Silver Burdett/

Science: Understanding Your Environment/

The Gases in the Air p. 29/

1975/

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S4N3/

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/-/You may have heard*D1I people say=IDO081 [DOthat air is*-1P all (around you. )]/c/But how do you know?*D0 /-/You cannot taste*D1 it or smell*D1 it. /-/You cannot see*D1 it. /-/However, [ALwhen wind blows,*- ]you can feel*D1 the moving=P--01 air. /-/Air fills*D1 the spaces (on the earth )[JRwhere there are*N2 no solids or liquids. ]/-/[ALWhen you drink*D1 a glass (of milk or water, )]you may say*D1 [DOthat the glass is*A1 empty. ]/c/But it really is*A0 not. /-/[ALAs you drink*D1 the milk, ]air fills*D1 the space (inside the glass. )/-/The glass*A1 is full (of air )[ARwhen the milk is gone.*P ]/-/Air is made*P (of different gases. )/-/The gases are mixed*P together (in the same way )[JRyou might mix*D1 several solids. ]/-/Some air is found*P (in rocks. )/-/Some is found*P (in liquids. )/-/(In water, )air is dissolved.*P /-/This means*N1 [PNthat it is spread*P (among the water molecules. )]/-/[ALWhen water is warmed,*P ]some (of the air )escapes.*- /-/This is*N1 [PNwhat is happening*- (in the picture. )]/-/The warmth (of the boy's hand )is helping*D1I the air escape.=IDO030 /-/The escaping=P--01 air is*-1P (in bubbles. )/-/Oxygen and nitrogen are*N1 the two gases [JRthat make up*N1 most (of the air. )]/-/You have surely heard of*D1 oxygen. /-/Oxygen could be called*P1 the "gas (of life." )/-/(Without oxygen )there would be*N2 little or no life (on earth. )/-/Almost all living=P--01 things need*D1 oxygen. /-/The only living=P--01 things [JMthat do*D0 not ]are*N1 tiny organisms [JRyou see*D0 (with a microscope. )]/-/Oxygen is*A1 important [ARbecause it combines*- (with other substances )(on the earth. )]/-/That happens*- [ARwhen something burns.*- ]!!!!!!!!