Fundamentals of Electricity: History and Atomic Structure

Fundamentals of Electricity

Etymology and Early Observations

Electricity originates from the Greek word "elelctron," meaning "amber." This name was given because the Greeks observed that fossil resin used in jewelry, when rubbed, attracted light objects.

Thales' Discovery

Thales noted that when amber was rubbed with force using cloth, silk, wool, or skin, it would attract light materials.

William Gilbert's Contribution

William Gilbert observed that this attractive behavior was not limited to amber and similar substances. He recognized these phenomena as electrostatics.

Causes and Natural Phenomena

These electrostatic phenomena are caused by the behavior of atoms in each material. Natural phenomena associated with electricity include:

• Lightning storms.
• Electric shocks from certain fish, such as the eel and torpedo fish.

Pioneers in Electrical Science

Key figures in the development of electrical understanding:

• Volta (Lap): Built the first electric stack (battery).
• Oersted: Discovered that an electric current could create a magnetic field.
• Faraday: Building on previous investigations, he showed that a magnetic field could generate an electric current.
• Thomas Alva Edison: Patented the incandescent light bulb with a bamboo filament.
• Nikola Tesla: Created the primary hydroelectric power generator at Niagara Falls, illuminating 50,000 homes in New York.

Matter and Atomic Structure

Composition of Matter

Matter is composed of elementary particles called atoms.

The Atom

The atom comprises a nucleus and an electron cloud (cortex).

Components of the Nucleus and Cloud

• The nucleus contains protons and neutrons.
• The cortex contains electrons.

Electric Charge of Particles

• Neutrons have no charge.
• Protons are positively charged.
• Electrons are negatively charged.

Atomic Charge States

• Negatively Charged Atom: An atom is negative because it has an excess of electrons.
• Neutral Atom: An atom is neutral when the number of protons and electrons is equal.

The overall charge sign depends on the balance between positively and negatively charged particles.

Electric Current and Materials

Electric Current Definition

Electric current is the continuous and orderly displacement of electrons circulating in a specific direction.

Convention vs. Reality

• Conventional Current Sense: Defined as flowing from positive to negative.
• Actual Flow: In reality, electric charges (electrons) flow from negative to positive.

Materials for Conducting Current

Electric current can be driven through solids, liquids, and gases.

Conductors

Materials that allow electric current to pass through them easily. Silver is the best electrical conductor.

Insulators

Materials that do not allow electric current to pass easily. Examples include wood, plastic, ceramic, cork, and rubber (cautxil).

Semiconductors

These materials can act as insulators or conductors depending on factors like temperature.

Conductivity in Fluids

Yes, liquids and gases can permit the passage of electric current under certain conditions.