Understanding Electricity

Introduction

• Electricity is crucial to modern civilization.
• To understand electricity, we need to explore atomic structure.

Atomic Structure

• Atoms: Smallest units, viewable via scanning tunneling microscope.
• Bohr Model: Simplified representation, not to scale, and 2D.
  • Nucleus: Contains protons and neutrons.
  • Electrons: Orbit the nucleus, responsible for electricity.

Electrons and Electric Charge

• Electron Movement: Forms an electric current.
• Protons: Positive charge.
• Electrons: Negative charge.
• Neutral Atom: Equal number of protons and electrons, net charge of zero.
• Charge Imbalance:
  • More electrons than protons: Negatively charged.
  • Fewer electrons than protons: Positively charged.

Visualization of Charges

• Color Coding:
  • Positive charge: Red.
  • Negative charge: Blue.
  • Neutral charge: Purple.
• Ions: Charged atoms (positive or negative).

Electron Shells

• Inner shell: Holds 2 electrons.
• Second shell: Holds 8 electrons.
• Third shell: Holds 18 electrons.
• Electrons fill shells from inside out.
• Valence Shell: Outermost shell, determines atom's reactivity.

Static Electricity

• Example: Shuffling feet on a carpet builds a positive charge.
• Insulators: Do not easily give up electrons.
• Conductors: Easily transfer electrons (e.g., the human body).
• Charge Imbalance: Restored by touching a conductor (e.g., door knob).

Conductors and Insulators

• Conductors: High electron mobility (e.g., copper).
• Insulators: Low electron mobility (e.g., plastic).
• Wire Example: Copper core (conductor) and plastic shell (insulator).

Electrical Circuits

• Electric Circuit: Path connecting points with charge imbalance.
• Power Source: E.g., battery pushes out and attracts electrons.
• Electron Flow: From negative to positive.
• Continuous Path: Necessary for current to flow.
• Short Circuit: Dangerous, no resistance, can cause overheating.

Safety Measures

• Fuses: Cut the current flow when it becomes too high.

Future Topics

• Generating power, resistance, voltage, amperes, batteries, fuses, motors, transformers, etc.
• Importance of safety in electric circuits.