PHYSICS 



1657 



PHYSICS 



structure. The atmosphere, which envelopes 

 the globe on all sides, is another division of 

 this branch of geography. Included in this 

 division is the study of the composition of the 

 air, its pressure and elastic-it y. the 

 variations in temperature, the movements of 

 the air, the seasons, zones, storms, rainfall, snow 

 and kindred topics. The land and water en- 

 velopes of the earth are also studied in detail 

 in physical geography. This science tn-ats of 

 tin- depth and area of the various ocean di- 

 >ns. of the color, temperature and com- 

 position of ocean fl current-, tides and 

 waves, of the contour and characteristics of the 

 ocean floor, and of the formation of conti- 

 nental shelves. Seas and lakes are al-o studied 

 In taking up the land surface of the globe, one 

 would study the character, location and forma- 

 tion of continents, plains, plateaus, mountain.-, 

 rivers, valleys and islands. At all fimes. 

 'through the work of heat, atmosphere and 

 running water, ami through other agencies, the 

 appearance of the earth is undergoing many 

 change^. It i.< the province of physical gi 

 raphy to mve.-tigate and cla-.-ify \\\< 

 of change and >nuly tip Ir i- one of 

 the llHt fa.-cinaling of the >cu Il< 



Consult Lake's l'lnm\<-<tl <',< //ra/;/i,/ .- Abbott's 

 \Vnt<r <in<l I.nnil; Kinsley's Mtuldin Hair and 

 Lady Why; Mills' Ilralm of N<f 



ltel:in l -ul.j. -i'li. 'I'll-- scope of this branch 

 of geography i indicated by the ninii-n>us top- 

 \cs directly related \ it. and tin- render is re- 

 ferred to the subhead I'htiNiml <;<<>, inifihti ill tin- 

 list of related subjects following tin- article GE- 

 OGRAPHY (page 2431). 



PHYSICS, /iV/A-x. Boys and girls, if they 

 are natural, are always asking que-tion.-. nm-t 

 of which begin with Why ami How. So with- 

 out knowing it they are students of physics, 

 for, although thL* mien-ting science does not 

 answer questions of all sorts, it does tell the 



why and the how of mo-t of the things WC 8C6 

 about u.- in our daily live-. The word pkysics 

 nrn the Creek word for mi//n. and foi- 

 ' lie science was called natural philosophy. 

 It then included a number of subjects chem- 

 istry, astronomy. and others which 

 now treated as individual sciences. It 

 -till tells us about the forces of nature, about 

 and water, about light I >ound. 



aboi; ity and about how man hi- uti- 



! hi- knowledge of all thc-e to in.ik. iu- 



ion- that a boy 

 or girl cm aiMwt 



-lildy of the plllicipl. - Of pi.' 



Why is the end h..y likely to be thrown when 

 you play crack-the-whip? 



Why will ink climb up into a piece of blotting 

 paper? 



Why does oil flow faster if you take tl 

 off the t>p of the c;mV 



Why is a jerk more apt to break a string thnn 

 ;i' >t--:idy pull? 



Why is it hard to open a door if you push near 

 the. hinged side? 



What makes a ball bounce? 



' Does a piece of iron fall faster than a stick of 

 wood? 



Why do pi. < -es of pap-r Moat upward from a 

 bonfire? 



Why do tall books tip over easily? 



It" a railroad train has smooth st--l wheels ami 

 the track is smooth steel why do not the wheels 

 spin around without moving the train? 



Why is it easier to lift a stone under water 

 than above it? 



How does a fireless cooker work? A thermos 

 bottle? 



I low is it possible to make artificial ice? 



Could water in a pipe flow over a hill if the 

 top of the hill were higher than the source of the 

 water ? 



With two pieces of water pipe, one ten times 

 the diameter of the other, how could you make a 

 machine that would enable you to raise a weight 

 of one thousand pounds with . 



Why does a baseball thrown into the air travel 

 in a curve? 



Why does a door make a noise when it slams? 



Why does a paddle look bent at the point where 

 it enters the water? 



What the Science Does for Us. An African 

 explorer tells of climbing the snow-clad Ru- 

 wenxori Mountain, which is situated exactly at 

 the equator, and taking as luggage bearers a 

 number of unclad native-. When he camped 

 for the night at a point -everal thousand feet 

 above the .-ea. he gave to each man a h- 

 woolen sweater, but a few hours later he found 

 the poor fellows huddled together, half-ii 

 and still naked, for they did not know that 

 clothes would keep them warm. The story il- 

 lu-trates the fact that tin* human race is de- 



pendent Upon It- knowledge of ph\-ic:il law- 

 for its simpl'-.-t material comforts. Hut the ad- 

 vantage of physics does not stop with -imple 

 thing-. All of u- ha\e at one time or another 

 tri-il to count the wonderful inventions that 

 ha\e been ma our fathers were young. 



and every imention \\e can name was the 



iiln i of tl ion of known laws 



**, or of the discovery of new ones. 

 Thus no man could ha\< mad. a phonograph 

 without knowing \\hat sound is. nor have limit 



Ilrv-cai -y-t. in without und -r-t. Hiding the 

 mi urn of l ctnrii v. 



,,,,,t,il 



v 



; Car- 



