The science of light, taught from first principles.
A growing library on physics optics — ray tracing, wave behavior, quantum phenomena, and the instruments that bend light to our will. Written for students, teachers, and the merely curious.
First-principles
Every article derives the math from scratch — no hand-waving past the interesting bits.
Ray + wave + photon
Three lenses on the same phenomena. Pick the level of abstraction you need.
Numerical worked examples
Calculations you can plug into your own derivations or test in the lab.
Open notebooks
Every diagram and simulation has reproducible code. Use it, fork it, share it.
The latest deep dive.
The most recent long-form treatment from our archive of optics.
Fun Facts About Light: 25 Interesting Things You Didn't Know
Light is stranger than it looks. It is the fastest thing there is, the Sun's light reaches you eight minutes old, and your eyes are photon detectors. Here are 25 fun facts about light, each one true and explained in a line.
Explore by category.
Every article is filed under a topic. Pick a category to dive into the science of light at the level you need.
What we've published lately.
How Do Blue Light Glasses Work? The Science Behind Them
Blue light glasses promise to save your eyes from screens. The optics are real — a tint or coating does filter some blue light — but the evidence on what that actually does is more surprising. Here's the honest science.
How Does a Light Bulb Work? (Incandescent, LED & Smart)
Flip a switch and a room floods with light — but the bulb doing it might work in one of three completely different ways. Here's how incandescent, LED, and smart light bulbs actually turn electricity into light.
How Does a Light Switch Work? (Mechanical & Electronic)
A light switch does one deceptively simple job: it completes or breaks the loop of wire that feeds your bulb. Here's exactly how that works — from a basic one-way switch to two-way, dimmer, and smart switches.
How Does a Lighter Work? (Flint, Butane & Electric)
One flick and you have fire on demand. Behind that small flame is a neat bit of chemistry and physics — a spark, a stream of fuel, and a flame. Here's how flint, butane, and electric arc lighters actually work.
How Is Light Measured? Units, Tools and Examples
Light is measured in more ways than you'd think — total output in lumens, brightness on a surface in lux, beam intensity in candela, and colour in kelvin. Here are the 6 key units, the tools that read them, and real-world examples.
How Was Light Made? The Origin of Light in the Universe
Light wasn't always free to travel. It was forged in the fire of the Big Bang, trapped for nearly 400,000 years, then released across the whole universe at once. Here's the story of how light was made — in three acts.