What did Thomas Graham contribute to the study of gases?

Thomas Graham is best known for his pioneering work in the study of gas diffusion, which is the process by which gas molecules spread from areas of high concentration to areas of low concentration. He formulated Graham's Law of Effusion, which describes how the rate of effusion (the process of gas escaping through a tiny hole) is inversely related to the square root of its molar mass. This became a foundational concept in understanding the behavior of gases and their movement.

Graham's research demonstrated that lighter gas molecules diffuse faster than heavier ones, which is a critical insight for both chemistry and physics. His extensive studies laid the groundwork for future explorations into gas behavior and properties. This focus on gas diffusion distinguishes his work in the field, making the contribution related specifically to the study of how gases interact as they spread throughout a given volume.