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
2024-06-15
33
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:https://www.tihaiku.com/zcyy/3634934.html
相关试题推荐
[originaltext]Ifyoufeeloverwhelmedbyyourcollegeexperience,youaren
[originaltext]Ifyoufeeloverwhelmedbyyourcollegeexperience,youaren
[originaltext]Ifyoufeeloverwhelmedbyyourcollegeexperience,youaren
Comparedwithtraditionalcomputerscience,webscienceincludestheresearch__
Comparedwithtraditionalcomputerscience,webscienceincludestheresearch__
[audioFiles]audio_eusm_j22_001(20082)[/audioFiles]A、Sciencecourses.B、Mathemat
Foraboutthreecenturieswehavebeendoingscience,tryingscienceout,usi
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoev
[originaltext]Theworld’ssmartestadolescentsinmathematicsandsciencear
Britain’sdependencyoncertainessentialserviceshasgreatlywidenedandbecom
随机试题
A—employeesB—personnelC—payrollD—white-collarE—blue-collarF—managementand
WhenIwasinthewaitingroomatthestationyesterday,Ireadamagazineinor
PartⅡReadingComprehension(SkimmingandScanning)Directions:Inthispart,y
土钉墙适用于()土质场地。A.软土 B.含水量高的土 C.淤泥 D.
大体积混凝土不宜选用( )。A.矿渣水泥 B.火山灰水泥 C.硅酸盐水泥
在0.1mol/L的CH3COOH溶液中存在如下电离平衡CH3COOH?CH3C
下列产品中,()所属的市场类型不属于完全竞争的市场结构。 Ⅰ.高科技产品
患者女性,28岁。发育正常,婚后夫妇同居,3年未孕。诊断为原发性不孕。患者想了解
A.炒焦品 B.麸炒品 C.清炒品 D.酒炒品 E.炒炭品处方名枳壳,调
对新生儿窒息进行复苏,最先施行的根本措施是( )。A.药物治疗 B.建立呼吸
最新回复
(
0
)