Fundamental Concepts: Atoms and Electrification Principles

Atom: Fundamental Building Blocks

In chemistry and physics, an atom is the smallest unit of a chemical element that retains its identity and properties, and cannot be divided by chemical processes.

The concept of atoms as indivisible building blocks that make up the matter of the universe was proposed by the Atomistic school in ancient Greece. However, their existence was not proven until the nineteenth century. With the development of nuclear physics in the twentieth century, it was discovered that atoms could be divided into smaller particles.

Electrification: Gaining or Losing Charge

In physics, electrification refers to the process of an electrically neutral body gaining or losing electrical charges, typically electrons.

Electrification by Contact

You can charge a neutral body by simply touching it with a pre-charged body. In this case, both bodies acquire the same type of charge. For example, if a neutral body touches a positively charged body, the neutral body will also become positively charged.

This occurs because free electrons will transfer from the body that holds a greater quantity to the one with a lesser proportion. This flow continues until the magnitude of the charge is the same in both bodies.

Electrification by Friction

When rubbing two electrically neutral bodies (where the number of electrons equals the number of protons), both become charged: one positively and one negatively.

Consider these examples:

• Rubbing a bar of glass with a piece of silk results in a transfer of electrons from the glass to the silk. The glass acquires a positive electrical charge by losing electrons, which are attracted by the silk, making the silk negatively charged.
• If you rub a plastic rod with a piece of wool, there is a transfer of electrons from the wool to the rod.
• Example: If you rub a balloon on your head and then place it near another person's head, their hair will stand up due to static electricity.

When both bodies are electrically charged, they exert a force in a given area. This force depends on the amount of charge gained or lost, and the area where this force is exerted is called an electric field.