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
acculturational
Ahok
air servicer
air tube connector
allylisulfocarbamide
Alyssum lenense
annealing kiln
anti-detonant
arggh
bainitic
bank eligible bonds
birdsat
body persecution
butter knife
chin implant
cotton ball cloud
crankcase mayonnaise
crime of affray
crow pram
current collecting equipment with liquid metal
dilettanteish
Distoma hepaticum
DJC
drawing-in machine
elingued
epidihydrocholesterin
even zonal harmonics
exclusive-NOR gate
Fenmetrazin
fetichises
flowind
galula
gavots
glyco-nucleoprotein
group technology code
head-emptier
heat sensimeter
hyperbolic variational inequation
hypersensitive angiitis
impact matrix
Inner Manchuria
inscription on a tablet
interactive placement
Irurita
keesee
Kraynovka
lateral distal mandibular
layettes
layzer
ligmentum popliteum arcuatum
limits of audition
loflucarban
M.Ap.L.
metzincins
minimum-size
Nam Ha
nominal pressure rating
one-block
package management system
people's
photo typography
platinum resistance thermometry
Platt.
plot a distance
plumb perpendicular
predations
premature eruption of tooth
prison gangs
psychosociology
puts together
rectalox glaberi
respiratory environment
restored nonevent
Roulans
Samaritan Pentateuch
shaping amplifier
shipments sent
sill splicing
simple analytic function
somniferum
sound source room
spider-web antenna
spot radiation source
sunshine pill
Swainsona salsula
Syncalathium disciforme
tapman
tea-dancer
telepathising
tensor geometry
thromboresistant
to bake
toll communication network
tracer compound
travelblogs
ultrapure material
underinflated
use exertions
vaginal discharges
Veterans Affairs
vittore carpaccio
Vygozero, Ozero