Here's why:

* Atoms and Electrons: All matter is made of atoms. Atoms have a central nucleus containing protons (positively charged) and neutrons (no charge), surrounded by electrons (negatively charged).

* Friction and Electrons: When you rub two objects together, the friction creates a lot of energy. This energy can cause some of the outer electrons to become "loosened" from their atoms. These loose electrons can then be transferred from one object to the other.

* Static Electricity: The object that gains electrons becomes negatively charged, while the object that loses electrons becomes positively charged. This imbalance of charge is called static electricity.

Think of it like this: Imagine you have two containers full of marbles. When you rub the containers together, some marbles can jump from one container to the other. The container that gains marbles becomes "negatively charged" with marbles (electrons), and the container that loses marbles becomes "positively charged" because it has fewer marbles.

Let me know if you'd like more explanation about how static electricity works!