Okay kiddo, so g2 in mathematics is something called a Lie group. A Lie group is like a special club where all the members follow certain rules. In g2, the members are like points in space that move around according to these rules.
Now, there are a lot of different Lie groups, but g2 is special because it is very small with only 14 members. It's kind of like a small group of friends who all have to stay close together and move around in a certain way.
This club follows some special rules which are called the algebra of g2. It's like a secret code that tells you how the members should move and interact with each other. When you study g2, you learn how to decode this secret language and understand how everything works.
Scientists use g2 in a lot of different ways, like in physics to help explain the movement of particles, or in geometry to study the shape and structure of objects. It's a very cool and powerful tool, and even though it might seem complex and hard to understand, it's important to keep learning and exploring this fascinating field of mathematics.