Bartosz Ciechanowski
Long, hands-on explainers on how watches, bikes, GPS, sound and the Moon work — every diagram is a 3D model you can spin and tweak with sliders.
What it is
The personal site of Bartosz Ciechanowski, an engineer who writes extremely thorough explainers about how everyday things work. Mechanical watches, internal combustion engines, gears, cameras and lenses, GPS, sound, airfoils, bicycles — and most recently the Moon, published in December 2024. Nearly every illustration is a live 3D model: drag to rotate it, and use the sliders underneath to change speed, angle or time of day.
Why we picked it
New pieces arrive maybe once a year, and you can see why. Each one is less a blog post than a small interactive textbook. In the watch article you assemble the movement part by part and see exactly what each wheel is for. The GPS piece starts you with one satellite, then adds more until the whole idea clicks, without drowning you in equations. You learn by poking at things, which is why it sticks. There are no ads; the work is funded by readers on Patreon.
Where to start
- "Mechanical Watch" — the most famous piece and a natural first read.
- "GPS" — if you've ever wondered how your phone knows where you are.
- "Sound" — waves, pressure, and why you can hear anything at all.
- "Moon" — the latest essay, with a Moon model you can scrub through dates and times.
- The Archives page — the full list with dates, from early coding posts to the physics era.
Who it's for
Anyone who never quite clicked with physics at school and would like a second go. Engineers, designers and teachers looking for proof of how good an explanation on the web can be. Curious teenagers who are comfortable with long reads in English. Use a laptop or desktop if you can: the models are heavy and each article is a good hour of reading.
Quick answers
Is it free? Yes, every article is open to read. You can support the author on Patreon.
How often are new articles published? Rarely — the archive shows one to three a year, the latest being "Moon" from December 2024.
Does it work on a phone? The articles open on mobile, but the 3D models are much easier to handle with a mouse on a bigger screen.
