How electricity works

We live in an electric world – lightning is electricity, electric currents run through our bodies.

electromagnetic waves, radio waves, wifi

voltage as electrical pressure

electricity as promethian fire, ben franklin, lodestones, static, the amount of electricity in the human body, the amount generated in singapore, in the world, in a single lightning storm

the magic of sillicon transistors

its displacement of fire as the center of our lives

First functional electricity – Coney Island, Thomas Edison, 1903.

Atoms made up of protons (positively charged), neutrons (no charge) and electrons (negative charge). Electrons can jump from atom to atom.

Electric current is the movement of electrons from atom to atom. Measured in Amperes, or amps. (What about wattage?)

Lightning is a form of electricity. (How powerful is it?) Negatively charged clouds, positively charged ground. Discharged.

Voltage = potential difference, “electrical pressure” – measured in volts.

Water flowing through pipes. Squirt gun vs fire hose.

Current = AMOUNT of electrical current – measured in amperes. Numbers of electrons. 1 Amp of current = 16 quintillion electrons / second. 1 Amp can stop a human heart (??)

Fossil fuel, moving water, wind – spin turbine, spins magnet in coil of metal wire, causes electrons to move, flows through power lines.

Direction of the current is changed several times per second. (How many times? Why?)

Conductors, insulators.

High voltage power lines usually aluminium – less conducive but lighter.

1977 – massive NYC blackout, mobs looted stores, set fire to buildings. Damage and theft cost millions.

Edison vs Tesla (Serbian). Tesla prefers AC and tries to persuade Edison.

Edison promised $50,000 to Tesla for solving an engineering problem. Tesla solves it, asks for the money. Edison pretends its a joke. Tesla quits.

Tesla is introduced to Westinghouse.

Conductivity: Platinum, gold, silver, aluminium, copper.

Alternating current vs Direct Current

Transformers

Voltage

Transistors

Tiny switches that switch on and off without any moving parts.

This works because it uses silicon, which is a semi-conductor.

How Wifi Works

Radio waves are long (30m)

X rays are short (10nm)

Visible light (400-700nm)

Wifi (6ft… 1.8m) – 12cm wavelength

20-30m across

we’re all bathing in electromagnetic radiation every day… but it’s the tiny/nano stuff that hurts us (x-rays, gamma rays)

Wifi is affected by concrete, wood, (lead?), other wifi

You can buy wifi paint that blocks other wifi from interfering (how does it work?)

How does it work? Off/On binary code, transmitted at the speed of light. (Missing nuance here… but good enough)