. The principles of physics. expands and comes out through theliquid in bubbles. After a few minutes withdraw the heat, keeping the 268 MOLECITLAR DYNAMICS. end of the tube in the liquid; as the air left in the flask cools, its pressuredecreases, and the water is forced by atmospheric pressure up the tubeinto the flask, and partially fills it. Experiment 5. — Partly fill a foot-ball with coldair, close the orifice, and place it near a fire. Theair will expand and distend the ball. 228. Expansion - ooefficients. — The ex-pansion which attends a rise of tempera-ture depends not only upon the siz
. The principles of physics. expands and comes out through theliquid in bubbles. After a few minutes withdraw the heat, keeping the 268 MOLECITLAR DYNAMICS. end of the tube in the liquid; as the air left in the flask cools, its pressuredecreases, and the water is forced by atmospheric pressure up the tubeinto the flask, and partially fills it. Experiment 5. — Partly fill a foot-ball with coldair, close the orifice, and place it near a fire. Theair will expand and distend the ball. 228. Expansion - ooefficients. — The ex-pansion which attends a rise of tempera-ture depends not only upon the size of thebody, and upon the number of temperaturedegrees through which it is heated, butupon a quantity peculiar to the substanceitself called its expansion-coefficient. Thisterm is applied to the increase of unit-lengthper degree ri§e of temperature. Suppose that a rod of length I at 0° C. beheated through t degrees, so that its lengthbecomes l-i; then, representing the linear expansion-coefiicientby c, we have I, —I. Fig. 208. It whence Zj = ^ (1 + ct). The expression 1 + ct, called the expansion-factor, is evi-dently the ratio of the final to the original length. - HenceZj ^ Z (1 -|- ci) ; that is, multiplying the length of a solid at0° C. by the expansion factor gives its length at t degreesabove zero. Conversely, dividing its length at t° by theexpansion factor gives its length at 0°. Taele of Mean Coefficients of Linear Expansion between 0°AND 100° C. Glass Platinum . Steel . Wrought iron . Cast iron Gold Copper Brass Silver Tin . . Lead Zinc FORCE IN EXPANSION AND CONTRACTION. 269 In the expansion of fluids we have to do only with increaseof volume, called volume or cubical expansion. A volume-expansion-coefficient is the increase of unit volume per degreerise of temperature. This is approximately 3 c, or three timesthe linear expansion-coeificient, a
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1895
