首页
登录
职称英语
From Dr. R.S. Scorer of Britain’s Imperial College of Science comes the late
From Dr. R.S. Scorer of Britain’s Imperial College of Science comes the late
游客
2023-09-16
42
管理
问题
From Dr. R.S. Scorer of Britain’s Imperial College of Science comes the latest theory about the cause of lightning flashes. Dr. Scorer believes the cause is hail falling through super-cooled clouds. Ice particles bouncing off the falling hail acquired a positive charge and rise to the top of the cloud while the hail carries a negative charge to the bottom of the cloud.
According to Dr. Scorer, Benjamin Franklin first proved thunderclouds are charged with electricity. Later investigation showed that the tops of the clouds have a great positive charge and the bottoms a great negative charge.
When the charges become great enough to break down the insulating properties of the air, lightning flashes carry the electricity within the cloud, or from cloud to cloud, or from cloud to earth. But the question remained: how do the charges develop within the cloud?
To seek the cause, Dr. Scorer and his colleagues at the college first duplicated thundercloud currents in a liquid tank. They found that mixture takes place only at the tops of the clouds.
Next a study of thunderclouds over the North Atlantic showed that lightning occurs only when the air temperature around the cloud is below freezing. Particles at the top of the cloud begin to freeze but those in the remainder of the cloud stay unfrozen although below freezing temperature.
To measure moisture the scientists sent planes equipped with external refrigerated rods into the clouds. The idea was that moisture would freeze on the rods and could later be measured. The men found, however, that some of the moisture particles bounced off the rods. His accidental discovery set the scientists on a new course of action.
In the laboratory, S.E. Reynolds whirled a refrigerated rod through ice particles and found that the particles which bounced off the rod acquired a positive charge. This was the missing link. Without hail and super-cooled clouds, he concluded, there could be no lightning.
选项
A、law
B、hypothesis
C、guess
D、theory
答案
D
解析
从文章的第一段就可以看出,本文主要介绍一种关于闪电成因的理论,不是规律、假设和猜想。
转载请注明原文地址:http://tihaiku.com/zcyy/3018668.html
相关试题推荐
VisitorstoBritainarealwayscomplainingaboutEnglishfoodbecausetheyrarel
Iamwritingtoyoutotalkabouttakingupoccupationsforcollegegraduates.N
Collegeisaplacetoexploremanypossibilities;youreallycan’tdoitall—
Collegeisaplacetoexploremanypossibilities;youreallycan’tdoitall—
Collegeisaplacetoexploremanypossibilities;youreallycan’tdoitall—
Iamwritingtoyoutotalkabouttakingupoccupationsforcollegegraduates.N
MostofthepeoplewhoarevisitingBritain_____aboutthefoodandweatherthe
[originaltext]M:WelcometoBritain.MayIseeyourpassportandpapers,please
Ingeneral,theapplication--ormisapplication--ofscienceandtechnologyinall
Iamwritingtoyoutotalkabouttakingupoccupationsforcollegegraduates.N
随机试题
PassageTwo[br]WhatcanstudentsgetfromworkingforSeo’scollaborativeproj
Overfivehundredyearsago,amandesigneda(11)machine.Healsoinvente
Theelectionheldyesterdaywas__________(根本不公平).innosensefair
Forthispart,youareallowed30minutestowriteashortessayentitledColleg
6个月婴儿,已诊断为化脓性脑膜炎,经抗生素治疗1周后体温下降,脑脊液白细胞数12
下列关于预期效用理论说法正确的有()。 Ⅰ.预期效用理论又称期望效用函数理论
王阿姨快50岁了,最近单位让她提前退休。但这并非她本人的意愿,对此感到非常焦虑,
计时工资不包括()。A:小时工资制 B:日工资制 C:月度工资制
下列有关行政法的基本原则的说法哪一项是错误的?()A.行政机关作出决定时不得考
男性,66岁,吸烟30年,1包/天,慢性咳嗽、咳痰15年,多为白黏痰,每年发
最新回复
(
0
)