海水为什么是咸的? 大家都会說,因为海水里面含有鹽分。但是,海水里面的鹽分从那里來的呢? 关於海水里的鹽分的來源,一般有兩种說法。有的人說,海水里的鹽分主要是由陸地上的河流帶到海里去的。可是我們知道,河水几乎完全沒有咸味,为甚么說海里的鹽是由河水帶進去的呢?原來河水虽然几乎完全沒有咸味,里面却含有由陸地溶解進去的微量鹽分。河水流到海里,虽然可以把海水冲淡,但是因为海水受到陽光照射的影响,便不断地蒸發成为水蒸汽上升到天空,而把鹽分留在海里,有人做过这样的計算,每年全世界的河流流到海里的水大約有三十万億噸,而河水里鹽分的含量大約是万分之一,因此由於河流带往海里的鹽分每年就有三十億噸上下。空中的水蒸汽遇到冷,又凝結成为雨雪降到陸 Why is seawater salty? Everyone will say because seawater contains salt. However, where does the salinity in seawater come from? There are two general arguments about the source of salinity in seawater. Some people say that the salt in the sea is mainly brought to the sea by rivers on the land. However, we know that the river is almost completely salt-free. Why is the salt in the sea brought in by the river? The original river water, though almost completely salt-free, contains trace amounts of salt dissolved in the land. The river flows into the sea, although it can dilute the seawater, but because the seawater is affected by sunlight, it continuously evaporates into water vapor and rises to the sky, leaving salt in the sea, and some people have done such calculations every year. The amount of water flowing into the sea is about 30 trillion tons, and the salt content in the river is about one ten-thousandth of a million. Therefore, the annual salt content brought by the river to the sea is about 3 billion tons. The water vapor in the air encounters coldness and condenses into rain and snow.