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


英语课

   Even as adults we still enjoy blowing bubbles, don’t we? If you’ve ever wondered why blowing on a thin film of soapy water creates bubbles, this is your lucky day.


 
  All liquids have a property called surface tension. Take water, for example. Water molecules 1 are strongly attracted to each other.
 
  Therefore the molecules on the surface of the water are not attracted towards the air, but rather towards the rest of the water. This attraction is what creates surface tension, forming a sort of skin on the water’s surface.

  Surface tension is also what accounts for soap bubbles. Dipping a wand into regular water won’t work because the water’s surface tension is so strong that the molecules would rather bunch together in a puddle 2 than be stretched across the opening of the wand.
 
  The addition of soap helps because these molecules have two distinct ends, one that is attracted to water, and one that is not.
 
  When a wand is dipped into soapy water, soap molecules cover the surface of the film, with their water-loving ends facing the water. Since the water molecules are now attracted not only to each other but also to one end of the soap molecules, the water is held in place as it stretches across the wand, forming a soapy film.
 
  Blowing into the film is similar to blowing into a balloon: the rush of air makes the film stretch and expand. Surface tension makes the soap water molecules still attached to the wand automatically come together, closing the developing bubble’s open end.
 
  Once this happens, sealing the air inside its skin, the completed bubble releases and floats away.

分子( molecule的名词复数 )
  • The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
  • Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
n.(雨)水坑,泥潭
  • The boy hopped the mud puddle and ran down the walk.这个男孩跳过泥坑,沿着人行道跑了。
  • She tripped over and landed in a puddle.她绊了一下,跌在水坑里。
学英语单词
able rating
absolute measurement method
amphiprion perideraion
application for admission
approximate market
aquifar test
attachment site
back-basket store
backswimming
bin system
bituminic
Boolean operators
bother oneself with
Brummagems
Caledon River
chronic heat exhaustion
coddler
common base current gain
concurrent negligences
conduit connection
cyclic ignorable coordinate
dark-sided
deacetylranaconitine
deratization certificate
double resonance
Dänischenhagen
effused-reflexed
equal aquals
equiblast cupola
extra-quranic
fixed points method of calibration
free storage period
frost fog
gas show
green colour
greenlit
Gris-PEG
hamlock
heart-leaved aster
horizontal resolution bars
hot-mix plant
humitas
hypothec bands
income tax on joint venture
indirect analog
individualized manpower training
inquisitivenesses
integrated software line
Interdev
ipropethidine
levy en masse
logistic regression
machine-element
MacS.
make a poor appearance
medical-devices
milli-webers
Moorewood
moorstone
nanobe
neocolonialisms
neutron fluxes
newricall
numerical subroutine library
Orchis kunihikoana
origin of the atmosphere
pale-golds
para-pentyloxy-phenol
payment in arrears
peroxybenzoic acid
pharyngeal opening of eustachian tube
poisonou
propargylchloride
rotary cup atomizing oil burner
rouke
round-necked
sack lunches
sailwing wind generator
sand-castles
self-incompatibillity
sideyways
simple chancre
slow sticking
spanghewed
structural var (svar)
swell-shrink characteristics
tannin idioblast
taran
tedd
tensile stressed skin
third-generation phototypesetter
three-part harmony
transitivity of equivalence relation
ultrahigh voltage transformer oil
uniformly placed
use bit
vicka
vidas
weed control chemicals
wishful thinking
Yerkish