文章 Article
地球？其實是水球——地球日談水資源 Earth Day: The Earth is really a water ball
原發表日期 Originally published：2020-04-21 · PanSci 泛科學
地球日 50 週年主題：全面行動。
Earth Day's 50th anniversary theme: All in Action.
原文轉載泛科學影片的介紹：人類能用的淡水資源只佔很小的比例；影片另介紹逆滲透（RO）的原理。
The original post passed on PanSci's introduction to its video: only a small share of the Earth's water is fresh water people can use; the video also explains how reverse osmosis (RO) works.
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Third-party content: this page gives a summary and a link to the original, not the full text.