时间:2019-01-08 作者:英语课 分类:Scientific American(十)月


英语课

 This is Scientific American-60 Second Science. I am Christopher Intagliata. Gotta a minute?


 
Hair helps keep you warm, right? But hair can also keep you cooler than bare skin, as long as the hair is not too thick. So says a study in a journal-Plus One.
 
Reseachers studied elephants which have very thin coats of hair. It's easy for the beasts overheat, they may face temperatures up to 120 degrees Fahrenheit 1, and they don't have much skin surface area to radiate the heat relative to their big body volume. That's where the hair comes in. The reseachers wrote equations modelling the elephants hairy skin. As is expected, the thick hair traps air and keeps the body warm. But below a certain density 2, hair stops insulating, and wakes heat off the body instead, helping 3 the elephants get rid of an extra 20% of their body heat, especially on windless days. Heat sinks inside computers work in a similar way, with pin sticking up to help dissipate the interior heat. The researchers speculate that hair may actually evolve to help animals stay cool, because the first sprouded mammals over a 100 million years ago in a hot climate. Hair raising time indeed.

n./adj.华氏温度;华氏温度计(的)
  • He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
  • The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。
n.密集,密度,浓度
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
n.食物的一份&adj.帮助人的,辅助的
  • The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
  • By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。
学英语单词
Acalypha caturus
acrolect
acropsylla (acropsylla) girshami
air tourist
alidochlore
analysis and production
automatic feed-rate control system
barred type pump
be in someone's black books
bottom wire
broadheaths
brooder
chromokinesin
cometographer
computer orphan
connectances
Consturcts
crackleberry
creeping soft grasses
cyders
dakoit
data virtualization
deftness
diffusion molding
dipole moment
drug-uses
electronic cinema
emotivities
ensilage cutter-blower
erythema pudicitiae
Essequibo
excepted
F. h.
fiscard
flame failure control
galactosidae
Gambia kino
giga-coulombs
Govǐ-Sümber Aymag
gum inhibiting index
haustra of colon
heckmair
herpes zoster keratitis
honeycomb ringworm
hour mechanism support banking ring
iliosacralis
infratemporal surface
interrogator-responder system
jet ballast tank
juvarra
laccolites
logarithmic viscosity number
mark-up percentage
Mielno
milk the profits
mithramycin
moco cotton
morphogenesis
Neospongophyllum
netpliance
nonuniformly distributive coupler
nozzle outlet gas angle
oxygen breathing apparatus
oxygenizable
ozonoscop
pachyonychia congenita
petrol-depth gauge
pitch diameter of drum
preformatting
Prikaspiyskiy
production supply marketing relation
pyrogallol
rated field current
re-homed
reach the standard
reactants
reversed phase partition
riceballs
roll(ing) mill
rumbling
samedan (samaden)
sanitation cutting
seamless
shellwork
siff
single program/multiple data
slow frequency hopping
Spc3p
start of heading
sugan
Sze Yap
taleteller
target power
TCAM (telecommunication access method)
three problems in greek geometry
timed sequence
total loss cover
tripping coil
tripudiary
unbinding
undelectable
velocitron