Topic hub

How Things Work: the machinery behind everyday things

Most of the things you rely on every day run on a mechanism you have never had a reason to examine. How does sound get from the air into your head? What is a screen doing when it shows you a colour? Why does one material shatter and another bend? This hub is the plain, physical account of how ordinary things work — built up from causes, not taken on faith.

Why the mechanism is the interesting part

Knowing that something works is useful. Knowing why is what lets you predict it, repair it, and recognise when a claim about it is nonsense. A fact without its mechanism is only half a fact, and the half that stays with you is usually the how. Each explainer here aims for the point where the thing stops being magic and starts being obvious.

Where to start

The first guide takes bone conduction — how vibrations reach your inner ear straight through the bones of your skull, and why your own recorded voice never sounds quite like you. It is a good example of the pattern this hub follows: one everyday puzzle, traced back to the physics that settles it. More mechanisms follow as the hub grows.

Last reviewed 10 July 2026

Understand it

How bone conduction lets you hear through your skull

How vibrations reach your inner ear through the bones of your skull, and why your recorded voice never sounds quite right.

Guide
What MIL-STD-810 is (and what 'rugged' really claims)

The US military environmental-test standard that 'rugged' devices cite — and why the specific method tested matters more than the label.

Guide
How earthquake early-warning systems buy you seconds

Why a network of sensors can warn phones and infrastructure seconds before an earthquake's damaging shaking reaches them.

Guide
The false-belief task: the experiment behind theory of mind

The classic experiment that pinpoints when children can hold someone else's mistaken belief apart from the truth.

Guide
Why your own voice booms when you block your ears

Why sealing your ear canal makes your own voice sound loud and hollow — the everyday face of bone conduction.

Guide
Two accounts of how you read other people's minds

The two leading accounts of mind-reading — running an inner theory versus simulating the other person — and where they disagree.

Guide
How a tuning fork finds the cause of hearing loss

How two quick tuning-fork tests separate a blockage in the outer or middle ear from a problem in the cochlea or nerve.

Guide
The lightbulb cartel that defined planned obsolescence

How a 1920s agreement to shorten lightbulb life became the clearest documented example of built-in obsolescence.

Guide
How the Global Supply Chain Works

From factory to doorstep: the hidden system behind everything you buy.

Guide
How Internet Search Engines Work

What happens when you type a query? The technology behind finding information instantly.

Guide
How the Global Financial System Works

The invisible infrastructure that lets you send money across borders in seconds.

Guide
How the Water Cycle Works

The endless journey of Earth's water, from clouds to rivers and back again.

Guide
How the Immune System Works

The body's defense network: how it fights infections and remembers past invaders.

Guide
How the Electricity Grid Works

The invisible network that delivers power from plants to your plug, 24/7.

Guide
How solar panels convert sunlight into electricity

Photons knock electrons loose in silicon, creating an electric current.

Guide
How GPS determines your exact location

GPS satellites broadcast time; your device triangulates your position.

Guide
How WiFi transmits data wirelessly

WiFi converts data into radio signals that travel between devices and routers.

Guide
How vaccines train your immune system

Vaccines teach your body to recognize and fight off specific pathogens.

Guide
How batteries store and release electrical energy

Chemical reactions inside a battery push electrons through an external circuit.

Guide
How encryption keeps your data secure

Encryption turns readable data into ciphertext that only authorized parties can decode.

Guide
What is neuroplasticity?

How the brain rewires itself through experience and recovery.

Guide
How does the placebo effect work?

Why a sugar pill can make you feel better.

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How do sleep cycles work?

The stages of sleep and what happens in each.

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What are mirror neurons?

How the brain mirrors others' actions and emotions.

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What is cognitive dissonance?

The discomfort of conflicting beliefs and how we resolve it.

Guide
How does the brain process pain?

The neural pathways that create the experience of pain.

Guide
How the Human Digestive System Works

Step-by-step breakdown of digestion and nutrient absorption.

Guide
How the Human Circulatory System Works

The heart’s pumping action and the double-loop circulation pathway.

Guide
How the Solar System Works

The structure and dynamics of the Sun, planets, and orbits.

Guide
How GPS Works

Satellite signals, time synchronization, and position calculation.

Guide
How the Human Brain Works

Neural communication and the functions of major brain areas.

Guide
How does a touchscreen work?

Capacitive and resistive touchscreens sense touch differently.

Guide
How the Climate System Works

Energy balance, greenhouse effect, and feedback loops.

Guide
How does a QR code work?

QR codes store information using patterns of squares and error correction.

Guide
How does a compass work?

A compass needle aligns with Earth's magnetic field to indicate north.

Guide

Follow the rabbit hole

One idea leads to the next. Start anywhere.

  1. What is compound interest?A plain explanation of compound interest, why it accelerates, and why it matters for anyone saving or borrowing.
  2. How compound interest worksThe four moving parts — principal, rate, frequency and time — and how each one changes what you end up with.
  3. The compound interest formula, explainedWhat FV = P(1 + r/n)^(nt) actually says, term by term, with a worked calculation you can follow.
  4. The Rule of 72A mental shortcut for how long money takes to double — how it works, how accurate it is, and where it breaks down.
  5. Compound interest and inflation: real returnsWhy the growth you see is not the growth you get, and how to think about returns after inflation.
  6. Why compound interest makes pensions workHow decades of compounding do most of the work in a pension, and why starting earlier beats contributing more.

Questions people ask

Why does my recorded voice sound so different?

Live, you hear your own voice two ways at once — through the air and through the bones of your skull. Bone conduction adds low frequencies that make it sound fuller. A recording captures only the air-conducted sound, so it comes back thinner and higher: the version everyone else hears.

Can bone conduction help people who cannot hear?

It can help some kinds of hearing loss. If the outer or middle ear cannot pass sound but the cochlea still works, a bone-conduction or bone-anchored device sends vibration straight to the cochlea, bypassing the blockage. It does not help when the cochlea or auditory nerve itself is the problem.

Convert english to sinhala?

සූර්ය පැනල් විදුලිය නිපදවන්නේ හිරුඑළියේ ෆෝටෝන සිලිකන් සෛලවලට වැදී, ඉලෙක්ට්‍රෝන නිදහස් කර විදුලි ධාරාවක් ඇති කිරීමෙනි. මේ ක්‍රියාව ප්‍රකාශ-වෝල්ටීය බලපෑම ලෙස හැඳින්වේ. නිදහස් වූ ඉලෙක්ට්‍රෝන පැනලයේ පරිපථය හරහා ගලා යන අතර, එම විදුලිය නිවසක උපකරණ ක්‍රියාත්මක කිරීමට හෝ බැටරියක් ආරෝපණය කිරීමට භාවිතා කළ හැක.