时间:2018-12-27 作者:英语课 分类:英语时差8,16


英语课
Heavy air on this Moment of Science.
 
Here's an oxiny question: does air weigh anything?
 
At first it might seem preplexing, on the one hand, air just seems floating, I mean, to say something is as light as air is to say its weighlessness, is isn't? 
 
But then, a strong wind can pull floations down and set things fly. So air isn't exactly nothing. Air doesn't affect to have a weight and here's a simple way you can prove it.
 
You'll need two identical balloons, a string and a doul. Test the uninfeded balloons to either end of the doul, test the string to the center of the doul and then hanging it from something. If the baloons are very nearly identical, the doul should hang evenly without tipping to either side. You now have a basic scale. Next, inflate 1 one of the balloons by blowing into it, what happens? You bet, the side with inflated 2 balloon hangs lower than the other side. You have demonstrated that air has a weight.
 
The simply demonstration 3 sometimes confuses people. Why does a balloon filled with air fall? When it's only surrounded by air, why doesn't it just remain where it is? The answer lies in density 4. Any fluit anything that has a greater of density than its surroundings will sink. When you blow the baloon, you are increasing its overall density by forcing air inside it. That's because the air inside the baloon is under greater of pressure than the air outside. It's being squeezing entirely 5 by the sides of the balloon. Greater pressure it's greater of density so the heavy air inside the balloon will fall.

1 inflate
vt.使膨胀,使骄傲,抬高(物价)
  • The buyers bid against each other and often inflate the prices they pay.买主们竞相投标,往往人为地提高价钱。
  • Stuart jumped into the sea and inflated the liferaft.斯图尔特跳到海里给救生艇充气。
2 inflated
adj.(价格)飞涨的;(通货)膨胀的;言过其实的;充了气的v.使充气(于轮胎、气球等)( inflate的过去式和过去分词 );(使)膨胀;(使)通货膨胀;物价上涨
  • He has an inflated sense of his own importance. 他自视过高。
  • They all seem to take an inflated view of their collective identity. 他们对自己的集体身份似乎都持有一种夸大的看法。 来自《简明英汉词典》
3 demonstration
n.表明,示范,论证,示威
  • His new book is a demonstration of his patriotism.他写的新书是他的爱国精神的证明。
  • He gave a demonstration of the new technique then and there.他当场表演了这种新的操作方法。
4 density
n.密集,密度,浓度
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
5 entirely
ad.全部地,完整地;完全地,彻底地
  • The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
  • His life was entirely given up to the educational work. 他的一生统统献给了教育工作。
学英语单词
air inter cooler
Aitken, Robert Grant
aminoanisole
antiadhesive
apperceptive visual agnosia
asomatic acardius
badgastein
biaxial spherical harmonics
bills receivable discounted
bishop's throne
bunch into
bustle off
callocities
canarii fructus
Caryodaphnopsis latifolia
caustic neutralizer column
chaetodon burgessi
chinese dancers association (cda)
conarium
convivial
damaged by sea water
definitions
demise chartered owner
dentalising
duplex querela
economic handbook
erotisme
ethadione
euonymus nanoides sieb.
exposed conduit
fan tzu y?eh
feed dog screw
first convoluted tubule
fractional magma
free of general average
gallant soldier
glider bomb
goondah
graph entity
haemapoietic
hear sb. out
hierarchical Boolean function
high pressure leak detector
hot-work die steel
in account with
index sensing
individualized learning
industrialscale
inter-station
judicial psychology
Kakadu National Park
kournikova
Matamey
mesothermoplankton
Miacidae
moonboots
neoplastic cells
network social psychology
Network Solutions
newborn mouse
non-will
Nærum
ocv
outstanding on loans
Oxytropis biflora
P12
pair of element
parting agent
patency
pen and ink account forms
peplau
pin clovers
pinchbar
Pitres's area
poisoning yield
premium system
PUVLA
R.R.
rate of oxidation
reverse circulation drill
rounding error
saintlyness
sea-parrots
setting dial
silenite
soot blacks
supernatant liquid
survey on damage to cargo
testerically
tetrapetalose
tree-length
tumor of anterior mediastinum
vyfe
white kidney bean
white-coateds
Who Killed Cock Robin?
within door
Words are but wind,but seeing's believing.
worralls
yellowmen
Zurich agreements
zygophytic