In particle physics, everything is made up of tiny particles called quarks and leptons. These particles are divided into families called generations.
Think of it like a family tree! You have your grandparents, parents, and siblings. In particle physics, quarks and leptons also have "parents" and "children" in the form of higher and lower energy levels.
The first generation is the most stable and includes the particles that make up ordinary matter, like protons and electrons. The second generation includes particles that are similar to those in the first generation but are heavier and less stable. The third generation includes even heavier and even less stable particles.
Like with a family tree, each generation inherits characteristics from its predecessors but also possesses unique traits. In particle physics, each generation interacts differently with other particles and forces.
Understanding generations helps physicists better understand the building blocks of the universe and how they interact with each other.