VOA慢速英语20060110b

SCIENCE IN THE NEWS - Winter Cold: Everything You Ever Wanted to Know About SnowBy George Grow

Broadcast: Tuesday, January 10, 2006

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VOICE ONE:

This is Steve Ember.

VOICE TWO:

And this is Bob Doughty¹ with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell you everything you ever wanted to know about snow.


Woman blowing snowflakes

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VOICE ONE:

Winter weather has returned to northern areas of the world. In much of the United States, winter means the return of snow. Snow is a subject of great interest to weather experts. Experts sometimes have difficulty estimating² where, when or how much snow will fall. One reason is that heavy amounts of snow fall in surprisingly small areas. Another reason is that a small change in temperature can mean the difference between snow and rain.

VOICE TWO:

Snow is a form of frozen⁴ water. It contains many groups of tiny ice particles⁵ called snow crystals⁷. These crystals grow from water particles in cold clouds. They usually grow around a piece of dust. All snow crystals have six sides, but they grow in different shapes. The shape depends mainly on the temperature and water levels in the air.

Snow crystals grow in one of two designs -- platelike and columnar⁸. Platelike crystals are flat. They form when the air temperature is about fifteen degrees below zero Celsius⁹. Columnar snow crystals look like sticks of ice. They form when the temperature is about five degrees below zero Celsius.

VOICE ONE:

The shape of a snow crystal⁶ may change from one form to another as the crystal passes through levels of air with different temperatures. When melting snow crystals or raindrops fall through very cold air, they freeze to form small particles of ice, called sleet¹⁰.

Groups of frozen water droplets¹¹ are called snow pellets. Under some conditions, these particles may grow larger and form solid pieces of ice, or hail¹².

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VOICE TWO:

When snow crystals stick together, they produce snowflakes. Snowflakes come in different sizes. As many as one hundred crystals may join together to form a snowflake larger than two and one-half centimeters. Under some conditions, snowflakes can form that are five centimeters long. Usually, this requires near freezing temperatures, light winds and changing conditions in Earth's atmosphere.

Snow contains much less water than rain. About fifteen centimeters of wet snow has as much water as two and one-half centimeters of rain. About seventy-six centimeters of dry snow equals the water in two and one-half centimeters of rain.

VOICE ONE:

Much of the water we use comes from snow. Melting snow provides water for rivers, electric power centers and agricultural crops. In the western United States, mountain snow provides up to seventy-five percent of all surface water supplies.


Sonepheth and Meggan enjoy the snow in front of their house

Snowfall helps to protect plants and some wild animals from cold, winter weather. Fresh snow is made largely¹³ of air trapped among the snow crystals. Because the air has trouble moving, the movement of heat is greatly reduced.

Snow also is known to influence the movement of sound waves. When there is fresh snow on the ground, the surface of the snow takes in, or absorbs, sound waves. However, snow can become hard and flat as it becomes older or if there have been strong winds. Then the snow's surface will help to send back sound waves. Under these conditions, sounds may seem clearer and travel farther¹⁴.

VOICE TWO:

Generally, the color of snow and ice appears white. This is because the light we see from the sun is white. Most natural materials take in some sunlight. This gives them their color. However, when light travels from air to snow, some light is sent back, or reflected. Snow crystals have many surfaces to reflect sunlight. Yet the snow does take in a little sunlight. It is this light that gives snow its white appearance.

Sometimes, snow or ice may appear to be blue. The blue light is the product of a long travel path through the snow or ice. In simple terms, think of snow or ice as a filter¹⁵. A filter is designed to reject some substances, while permitting others to pass through. In the case of snow, all the light makes it through if the snow is only a centimeter thick. If it is a meter or more thick, however, blue light often can be seen.

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VOICE ONE:

Snow falls in extreme northern and southern areas of the world throughout the year. However, the heaviest snowfalls have been reported in the mountains of other areas during winter. These areas include the Alps in Italy and Switzerland, the coastal¹⁶ mountains of western Canada, and the Sierra Nevada and Rocky Mountains in the United States. In warmer climates, snow is known to fall in areas over four thousand nine hundred meters above sea level.

VOICE TWO:

Each year, the continental¹⁷ United States has an average of one hundred snowstorms¹⁹. An average storm produces snow for two to five days. Almost every part of the country has received snowfall at one time or another. Even parts of southern Florida have reported a few snowflakes.

The national record for snowfall in a single season was set in nineteen ninety-eight and nineteen ninety-nine. Two thousand eight hundred ninety-five centimeters of snow fell at the Mount³ Baker²⁰ Ski area in the northwestern state of Washington.

VOICE ONE:

People in many other areas have little or no snowfall. In nineteen thirty-six, a physicist²¹ from Japan produced the first man-made snow in a laboratory²². During the nineteen-forties, several American scientists developed methods for making snow in other areas. Clouds with extremely cool water are mixed with man-made ice crystals, such as silver iodide and metaldehyde crystals. Sometimes, dry ice particles or liquid propane are used. Today, special machines are used to produce limited amounts of snow for winter holiday ski areas.

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VOICE TWO:

Snow is responsible for the deaths of hundreds of people in the United States every year. Many people die in traffic accidents on roads that are covered with snow or ice. Others die from being out in the cold or from heart attacks caused by extreme physical activity.

A few years ago, a major storm caused serious problems in the eastern United States. It struck the Southeast in January ninety ninety-six, before moving up the East Coast. The storm was blamed for more than one hundred deaths. It forced nine states to declare emergency measures.

Virginia and West Virginia were hit hardest. In some areas there, snowfall amounts were more than one meter high. Several states limited driving to emergency vehicles. Most major airports were closed for at least a day or two.

A week later, two other storms brought additional²³ snow to the East Coast. In the New York City area, the added weight of the snow forced the tops of some buildings to break down. Many travelers were forced to walk long distances through deep snow to get to train stations.

VOICE ONE:

People may not be able to avoid living in areas where it snows often. However, they can avoid becoming victims of winter snowstorms.


Commuters wait for a bus on elegant²⁴ Nowy Swiat Street in Warsaw, Poland

People should stay in their homes until the storm has passed. While removing large amounts of snow, they should stop and rest often.

Difficult physical activity during snow removal²⁵ can cause a heart attack. It is always a good idea to keep a lot of necessary supplies in the home even before winter begins. These supplies include food, medicine, clean water, and extra power supplies.

VOICE TWO:

Some drivers have become trapped in their vehicles during a snowstorm¹⁸. If this happens, people should remain in or near their car unless they see some kind of help. They should get out and clear space around the vehicle to prevent the possibility of carbon monoxide gas poisoning.

People should tie a bright-colored object to the top of their car to increase the chance of rescue. Inside the car, they should open a window a little for fresh air and turn on the engine for ten or fifteen minutes every hour for heat.

People living in areas where winter storms are likely should carry emergency supplies in their vehicle. These include food, emergency medical supplies, and extra clothing to stay warm and dry. People in these areas should always be prepared for winter emergencies. Snow can be beautiful to look at, but it can also be dangerous.

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VOICE ONE:

This SCIENCE IN THE NEWS program was written by George Grow. Our producer was Cynthia Kirk. This is Steve Ember.

VOICE TWO:

And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.

1 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

2 estimating   

n.估计v.估计，评价，评估( estimate的现在分词 )；（粗略）估计（…的距离、价值、数目、大小、重量、费用等），估量，预算

参考例句：

• We use nonparametric tests, we lose sharpness in estimating intervals. 使用非常数检验我们失掉了估计区间的灵敏性。 来自辞典例句
• CA986 from San Francisco is estimating in at 22:25. 从旧金山飞来的CA986航班估计22点25分到达。 来自辞典例句

3 mount   

n.山峰，乘用马，框，衬纸；vi.增长，骑上（马）；vt.提升，爬上，装备

参考例句：

• Their debts continued to mount up.他们的债务不断增加。
• She is the first woman who steps on the top of Mount Jolmo Lungma.她是第一个登上珠穆朗玛峰的女人。

4 frozen   

adj.冻结的，冰冻的

参考例句：

• He was frozen to death on a snowing night.在一个风雪的晚上，他被冻死了。
• The weather is cold and the ground is frozen.天寒地冻。

5 particles   

微粒( particle的名词复数 )； 颗粒； 极少量； 小品词

参考例句：

• These small particles agglomerate together to form larger clusters. 这些颗粒聚结形成较大的团。
• The nucleus of an atom consists of neutrons, protons and other particles. 原子核由中子、质子和其他粒子构成。

6 crystal   

n.水晶，水晶饰品，结晶体；最好的玻璃器皿

参考例句：

• It used to be a crystal stream.那曾是条清澈见底的小溪。
• Those fine wine glasses are made of crystal.那些漂亮的酒杯是用水晶做的。

7 crystals   

n.水晶( crystal的名词复数 )；结晶（体）

参考例句：

• It is snow and ice crystals. 这是雪和冰的结晶体。 来自《简明英汉词典》
• Snowflakes are loose aggregates of ice crystals. 雪花是冰晶的松散凝结。 来自《简明英汉词典》

8 columnar   

adj.柱形的，筒形的，分纵栏印刷或书写的

参考例句：

• Snow crystals grow in one of two designs—platelike and columnar. 雪晶是按照两种形状中的一种——板状和圆柱形形成的。 来自辞典例句
• Simple columnar epithelium consists of tall, narrow cells having considerably greater height than width. 单层柱状上皮由高桂状上皮细胞组成，细胞的高度显著大于细胞的宽度。 来自辞典例句

9 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

10 sleet   

n.雨雪；v.下雨雪，下冰雹

参考例句：

• There was a great deal of sleet last night.昨夜雨夹雪下得真大。
• When winter comes,we get sleet and frost.冬天来到时我们这儿会有雨夹雪和霜冻。

11 droplets   

n.小滴( droplet的名词复数 )

参考例句：

• Droplets of sweat were welling up on his forehead. 他额头上冒出了滴滴汗珠。 来自辞典例句
• In constrast, exhaled smoke contains relatively large water droplets and appears white. 相反，从人嘴里呼出的烟则包含相当大的水滴，所以呈白色。 来自辞典例句

12 hail   

n.雹，一阵；vi.下雹；vt.高呼，为...喝彩

参考例句：

• Hail fell with such violence that it broke windows.冰雹猛落，把玻璃窗也砸破了。
• The people lined the streets to hail the returning heroes.人们夹道欢迎凯旋的英雄们。

13 largely   

adv.大部分，主要地

参考例句：

• It is largely dependent on the weather.这多半取决于天气情况。
• Their conclusions were largely founded on guesswork.他们的结论大部份基于猜测。

14 farther   

adj.更远的，进一步的；adv.更远的，此外；far的比较级

参考例句：

• I can throw the ball farther than you can.这个球我能比你扔得远。
• The farther hill is five kilometres away.那座更远的小山在五公里以外。

15 filter   

n.滤器，过滤嘴；v.过滤，透过

参考例句：

• Foreign influence began to filter into the country.外国势力开始渗透进这个国家。
• Charcoal is used to filter water.木炭是用来过滤水的。

16 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

17 continental   

adj.大陆的，大陆性的，欧洲大陆的

参考例句：

• A continental climate is different from an insular one.大陆性气候不同于岛屿气候。
• The most ancient parts of the continental crust are 4000 million years old.大陆地壳最古老的部分有40亿年历史。

18 snowstorm   

n.雪暴，暴风雪

参考例句：

• After several weeks of travel,snowstorm hit us first.我们旅行了几个星期，初次碰上了暴风雪。
• A severe snowstorm blocked up railroads.一场暴风雪使铁路中断。

19 snowstorms   

n.暴风雪，雪崩( snowstorm的名词复数 )

参考例句：

• However, they can avoid becoming victims of winter snowstorms. 但是，他们有能力避免成为冬季暴风雪的牺牲品。 来自互联网
• Snowstorms played hell with the flow of city traffic. 暴风雪严重地影响了市内交通。 来自互联网

20 baker   

n.面包师

参考例句：

• The baker bakes his bread in the bakery.面包师在面包房内烤面包。
• The baker frosted the cake with a mixture of sugar and whites of eggs.面包师在蛋糕上撒了一层白糖和蛋清的混合料。

21 physicist   

n.物理学家，研究物理学的人

参考例句：

• He is a physicist of the first rank.他是一流的物理学家。
• The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。

22 laboratory   

n.实验室，化验室

参考例句：

• She has donated money to establish a laboratory.她捐款成立了一个实验室。
• Our laboratory equipment isn't perfect,but we must make do.实验室设备是不够理想，但我们只好因陋就简。

23 additional   

adj.添加的，额外的，另外的

参考例句：

• It is necessary to set down these additional rules.有必要制定这些补充规则。
• I think we can fit in an additional room.我想我们可以再加建一间房子。

24 elegant   

adj.优美的，文雅的，简练的，简结的

参考例句：

• She was an elegant and accomplished woman.她是位优雅的才女。
• She has a life of elegant ease.她过着风雅悠闲的生活。

25 removal   

n.去除，消除；挪走，移走，搬迁

参考例句：

• After the removal of the soup,fish was served.汤撤去后，鱼就上来了。
• The factory announced its removal to another town.这家工厂宣布迁往另一座城镇。