While many scientists contributed to our understanding of gases, the most prominent name associated with the idea that gases expand to fill their containers and are made of moving particles is Robert Boyle.

Here's why:

* Boyle's Law: Boyle, in the 17th century, established a relationship between the pressure and volume of a gas. This law, known as Boyle's Law, demonstrated that the volume of a gas decreases proportionally as pressure increases, suggesting the particles are moving and colliding with the container walls.

* The Kinetic Theory of Gases: While Boyle didn't explicitly state the idea of moving particles, his work laid the foundation for the later development of the Kinetic Theory of Gases. This theory, which emerged later in the 19th century, explains the behavior of gases based on the movement and collisions of particles.

It's important to note that the concept of gases being made of moving particles was a gradual development, with many scientists contributing over time. However, Boyle's work played a crucial role in establishing the foundation for this understanding.