时间:2019-03-09 作者:英语课 分类:英语听力文摘 English Digest


英语课

  What Is Fire?

火是物质燃烧过程中散发出光和热的现象,是能量释放的一种方式。火焰分为焰心、中焰和外焰,温度由内向外依次增高。燃烧过程必须有可燃物、燃点温度、氧化剂三项并存,缺一不可。火失控时,常常称作失火或火灾,危害甚大。


  The ancient Greeks believed that fire--along with earth, water, and air--was one of the four essential elements that made up the world.

It’s one of our most important tools, and holds a prominent place in many ancient philosophies and religions.  The ancient Greeks believed that fire–along with earth, water, and air–was one of the four essential elements that made up the world.  We now know that the world’s a lot more complicated, with over a hundred elements of matter which can be combined in a tremendous variety of ways.  This might leave you wondering where fire fits in.  What exactly is fire?

Watching a flame dance through the air, you might conclude that fire’s a gas, like oxygen or carbon dioxide.  It’s not.  Fire can burn fuel that’s a gas, or a liquid, or even a solid–as in the case of glowing charcoal 1.  But the fire itself isn’t any of these things.  In fact, fire isn’t any thing at all.  It’s not its own type of matter; it’s something that matter can do.  Fire is a chemical reaction.

A fire needs oxygen and some kind of fuel.  This fuel–whether it’s candle wax, wood, or gasoline–usually contains big molecules 2 that have carbon atoms inside them.  You can think of these molecules as little containers of energy.  When they’re allowed to combine with oxygen, this energy is released as heat and light.

Fire is a rapid chemical reaction known as oxidation.  Inside a fire, oxygen molecules break bigger molecules apart into carbon dioxide and water vapor 3.  All the heat and light of a fire comes from big, carbon-based molecules combining with oxygen. So what is fire?  It’s not the fuel or the oxygen or the heat or the light.  Fire is what happens between all these things.  It’s a chemical reaction.



n.炭,木炭,生物炭
  • We need to get some more charcoal for the barbecue.我们烧烤需要更多的碳。
  • Charcoal is used to filter water.木炭是用来过滤水的。
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.蒸汽,雾气
  • The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
  • This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。
学英语单词
A.E.S.
adiabatic damping
agvs (automated guided vehicle system)
alalunga
alfalfa mosaic
anticultists
aracari
aristoxenuss
Austrophobes
axis angle
bachas
bansela
barlby
Bourdeilles
Boxer Rising
brakemakers
busting
cake shampoo
Calamus rotang
calling for
centaurium calycosums
cleavable
combustible case
computer civilization
construction guide
crack filler
cutting movement
cycloprate
DEPLOC
destructive oxidation
diarthrodactylous
direct-current excited reactor
discontinuous crystallizer
Ecclestone
edging device
eleanors of aquitaine
electronic detector
end matched specimen
fetishizer
finger-prints
fleetwide
Flyte
foot-rest
forewalk
fryar
goathair
hard space
hydrodynamic aided rotary shaft lip seal
i am curious orange
in-flood
International Council for the Exploration of the Sea
Iosiderite
KUW
Ligusticum acutilobum
logic fallacies
media life
melanodon
meridional cell
nonsprouting
nuclear runaway
nucleus dentatus
oestringen
ople tree
output transfer function
parallel flow heating furnace
pebble-dashed
pentamethine
phasetrajectory
Pivoteau
Price County
rabones
radiation health physics
railway wear tolerance
ray crossing
red onions
refractometrically
Riemann-Christoffel tensor
safety protective lighting
SATA cables
sheep-stealer
shift position
Ship Re-mortgage
shoot a glance at sb
Shuakhevi
straight-through flow
straw in the wind
subs' bench
sulfoxidation
tarsoconjuntiva graft
tavernas
tetrarchic
three-section cut
tin-cans
tomographic scanner X
top-side
trabeculae cranii
trade mode
university-levels
up one level
ventral celiotomy
yummily
Zimb.