粉末铁心

SSS 2008-06-04

This is Scientific American's 60-Second Science, I am Cynthia Graber.This'll just take a minute. On earth, snow crystals as we all know, form from frozen water. But scientists believe there're also flakes that fall on Mercury, and they're made of iro

发表于:2019-01-07 / 阅读(53) / 评论(0)

Scientific American(六)月

SSS 2011-09-08

This is Scientific Americans 60-Second Science. Im Karen Hopkin. This will just take a minute. Thars gold in them thar hillsand we may have meteorites to thank. Because it appears that a rain of meteors nearly 4 billion years ago peppered the Earths

发表于:2019-01-08 / 阅读(67) / 评论(0)

Scientific American(九)月

VOA标准英语2011--Micronutrient Powders Effective in Reduc

Micronutrient Powders Effective in Reducing Anemia in Children Nutrients taken in powder form are effective in preventing malnutrition in children, according to new findings. Children throughout the developing world suffer from anemia - a shortage of

发表于:2019-01-13 / 阅读(64) / 评论(0)

VOA标准英语2011年(九月)

英语听力：自然百科穿越银河系的旅行 Through Milky Way—11

Once theyve caught the light of a dying star with their state of our telescopes. The detective work can begin. We collect that light and we analyze it in great detail in order to determine whats going on, whats the chemical makeup of the star, whats

发表于:2019-01-22 / 阅读(41) / 评论(0)

自然百科2011年

英语听力：自然百科地球力场 Earth's Force Field—7

The loss of the magnetic field has a catastrophic impact on the planet's evolution. Mars becomes the red planet we see today. If earths magnetic protection continues to fade, would it suffer the same fate? If it vanishes completely, the planet might

发表于:2019-01-22 / 阅读(56) / 评论(0)

自然百科2011年

英语听力：自然百科地球力场 Earth's Force Field—8

Easily confused by this idea, there has a big thawed iron inner core, so that I think it's just the bar magnet, just permanent magnet frozen in nad, and that's where causes all the magnetic field. But it's too hot inside the Earth, that can't happen

发表于:2019-01-22 / 阅读(46) / 评论(0)

自然百科2011年

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