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


英语课

   Night Vision And Humans: Why Can’t We See Color?


 
  When we are in a fairly dark room, or outside at night away from lights, we can still see, but we can’t see the colors of things very well. Why is that?
 
  There are two kinds of light-sensitive organs located in the backs of our eyes: rod-shaped and cone-shaped. Both rods and cones 1 are sensitive to light. The difference between them is that the rods allow us to see in very dim light but don’t permit detection of color, while the cones let us see color but they don’t work in dim light.
 
  When it gets dark the cones lose their ability to respond to light. The rods continue to respond to available light, but since they cannot see color, so to speak, everything appears to be various shades of black and white and gray.
 
  A curious thing is that in dim light you can see more clearly out of the side of your eye, because the light-sensitive rods are more highly concentrated off to the side in the back of your eye.
 
  So, next time you’re out on a clear night, notice how little color you can see, and how you can see objects like dim stars better out of the corner of your eye than from the center.

n.(人眼)圆锥细胞;圆锥体( cone的名词复数 );球果;圆锥形东西;(盛冰淇淋的)锥形蛋卷筒
  • In the pines squirrels commonly chew off and drop entire cones. 松树上的松鼠通常咬掉和弄落整个球果。 来自辞典例句
  • Many children would rather eat ice cream from cones than from dishes. 许多小孩喜欢吃蛋卷冰淇淋胜过盘装冰淇淋。 来自辞典例句
学英语单词
abortiva variola
allegan
amblyeleotris periophthalma
animal husbandry
application for drawback
autoselecting
basic atomic group
be a scorn to
bear-trap
beechy
bepraising
brans-dicke
break-even point
British Radio Communication
broglies
Brumado
Buendia, Embalse de
can-carrier
catch lever
cinoas
clathtate
clowning around
copper stripping electrolysis
Crotalus viridis
decking level
deconjugations
dennisonite (davisonite)
Derrick City
differentiabilities
diplococcus of Morax-Axenfeld
double-current method
El Bejuco
end-of-field marker
equity-warrants
finds oneself
flash of wit
force due of viscosity
gate current degradation
give tongue
glooming
half yearly account
hexaferrite
huskershredder
inertinites
inomyxoma fibromyxoma
Isonin
kerak
kolstad
lay of rope
Lena Trough
limit position of a link
lining method
mafes
malonyl thiourea
megalithic age
methidium
mixed sleep apnea
modem connection
mushroom cloud
notacaphylla chinensiae
occipitoiliac
older sisters
one bath two stage process
overpraises
pay honor to
pentamethazene
Phospatidylcholine
play close to the vest
premonitory pains
primary productivity
proxy attribute
psychic deafness
quarter wave length
queue type
reheating cycle
rim blight
Sabbathesque
sagueiro
sand shell moulding
sand stargazer
saracenis
sillenite
simultaneous prosperity
softball
spread oneself
Stellaria irrigua
stellasteropsis colubrinus
strategic communication
student experience
succinanilide
sunnyside up
take-up bearing
terminal wire
turbo fan
twin engined
unpathetic
vibration ramming
virtual disk system
wack
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zero power level
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