Southman

I am In Nam, the editor of glu.kr. Under the mission “God Loves U: learn, discuss, and explain all things that God created,” I write across six areas — culture, history, science, plants, animals, and climate. Every article begins as an AI-assisted draft, then goes through source checks, numerical verification, and terminology review before I read and edit it myself for publication. Images carry their source and license, with freely licensed material preferred. If you find an error, write to south-man@daum.net. I verify it, correct the article, and note the change.

How Does a Stone Arch Stand Without a Column in the Middle?

2026-09-142026-09-14

Read the structure of Seungseongyo and Roman aqueducts: how contacting stones, end supports and temporary construction frames make an open arch possible.

Why Does Thunder Keep Rumbling After a Brief Lightning Flash?

2026-09-132026-09-13

Branching lightning above trees and a road near Goldendale, Washington

Thunder does not come only from the ground strike point. Separating channel geometry from repeated strokes explains how a brief flash can be followed by… Read More »Why Does Thunder Keep Rumbling After a Brief Lightning Flash?

How Tree Bark Becomes Hanji: The Different Roles of Fiber and Mucilage

2026-09-102026-09-10

Sheets of hanji in several colors stacked together

Paper mulberry supplies fiber, while dakpul helps control dispersion and drainage. Follow sheet formation, drying, and dochim to see how traditional hanji takes shape.

Does Fog Form Only at Night? Clear Nights, Cold Seas and Warm Water

2026-09-092026-09-09

Radiation, advection and steam fog can look similar but form through different processes. Read fog through air and surface temperatures and the movement of water… Read More »Does Fog Form Only at Night? Clear Nights, Cold Seas and Warm Water

Why Does Indigo Dyeing Need Air to Turn Blue?

2026-09-092026-09-09

염색통 위로 들어 올린 파란 천. 이 사진은 이미 파래진 상태를 보여 준다.

How does water-insoluble indigo color a cloth? Follow reduction in the vat, oxidation in air, and the craft decisions that leave white patterns in blue… Read More »Why Does Indigo Dyeing Need Air to Turn Blue?

The smell of rain is not one smell — three layers, arriving in turn

2026-09-022026-09-02

Raindrops falling on a shallow muddy puddle over reddish-brown soil, leaving overlapping concentric ripples

Distilled water has no smell. And yet we smell rain. What we call “the smell of rain” is not one substance but three separate signals… Read More »The smell of rain is not one smell — three layers, arriving in turn