Why Salt Clump s 为什么盐会结块? You probably noticed that sometimes the salt gets clump y . If its really humid outsidethere may even be condensation on top of the salt shaker. The reason this happens is that salt is hygroscopic . Hygroscop

发表于:2019-01-26 / 阅读(65) / 评论(0) 分类 英语听力文摘 English Digest

Long Live Us About a century ago, the average life-span for Americans was about 50 years. Today, the typical American lives for around seventy-eight years. According to a German aging study, the maximum life span in industrialized countries has incre

发表于:2019-01-26 / 阅读(55) / 评论(0) 分类 英语听力文摘 English Digest

The title track of Black Rose's newest CD, is called Sky Stamp. It opens with a traditional Mongolian long-song: This is the music of vast open spaces and big blue skies. It is the music of Mongolian nomads, calling out across the grasslands, soothin

发表于:2018-12-31 / 阅读(57) / 评论(0) 分类 英语听力文摘 English Digest

Why Do Golf Balls Have Dimples? Youre out on the golf course one pleasant afternoon. Your ball is set on the tee. You lean over the ball. You grip the club just right. Your arms are straight. Your stance perfect. Whoosh! You swing, and the ball takes

发表于:2018-12-31 / 阅读(53) / 评论(0) 分类 英语听力文摘 English Digest

Do Magic Mushrooms Make People Nicer? Ive heard that psilocybin, which is the hallucinogenic ingredient in psychedelic mushrooms, can alter peoples personalities and make them nicer. Is that true? Well, first, before answering the question, we need t

发表于:2018-12-31 / 阅读(71) / 评论(0) 分类 英语听力文摘 English Digest

Night Vision And Humans: Why Cant We See Color? When we are in a fairly dark room, or outside at night away from lights, we can still see, but we cant see the colors of things very well. Why is that? There are two kinds of light-sensitive organs loca

发表于:2018-12-31 / 阅读(80) / 评论(0) 分类 英语听力文摘 English Digest

When Continents Collide: The History Of Our Planet It was one of the Earths momentous times. Continents collided. Volcanoes erupted. Ocean currents shifted. Species ran amok. Twenty million years ago, North and South America were arranged in nearly t

发表于:2018-12-31 / 阅读(57) / 评论(0) 分类 英语听力文摘 English Digest

Why The Sky Is Not Blue Look at various parts of the sky on a clear day and you will see that it is not a uniform blue. Even if the sky is deep blue when you look straight up, near the horizon it is lighter. This is partly due to pollution, but even

发表于:2018-12-31 / 阅读(61) / 评论(0) 分类 英语听力文摘 English Digest

The Blurry World Underwater When you open your eyes underwater, things look blurry, but with goggles, everything looks perfectly clear. Why cant we landlubbers focus underwater without goggles? First, we need to explore how our eyes focus when were h

发表于:2018-12-31 / 阅读(92) / 评论(0) 分类 英语听力文摘 English Digest

The Rolling Boil That Cools Your Food When you think of something boiling, you probably picture a pot on the stove, but theres another kitchen appliance that brings liquid to a boil, not to heat food, but cool it. It sounds crazy, but household refri

发表于:2018-12-31 / 阅读(90) / 评论(0) 分类 英语听力文摘 English Digest

Why refrigerators hum? Why refrigerators hum,on toay's moment of science.On the recent program we have discussed how fluorocarboncoolant cools your food by coming to a boil in coils hidden in your fridge. How is this possible? When you boil water o

发表于:2018-12-31 / 阅读(80) / 评论(0) 分类 英语听力文摘 English Digest

Sometime Cavemen From the bestselling novel Clan of the Cave Bear to the 1981 movie Caveman, pop-culture tends to misrepresent prehistoric people as cave dwelling brutes. But even the most speculative recreations of early human society are based on a

发表于:2018-12-31 / 阅读(55) / 评论(0) 分类 英语听力文摘 English Digest

Secrets Of Silk Production Fifteen hundred years ago in China, silk production was a state secret. The silk trade was so valuable that anyone who tried to take silkworm eggs or mulberry seeds out of China was put to death. Then in 552 AD, two monks s

发表于:2018-12-31 / 阅读(51) / 评论(0) 分类 英语听力文摘 English Digest

Survival Of The Sluggish Silkworms have been bred over thousands of years to behave quite unlike their caterpillar cousins in the wild. Thats because people purposely breed silkworms to fit this job description: WANTEDSuperlative silk producers. Bene

发表于:2018-12-31 / 阅读(58) / 评论(0) 分类 英语听力文摘 English Digest

The Mathematics Of Middle-Age Spread Lets say youre an 18 year old male who runs every other day, logging 12 miles a week. Now fast-forward to your late 40s. Your eating habits are the same. To maintain your high school weight, how many miles a week

发表于:2018-12-31 / 阅读(52) / 评论(0) 分类 英语听力文摘 English Digest

Why Do Zebras Have Stripes? For many animals, camouflage is an important part of survival. A leopards spotted coat and a polar bears white fur help them blend into their respective environments. But a zebras bold stripes cant help to disguise it in i

发表于:2018-12-31 / 阅读(48) / 评论(0) 分类 英语听力文摘 English Digest

How Neanderthals Fought Disease Every year people are encouraged to get their annual flu shots. Signs are posted at drug stores and clinics. Get your shots here. Modern preventive medicine has saved millions of lives. But you may be surprised to hear

发表于:2018-12-31 / 阅读(49) / 评论(0) 分类 英语听力文摘 English Digest

Freeze Suppose you are an animal. Well, actually, you are an animal, but suppose youre another kind of animal, maybe something small that might make a tasty snack for a larger predator. Youre walking along one day when you see a big dog. What do you

发表于:2018-12-31 / 阅读(77) / 评论(0) 分类 英语听力文摘 English Digest

In the 1960s, during the earliest space flights, no one knew exactly how weightlessness would affect eating and drinking. Would food fly off a plate? Would astronauts have digestive problems, with no gravity to help things along the digestive system?

发表于:2018-12-31 / 阅读(69) / 评论(0) 分类 英语听力文摘 English Digest

It may sound silly, but its really a good question, because weightlessness does make a visit to the latrine a tricky proposition. Weightlessness poses two main problems in the bathroom. The first is that an astronaut could drift away from the bowl at

发表于:2018-12-31 / 阅读(64) / 评论(0) 分类 英语听力文摘 English Digest