until they become stable elements.