Silver Burdett/

Science: Understanding Your Environment/

Characteristics of Air p. 39/

1975/

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/

S4N4/

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/-/You know*D1 [DOthat all matter has*D1 weight and takes*D1 up space. ]/-/Rocks, water, animals-- everything=A--01 [JMyou can see*D0 ]is*N1 matter. /c/But what*E (about air? )/-/You cannot see*D1 air. /-/Is*N1 air matter? /-/You don't have to see*D1 air to know=IAV071 [DOthat it is*-1P (around you. )]/-/Just step*- outdoors and feel*D1 the wind. /-/Wind is*N1 moving=P--01 air. /-/Strong wind can overturn*D1 cars and knock*D1 down buildings. /-/Air can do*D1 these things [ARbecause it has*D1 weight and takes*D1 up space. ]/c/So, air is*N1 matter. /-/The earth is surrounded*P (by a layer )(of air. )/-/This layer (of air )goes*- (above the earth )(for many miles. )/-/All this air has*D1 great weight. /-/This weight acts*- (as a force )(on everything )(on the earth. )/-/This force is called*P1 air pressure. /-/Imagine*D1 a tall column (of air, )an inch=U--02 long and an inch=U--02 wide. /-/Suppose*D1 [DOthis column went*- (from the ground )(to the top )(of the atmosphere. )]/-/This column would be*A1 (over 2,000 )miles=U--03 tall. /-/[ALIf you could lift*D1 this column, ]what do you think*D1 [DOit would weigh?*N1 ]/F/One pound?*E /F/Five pounds?*E /F/Ten pounds?*E /-/None (of these weights )are*A1 enough. /-/The column (of air )would weigh*N1 almost fifteen pounds. /-/[ALIf you take*D1 a long stick and cut*D1 it (in two, )]neither piece will weigh*- as much (as the whole stick. )/c/But the two halves would weigh*N1 about the same.=U--03 /-/Imagine*D1 [DOthat you cut*D1 a 2,000-mile column (of air )(in half. )]/-/Each half would be*A1 1,000 miles long. /c/But (unlike the stick, )the half closer (to the earth )would weigh*N1 much more (than the top half. )!!!!!!!!