HowItActuallyWorks
Everyday mechanisms, explained with sources. One diagram, one myth checked, every week. Wrong? We correct it publicly.
Columns
- One Mechanism, One Diagram — One everyday mechanism, explained with one self-made diagram.
- MythCheck — A common claim, checked against evidence, with a clear verdict.
- Monthly Curiosity Archive — A monthly index of that month's posts, with a short review.
Pinned Manifesto Thread
Sources — Tidal Locking: Why the Moon Always Shows the Same Face
Post: Tidal Locking thread, post 1 (with diagram) · post 2
Sources — Airplane Windows: Why Are Airplane Windows Round?
Post: Airplane Windows thread, post 1 (with diagram) · post 2 · post 3
Sources — Water Molecules: How Many Water Molecules Are in a Glass of Water?
Post: Water Molecules post (with diagram)
- Water molar mass ≈ 18.015 g/mol; Avogadro constant exactly 6.02214076×10^23 /mol (SI definition). Calculation: 250 g / 18.015 g per mol ≈ 13.88 mol; 13.88 × 6.02214076×10^23 ≈ 8.36×10^24, stated as about 8×10^24. 250 g is a typical glass; a smaller glass gives a smaller count.
Sources — MSG: Is MSG Actually Harmful?
Post: MSG thread, post 1 (with diagram) · post 2
- FDA — Questions and Answers on Monosodium glutamate (MSG): supports that added MSG is “generally recognized as safe”; in studies with self-identified sensitive individuals given MSG or a placebo, scientists have not been able to consistently trigger reactions; a typical serving of a food with added MSG contains less than 0.5 g, while the mild, short-lived symptoms noted by FASEB were tied to 3 g or more consumed without food.
Sources — Mercator Projection: Why Greenland Looks as Big as Africa on Maps
Post: Mercator thread, post 1 (with diagram) · post 2
- CIA World Factbook — Greenland: supports Greenland total area 2,166,086 sq km (stated in the thread as about 2.17 million km2).
- Encyclopaedia Britannica — Africa: supports Africa total land area approximately 30,365,000 sq km (stated in the thread as about 30.4 million km2); the ratio 30,365,000 / 2,166,086 ≈ 14.02 is calculated from these two figures and stated as about 14 times.
- Encyclopaedia Britannica — Mercator projection: supports the mechanism that the Mercator projection is conformal (preserves local angles), was designed for navigation, and distorts area increasingly toward the poles.
Sources — Goosebumps: Why Do You Get Goosebumps?
Post: Goosebumps thread, post 1 (with diagram) · post 2
- Encyclopaedia Britannica — Arrector pili: supports that arrector pili are small muscles attached to hair follicles, whose contraction makes hair erect and creates the bump, as an involuntary sympathetic reflex triggered by cold, shock or fright.
- NIH Research Matters — What goosebumps are for: supports that tiny arrector pili muscles pull hair upright, that thick fur helps animals keep warm, and that this does not do so for people.
- Cleveland Clinic Health Essentials — Why Do You Get Goosebumps?: supports that goosebumps are an involuntary sympathetic (fight-or-flight) reaction, triggered by cold, fear, shock, anger, excitement, and frisson from music, movies, ASMR or speeches.
Sources — Ancient Timekeeping: How Did People Tell Time Before Clocks?
Post: Ancient Timekeeping thread, post 1 (with diagram) · post 2
- Encyclopaedia Britannica — Sundial: supports that a sundial indicates the time of day by the position of the shadow of an object exposed to the Sun's rays, and that the shadow moves as the Sun moves across the sky.
- Encyclopaedia Britannica — Clepsydra: supports that a water clock measures time by the gradual flow of water, that it complemented Sun-based methods, that it could measure time indoors and under overcast skies, and that in one form time was read from graduated lines measuring the remaining water level.
Corrections Log
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Correction format: Correction: original post date, original claim, what was wrong, corrected claim, and source. Original posts are not deleted for corrections; the correction is posted publicly and linked.