A Guide To The Scientific Knowledge Of Things Familiar - novelonlinefull.com
You’re read light novel A Guide To The Scientific Knowledge Of Things Familiar Part 42 online at NovelOnlineFull.com. Please use the follow button to get notification about the latest chapter next time when you visit NovelOnlineFull.com. Use F11 button to read novel in full-screen(PC only). Drop by anytime you want to read free – fast – latest novel. It’s great if you could leave a comment, share your opinion about the new chapters, new novel with others on the internet. We’ll do our best to bring you the finest, latest novel everyday. Enjoy
Q. _Why are DARK COLOURS (for external wear) so much WARMER than LIGHT ONES?_
A. Because _dark colours absorb heat from the sun_ more abundantly than _light_ ones.
Q. _How can you prove that DARK colours are WARMER than LIGHT ones?_
A. If a piece of _black_ cloth and a piece of _white_ were laid upon snow, in a few hours the _black cloth will have melted the snow beneath_; whereas the _white_ cloth will have produced little or _no effect upon it at all_.
N. B. The darker any colour is, the warmer it is, because it is a better absorbent of heat. The order may be thus arranged:--1. Black (warmest of all).--2. Violet.--3. Indigo.--4. Blue.--5. Green.--6. Red.--8. Yellow: and 9. White (coldest of all).
Q. _Why are BLACK KID GLOVES so HOT in summer time?_
A. 1st--Because the _black absorbs the solar heat_: and
2ndly--The _kid_ will not allow the heat of the hand _to escape through the glove_.
Q. _Why are LISLE THREAD GLOVES so COOL in summer time?_
A. 1st--Because thread _absorbs the perspiration of the hands_: and
2ndly--It _conducts away the heat_ of our hot hands.
Q. _Are Lisle thread gloves ABSORBENTS of heat?_
A. As Lisle thread gloves are generally of a _grey or lilac colour_, they do _not absorb solar heat_.
Q. _Why is a PLATE-WARMER made of UN-PAINTED BRIGHT TIN?_
A. Bright tin reflects (or _throws back_) _the heat_, which issues from the fire in rays; and (by reflecting the heat upon the meat) a.s.sists greatly in roasting it.
Q. _Why would not the tin REFLECTOR do as well if it were PAINTED?_
A. If the tin reflector were _painted_, it would be utterly spoiled, because it would then _absorb_ heat, and _not reflect it at all_. A plate-warmer should be kept _very clean, bright, and free from all scratches_.
Q. _Why should a REFLECTOR be kept so very CLEAN and free from SCRATCHES?_
A. If a reflector be _spotted, dull, or scratched_, it will _absorb_ heat, instead of _reflecting_ it; and, therefore, would be of no use whatsoever as a _reflector_.
Q. _Why does h.o.a.r-FROST remain on TOMBSTONES, long after it has melted from the GRa.s.s and GRAVEL-WALKS of a church-yard?_
A. Tomb-stones being _white_, will _not absorb heat_, like the darker gra.s.s and gravel; and, therefore, _the white tombstones_ (being so much colder) _retain the h.o.a.r-frost_ after it has melted from other things.
Q. _If black absorbs heat, why have those who live in HOT climates BLACK SKINS, and not WHITE skins (which would not absorb heat at all)?_
A. Though the black skin of the negro _absorbs heat_ more plentifully than the _white skin of a European_, yet the _blackness_ prevents the sun from _blistering_ or _scorching it_.
Q. _How is it known that the BLACK colour prevents the sun from either BLISTERING or SCORCHING the skin?_
A. If you put a _white glove_ on _one hand_, and a _black glove_ on _the other_ (when the sun is burning hot), the hand with the _white_ glove will be _scorched_, but _not the other_.
Q. _Which hand will FEEL the HOTTER?_
A. The hand with the _black glove_ will _feel_ the _hotter_, but it will not be _scorched_ by the sun; whereas the hand with the _white glove_ (though much _cooler_) will be _severely scorched_.
Q. _Why does the BLACK skin of a NEGRO NEVER SCORCH or BLISTER with the hot sun?_
A. Because the _black colour absorbs_ the heat,--conveys it _below the surface_ of the skin, and converts it to _sensible heat_ and _perspiration._
Q. _Why does the WHITE EUROPEAN SKIN BLISTER and SCORCH when exposed to the hot sun?_
A. Because the _white will not absorb_ the heat; and, therefore, the hot sun _rests on the surface of the skin_, and scorches it.
Q. _Why has a NEGRO BLACK EYES?_
A. The black colour of a negro's eyes defends them from the strong light of the tropical sun. If a negro's eyes were not _black_, the sun would _scorch them_, and every negro would be blind.
Q. _Why is WATER KEPT COOLER (in summer time) in a BRIGHT TIN POT, than in an EARTHEN one?_
A. Because bright metal will _not absorb_ the heat of the summer sun, like an _earthen_ vessel.
Q. _Why is BOILING water KEPT HOT in a BRIGHT TIN VESSEL longer, than in an earthen one?_
A. Because bright tin will not suffer the heat of the boiling water _to escape in rays_, as an earthen vessel does.
CHAPTER XV.
3.--REFLECTION OF HEAT.
