首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Rainmaking 1 The idea of rainmaking is almost as old as man, but it was not until 1946 that man succeeded in making rain. In anc
Rainmaking 1 The idea of rainmaking is almost as old as man, but it was not until 1946 that man succeeded in making rain. In anc
admin
2012-07-29
38
问题
Rainmaking
1 The idea of rainmaking is almost as old as man, but it was not until 1946 that man succeeded in making rain. In ancient times, rainmakers had claimed to bring rain by many methods: dancing singing, killing animals (including humans).
2 For a long time, men have understood where rain comes from. Water from the surface of oceans and lakes becomes part of the air, where it forms clouds from which rain falls. But exactly what starts the formation of raindrops was not known until quite recently. A man named John Aitken proved that drops of water gather around tiny bits of dust or other matter. The centers of the drops are so small that the human eye cannot see them. Without such centers, it seems raindrops do not form.
3 During World War II , Dr. Irving Langmir, and his assistant Schaefer, were hired by the General Electric Company to study how and why ice forms on the wings of airplanes. They went to a mountain in New Hampshire, where snowstorms are common and cold winds blow. They were surprised to find that often the temperature of the clouds surrounding them was far below the freezing point, and yet ice did not form in the clouds.
4 After the War, Schaefer experimented with a machine that created cold, moist air similar to the air found in clouds. To imitate the moist air of a cloud. Schaefer would breathe into the machine. Then he would drop into the freezer a bit of powder , sugar , or some other substance. For weeks and months he tried everything he could imagine. Nothing happened. No crystals of ice were formed. None of the substances would serve as the center of a snow crystal or raindrops.
5 One July morning, Schaefer was dropping in bits of various substances and watching the unsuccessful results. Finally, a friend suggested that they go to eat lunch and Schaefer went with him. As usual, he left the cover of the freezer up, since cold air sinks and would not escape from the box.
6 Returning from lunch, Schaefer found that the temperature of the freezer had risen to a point higher than that required for ice crystals to remain solid. There were two choices now. He could close the cover and wait for the freezer itself to lower the air temperature, or he could make the process occur faster by adding dry ice a gas in solid form that is very, very cold. He chose the latter plan. As he dropped the steaming white dry ice into the freezer, he happened to breathe out a large amount of air. And there, before his eyes, it happened! He had made ice crystals, not by adding centers to the moisture, but by cooling the breath so much that the liquid had to form crystals! Then he began to blow his breath into the freezer and drop large pieces of dry ice through it to create crystals which became a tiny snowstorm falling slowly to the floor of his laboratory.
7 After planning carefully, Schaefer made an experiment by dropping dry ice from his plane to the clouds below him. As was expected, snow formed and fell from the bottom of the cloud. Schaefer succeeded. He made history.
A Langmir and Schaefer’s work for the GE Company
B Langmir and Schaefer’s discovery of rain-forming
C Men’s knowledge of rain-forming
D Schaefer’s several unsuccessful experiments
E Schaefer’s discovery by accident
F Langmir and Schaefer’s successful cooperation
Paragraph ______
选项
答案
D
解析
本段描述了Schaefer从事的人工制造冰晶体的实验,但没有成功。
转载请注明原文地址:https://kaotiyun.com/show/Lmmd777K
本试题收录于:
职称英语卫生类B级题库职称英语分类
0
职称英语卫生类B级
职称英语
相关试题推荐
Youwillheartwoconversations.Writedownonewordornumberinthenumberedspacesontheformsbelow.CONVERSATION1(Que
Youwillheartwoconversations.Writedownonewordornumberinthenumberedspacesontheformsbelow.CONVERSATION1(Que
Lookatthetenstatementsforthispart.Youwillhearamantalkingabout"TheWrightBrothers".Decidewhetheryout
Lookatthetenstatementsforthispart.Youwillhearamantalkingabout"TheWrightBrothers".Decidewhetheryout
Lisathinksyoucanenjoyaholidaywithoutspendingalot.Benhasarrangedtogoonaseasideholiday.
AtpresentinChinatheTBinfectionrateWhichofthefollowingisNOTmentionedinthepassageasafactormakingtheruralT
Sulphurhasoccasionallybeenfoundintheearthinanalmostpurestate.
MyExperienceaboutEnglishOnesummernight,onmywayhomefromworkIdecidedtoseeamovie.Iknewthetheatrewouldbeair
A.Whatcausesautism?B.Howcommonisautism?C.Doesautismoccurtogetherwithotherdisabilities?D.Whatisthedifference
Whenaliquidboils,itbecomesagas.
随机试题
锥体束损害时最易引出的病理反射是:()
2%碘酊消毒皮肤后,再用75%酒精脱碘需间隔的时间是
下列除哪项外,均是胞宫的别称
A、增生性菜花状溃疡B、唇周皮肤先有红斑,随后出现密集小水疱C、口腔病损呈多形性改变如红斑、水疱、糜烂、渗出等,皮肤有虹膜状红斑D、充血糜烂面上覆灰黄色膜E、散在圆形或椭圆形溃疡,溃疡中央凹陷、周围有狭窄红晕,疼痛明显药物变态反应性口炎的临床表现特点是
磁粉检测根据磁化试件的方法可分为()。
井筒砌壁模板中,采用液压动力脱模的是()。
旅行社法定代表人变更,应当()。
我国1922年颁布的“壬戌学制”实行的是()。
在本次学术座谈会中,张嘉、莫非、刘涛应邀出席并都受到主席的嘉奖记功,记功分为一等功、二等功、三等功。三人均对受到的记功闭口不言,但神通广大的记者仍对三人的获奖情况找到了蛛丝马迹.据悉最终的嘉奖记功符合以下条件:(1)如果张嘉记二等功,则莫非记三等功;(
A、Becausewearenotsogood.B、Becauseweareimposters.C、Becauseweareself-abandoned.D、Becauseweareafraidtoknowthem.
最新回复
(
0
)