全部书籍

专业

应用 关于 Coach 登录 开始阅读

书籍暂未推出简体中文版——当前显示英文版。

Physics · 术语表

什么是 Sundial?

Definition 18.4 Primary & Middle School Physics · 第 18 章 — The Sun in the Sky: Days and Seasons

A sundial is a clock made of a shadow: a stick or blade standing in the sun, with marks around it showing where the shadow falls at each hour. As the Sun travels its arc, the shadow sweeps around the marks — slowly, silently, and without a single moving part.

在原文中阅读 →