On Taskmaster, Tim Vine tried to chain drinking straws together to try and blow out a candle through them. He couldn't do it — no matter how hard he blew, the candle stayed lit. Moments later, a garden hose of triple the length did the job with no effort at all. Longer length, same idea, wildly different result, and the reason isn't obvious until you actually work through the physics: resistance to flow scales with the fourth power of the tube's radius, so a straw's narrowness matters far more than its length ever could.
Hagen–Poiseuille
ΔP=
8μLQ
πr4
That gag is the reason this site exists. The equation behind it (Hagen–Poiseuille flow) is genuinely not intuitive from the numbers alone — but it's obvious the moment you can drag a slider and watch a straw and a hose fight the same rule in real time. That first page I created, Why the straw gives up, and it set the format for everything since: one real question, real numbers, real equations, a few controls and an animated chart instead of a wall of text explaining what would happen if you did.
Every page since has followed the same shape — pick a concept that's usually hidden inside a formula or a big number, find the smallest interactive figure that makes it click, and be honest on the page about any approximation being made.
Cantilever, point load
Drag the load along the beam.
I'm Simon, and by training I'm a civil engineer — the kind of work where a beam's load, its deflection, and its safety factor all have to agree with each other before anything gets built. These days I work on data visualization for building energy efficiency instead of load calculations, but the habit is the same one this site runs on: a formula only means something once you can watch it move.
The site itself is designed and maintained by me, built with AI-assisted development — I'm not a professional web developer, just someone who wanted these ideas to exist as pages you can play with instead of paragraphs you have to read. If something's unclear, wrong, or you have an idea for a concept worth adding, write to [email protected] — or leave private feedback directly on any page.
The goal is simple: visually explain or demonstrate physics and mathematical models, so people (myself included) can enjoy learning or re-learning about the awesome world around us.