Tiny effects, computed in the open.

Every entry takes one very small difference, works it out from stated constants, and hands you the sliders.

The house position: a small number with its assumptions hidden is a rumor. Here each assumption is a control you can move, each constant has a source, and where the quick formula and the careful one disagree, we say by how much.

Where the shortcut breaks: the entries ranked by how far each quick formula can be pushed, with a tolerance slider.

Entries

• The top floor runs fast: what a skyscraper does to your clock, and where the textbook shortcut breaks
• One day off: how long a leap-year rule lasts, and why the best rules' answers are mostly uncertainty
• The seconds pendulum: a metre of string, and which of place, height and swing costs the most seconds a day