时间:2019-01-26 作者:英语课 分类:英语听力文摘 English Digest


英语课

Why is it that you can’t put down hydrogen gas? If you had a big balloon full of hydrogen gas, like the first gondola 1 balloons pioneered in 18th-century France, you’d find that it rises in the air quite dramatically.



You know that a piece of wood will float in water, right?


Sure.


That’s because the wood is less dense 2 than the water. When you’re in a buoyant medium, having a lesser density than your surroundings means you’ll float. Something with greater density than water, like a stone, will sink.



Air also has the quality of buoyancy. Anything less dense than the air will rise, just like a piece of wood held underwater and then let go. Hydrogen gas is only about one fourteenth as dense as air. So up it goes!


In fact, it rises with such force that it can even haul up a huge balloon, with a gondola and riders!




为什么氢气总是会飘起来?如果你有一个充满氢气的大气球,就像18世纪法国飞行先去发明的吊篮热气球,你会发现热气球在空中飘得很高。



你知道一块木头能浮于水上,是吧?因为木头密度比水的密度小。当你所在的浮力介质密度小于周围,你就会飘起来。石头一类密度大于水的密度的就会下沉。



空气也有漂浮的特质。密度小于空气的就会漂浮,就像放在水下的木头会浮起来一样。



氢气的密度仅仅是空气密度的1/14,所以氢气能漂浮。而氢气上升的力量足以托起载客的吊篮热气球。



 



n.威尼斯的平底轻舟;飞船的吊船
  • The road is too narrow to allow the passage of gondola.这条街太窄大型货车不能通过。
  • I have a gondola here.我开来了一条平底船。
a.密集的,稠密的,浓密的;密度大的
  • The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
  • The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。
学英语单词
above freezing
air buoyancy correction
alcohol-marijuana
andes holiday dances (s. america)
atopognoses
auto factory
back-passes
backspin rolls
balloonings
battersoable grommet
black right whale
bobba
bogus transaction
bounded
broadwise broken
cab tyre
card image format
ceramic-metal combination
cerberin
charge spectrum
cholesteryls
classification of disease and injury
cobra lilies
contract sales
control-rod mounting plate
culture of tropical fish
Curiapo
CV (common version)
dark brown sugar
dermatotrophia
entry on home office books
enzyme engineering
exhaust clack
external cycloidal gear
fast Fourier transforms
ferdinand magellans
Findlay, Mt.
first fillmass
fractional sound
Fritillaria maximowiczii
full implement
gemma
gigglingly
glycoaminoglycans
green-and-yellow
hafu
homestar
Hose Connectors
hypertensive rat
IASLC
internal premise
komiyama
land recovery area
lemnian earth (cimolite)
management by compartment
mast pivot bracket
micheal
microprogramming tool
mindlin-herrmann rod theiry
molecular medicine
mucomimetic
narrow fabric loom
native cranberries
nsoa (nuclear safety operatios analysis)
number of twists
oldfashioned
parameterize
pay streak
phenisonone
phoresis
pivaloyl
polytheizing
potassium selenocyanate
predicative cases
private labour and social labour
pump disk
Purbeckian stage
Regio orbitalis
regular-interval
rider carrier
Rimocortius
rolly polly
salonicas
scientific-discovery
sea jungle
shared data base
shrink packaging machine
Spittal an der Drau
stabilized loop
sucrose esters of fatty acids
surjection
Switserland
taungya system
texture discrimination
thallic fluoride
three-day-events
thunder lizards
true motion indication
two-out
undersurface filling
unmanned weather station
vicious circle