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.

Unstring It and It Curls Backward: Why the Korean Gakgung Bow Is Bent the Wrong Way

2026-09-292026-09-30

An unstrung gakgung curls the opposite way until its tips almost touch. Here is how layers of water-buffalo horn, bamboo and ox sinew work together,… Read More »Unstring It and It Curls Backward: Why the Korean Gakgung Bow Is Bent the Wrong Way

How Does a Microwave Oven Heat Food Without Fire?

2026-09-292026-09-29

문이 열린 전자레인지 조리실 안에 유리 회전판이 놓여 있고 오른쪽에 조작 버튼이 있는 모습

A microwave oven heats food by shaking its water molecules with microwaves that oscillate 2.45 billion times per second. See why microwaves reach only about… Read More »How Does a Microwave Oven Heat Food Without Fire?

How Could a Clock Reveal Longitude at Sea?

2026-09-282026-09-28

고리 달린 은색 케이스 안에 로마 숫자 문자판이 보이는 해리슨 H4의 앞면

John Harrison’s marine timekeepers carried reference time across the sea. Explore how time differences reveal longitude, and the experiments from H1 to H4.

Why Can Rain Fall from a Cloud without Wetting the Ground?

2026-09-262026-09-26

Explore virga: precipitation that falls from a cloud without reaching the ground. Learn how evaporation, sublimation and observation height help explain it.

How Does Tapestry Paint Pictures with Thread?

2026-09-242026-09-24

In handwoven tapestry, colored wefts turn back where each color is needed, forming cloth and image together. Explore warp, weft, joins and full-size designs.

Prince Rupert’s Drops: Why Does a Broken Tail Shatter the Strong Head?

2026-09-232026-09-23

A resilient head and fragile tail come from the same cooling process. Real experiments reveal how residual stress shapes a Prince Rupert’s drop.