9.0 ELECTROSTATICS I

Electrostatics is the branch of physics that deals with stationary electric charges and their interactions. This chapter transitions from the structure of the atom to observable phenomena like attracting small pieces of paper or the shock from a doorknob. Understanding electrostatics is essential for grasping more advanced topics in electricity and even natural phenomena like lightning.

9.1 INTRODUCTION TO STATIC ELECTRICITY

Static electricity refers to electric charges that are at rest (not moving). When you rub a plastic comb on your hair and it picks up small pieces of paper, you are demonstrating static electricity. The charges are 'static' until they find a path to move (discharge).

9.2 THE STRUCTURE OF THE ATOM

All matter is made of atoms. An atom consists of a central nucleus surrounded by electrons. Understanding the atom is key to understanding how objects become charged.

9.2.1 Subatomic Particles

• Protons: Located in the nucleus. They have a positive (+) charge. The number of protons defines the element.
• Neutrons: Also in the nucleus. They have no charge (neutral). They add mass to the atom.
• Electrons: Move around the nucleus in shells/orbitals. They have a negative (−) charge. They are much lighter than protons and neutrons.

9.2.2 Electric Neutrality

In a