PTE听力口语练习-科学60秒-Martian Soil Salts

PTE考生目前最大的问题之一就是练习题缺乏。除了有限的基本官方书(PLUS,Testbuilder, OG)之外,就没有题了。很多英语基础不是很扎实的同学很难找到练习材料。墨尔本文波雅思PTE培训学校专门为墨尔本,悉尼PTE考生准备了适合PTE听力阅读练习的科学60秒。各位PTE同学可以练习PTE听力中的summarise spoken text和PTE口语中的retell lecture,PTE听力口语-科学60秒-Frosty Moss练习记笔记技巧和复述。废话少说,下面开始:

60秒科学:Martian Soil Salts May Make Water Ice All Wet


60秒科学节目(SSS)是科学美国人网站的一套广播栏目,英文名称:Scientific American – 60 Second Science,节目内容以科学报道为主,节目仅一分钟的时间,主要对当今的科学技术新发展作以简明、通俗的介绍,对于科学的发展如何影响人们的生活环境、健康状况及科学技术,提供了大量简明易懂的阐释。

If Martians exist, even the microbial sort, they probably need liquid water. Temperatures on the surface of the red planet are below freezing, but signs exist that water flowed in the past and perhaps still does, thanks to a Martian version of anti-freeze.

Salts lower the freezing point of water, as anyone knows who’s thrown salt on an icy sidewalk. And both NASA’s Phoenix and Curiosity missions found salts called perchlorates sprinkled around the Martian surface.

To see how perchlorates might act on Mars, researchers recreated the pressure, humidity and temperature of the planet inside a metal cylinder. They put a thin layer of perchlorates on top of water ice inside the chamber. Within minutes, droplets of liquid water formed, even at minus 100 degrees Fahrenheit.

Some scientists thought perchlorates might condense water vapor from the atmosphere. But within the cylinder, no liquid water formed in the presence of salts, either alone or on Mars-like soil, unless ice was present too. The study is in the journal Geophysical Research Letters.

The finding study could explain mysterious globules seen on the leg of the Phoenix in 2008. The lander may have been dotted with drops of otherworldly water.


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