A Guide To The Scientific Knowledge Of Things Familiar - LightNovelsOnl.com
You're reading novel online at LightNovelsOnl.com. Please use the follow button to get notifications about your favorite novels and its latest chapters so you can come back anytime and won't miss anything.
A. Yes; and was, therefore, a plain _demonstration of the power of G.o.d_, who could change the very _nature of things_ at his will.
Q. _Why do our CLOTHES FEEL DAMP, after walking in a fine evening in SPRING or AUTUMN?_
A. Because the vapour (_condensed by the cold earth_) lights upon them, like dew.
Q. _Why are WINDOWS often covered with thick MIST, and the frames wet with standing WATER?_
A. The temperature of the _external air_ always _falls at sun-set_, and _chills the window-gla.s.s_, with which it comes in contact.
Q. _How does this account for the MIST and WATER on a WINDOW?_
A. As the warm vapour of the room _touches the cold gla.s.s_, it is _chilled_ and _condensed into mist_; and the mist (collecting into drops) _rolls down the window-frame_ in little streams of water.
Q. _Does the GLa.s.s of a window COOL down more RAPIDLY than the AIR of the room itself?_
A. Yes; because the air is _kept warm by fires_, and the _animal heat_ of the people in the room; in consequence of which, the _air of a room suffers very little diminution of heat_ from the setting of the sun.
Q. _Whence arises the VAPOUR of a ROOM?_
A. 1st--The very _air_ of the room _contains vapour_:
2ndly--The _breath_ and _insensible perspiration_ of the inmates _increase_ this vapour: and
3rdly--_Hot dinners_, the _steam of tea_, &c. contribute to _increase it still more_.
Q. _What is meant by "the INSENSIBLE PERSPIRATION?"_
A. From every part of the human body an _insensible and invisible perspiration issues_ all night and day; not only in the hot weather of _summer_, but also in the coldest day of _winter_.
Q. _If the perspiration be both INSENSIBLE and INVISIBLE, how is it KNOWN that there IS any such perspiration?_
A. If you put your naked arm _into a clean dry gla.s.s cylinder_, the _perspiration_ of your arm will soon _condense_ on the gla.s.s, like mist.
Q. _Why are CARRIAGE WINDOWS very SOON covered with thick MIST?_
A. The warm vapour of the carriage _is condensed the moment it touches the cold gla.s.s_, and covers it over with a thick mist.
Q. _Why is the gla.s.s window COLD enough to condense the vapour of the carriage?_
A. Because the _inside_ of the carriage is much _warmer_ than the _outside_, and the gla.s.s window is made cold by contact with the _external air_.
Q. _Where does the WARM vapour of the carriage come from?_
A. The warm _breath_ and _insensible perspiration_ of the persons riding in the carriage, load the air of it with warm vapour.
Q. _What is the cause of the pretty FROST-WORK seen on bed-room WINDOWS in winter-time?_
A. The _breath_ and _insensible perspiration_ of the sleeper (coming in contact with the ice-cold window) is _frozen_ by the cold gla.s.s, and forms those beautiful appearances seen in our bed-rooms in a winter morning.
Q. _Why is the GLa.s.s of a window colder than the WALLS of a room?_
A. Gla.s.s is a very _excellent radiator_; and, therefore, most _rapidly parts with its heat_.
Q. _Why is a TUMBLER of cold WATER made quite DULL with mist, when brought into a room FULL of PEOPLE?_
A. Because the _hot vapour of the room_ (coming in contact with the cold tumbler) _is condensed upon it_; and changes its invisible and gaseous form for that of a _thick mist_.
Q. _Why is a GLa.s.s made quite DULL, by laying a HOT HAND upon it?_
A. The _insensible perspiration_ of the hot hand is _condensed_ upon the cold gla.s.s, and thus made perceptible.
Q. _Why are WINE-GLa.s.sES made quite DULL when they are brought into a room FULL of COMPANY?_
A. The _hot vapour of the room_ (coming in contact with the cold wine-gla.s.ses) _is condensed_ upon them, and covers them with vapour like dew.
Q. _Why does this misty appearance GO OFF after a little time?_
A. Because the gla.s.s becomes of the _same temperature_ as the _air of the room_, and will no longer _chill the vapour_ which touches it, and _condense it into mist_.
Q. _Why is a WINE-GLa.s.s (brought out of a CELLAR into the AIR) covered with a thick MIST in summer-time?_
A. The vapour of the hot air is _condensed_ by the cold gla.s.s, and covers it as a thick mist.
Q. _Why does BREATHING on a GLa.s.s make it quite DULL?_
A. Because the hot breath is _condensed_ by the cold gla.s.s; and, therefore, covers it with a thick mist.
Q. _Why do WALLS stand thick with WET in a sudden THAW?_
A. The walls (being thick) cannot _change their temperature so fast_ as the thin air can; and, therefore, they _retain their cold_ after the thaw has set in.
