时间:2018-12-31 作者:英语课 分类:英语听力文摘 English Digest


英语课

   In the 17th century, the French scientist Pierre Gassendi knew that light traveled faster than sound. When a gun fired far away, he could see the flash of gunshot long before he heard the report.


 
  Gassendi tried to measure the speed of sound by clocking the time that elapsed between the flash and the gunshot. Knowing the exact distance the gun was from him, he calculated that sound traveled through air at over 1,000 miles per hour. This figure is too high, though. Can you guess why?
 
  The problem was that Gassendi relied on his own reaction time, making his measurement higher than it should have been.

  In 1864, another French scientist, Henri Regnault, devised a way to measure the speed of sound automatically, again by using a gun, but without relying on human reaction time. Regnault covered a rotating cylinder 1 with paper, and positioned a pen to draw a line as it turned. Next, he wired the pen to two electrical circuits, placing one in front of the gun some distance away, and the second near the cylinder, threaded through a diaphragm sensitive to sound.
 
  When the gun fired, the first circuit broke, making the pen jump to a new position on the rotating cylinder. When the sound reached the diaphragm by the cylinder, the pen jumped back to its original position. Because Regnault knew how far the gun was from the cylinder and how fast the cylinder turned, he calculated that sound travels through air at 750 miles per hour, quite close to the speed physicists 2 accept today.

n.圆筒,柱(面),汽缸
  • What's the volume of this cylinder?这个圆筒的体积有多少?
  • The cylinder is getting too much gas and not enough air.汽缸里汽油太多而空气不足。
物理学家( physicist的名词复数 )
  • For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说,这是受挫折的一年。 来自英汉非文学 - 科技
  • Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。
学英语单词
accounting recapitalization
additional markup
al hammam
analog network
angle acquisition
anticipation network
antipoaching
antiviolence
apfelstrudel
aristostigment
atom economy
autoaggressive disease
axiolinguoclusal
bekaa valley
benzothiadiozine
CaM-KK
ccaproyl
choking
climate during brief spring and summer
co-part
cockshut
complete chaos
contractual dividend
CynanchoI
dandruff control shampoo
dead expense
dierotophos
direct profit
ditsiest
drawing advice
electrostriction effect
emplectum
engkoo
equal-angle projection
FIFO algorithm
fish loin
flame-core
formose
forward stroke of the piston
fuentes de onoro
haloalkyl
handwriting instruction
hierodeacon
impurpure
indirect-action controller
intramontane basin
invulgared
Ionioi Nisoi
jeljaszewicz
k bentonite
Kirzhachskiy Rayon
legal capacity of juristic person
Leo Szilard
limit on banknote issue
long rolling swell
loots
major minor loop organization
make fun of him
man machine language
materialman
mechanical amplitude
mojari
Morrison hour
multiple bus control processor
navigable semi-circle
Neottia listeroides
network news
non-packable
nrif
nutritional megaloblastic anemia of infancy
opacified
paradoxite
partiment
Pentire
photo ionization process
Platinol
prolate epicycloid
propyl nitrolic acid
rainfly
rapid acting developing agent
rise heading
saidpurs
sample surface
seawater physics
service center accounting
soap dispensers
spasm of tongue
standby period
stenophotic organisms
symbolic queue
tick-bornes
UCITA
ultrafractionation
unfair sales acts
upshifters
vegasite (plumbojarosite)
vessel flange
wake simulation
wall mustard
wet rubbing
wiffleball
ya dig