. The principles of physics. theirswing when they have recovered their original position, but,like a pendulum, swing beyond the position of rest, thusproducing a rarefaction at B, where immediately before therewas a condensation. Thus a forward movement of the rare-faction is made, and thus a pulse or wave is transmitted withuniform velocity through a spiral spring or any elasticmedium. A wave cannot be transmitted through an inelastic softiron spiral. Elasticity is essential in a Tuedium, that it inaytransmit waves com/posed of condensations and rarefactions;and the greater the elasticity, th
. The principles of physics. theirswing when they have recovered their original position, but,like a pendulum, swing beyond the position of rest, thusproducing a rarefaction at B, where immediately before therewas a condensation. Thus a forward movement of the rare-faction is made, and thus a pulse or wave is transmitted withuniform velocity through a spiral spring or any elasticmedium. A wave cannot be transmitted through an inelastic softiron spiral. Elasticity is essential in a Tuedium, that it inaytransmit waves com/posed of condensations and rarefactions;and the greater the elasticity, the greater the facility andrapidity with which a medium transmits waves. 154. Air as a medium of tvave-motion. Experiment 4. — Place a candle flame at the orifice a of the long tintube A (Fig. 158) and strike the table a sharp blow with a book near the AIR AS A MEDIUM OF WAVE-MOTION. 189 orifice 6. Instantly the candle flame is quenched. The body of air inthe tube serves as a medium for transmission of motion to the Fig. 158. Is the motion transferred that of a current of air through the tube (aminiature wind), or is it a vibratory motion ? Burn touch-paper i at theorifice 6, so as to fill this end of the tube with smoke, and repeat the lastexperiment. Evidently, if the body of the air be moved along throughthe tube, the smoke will be carried along with it. The candleis blown out as before, but no smoke issues from the orifice is clear that there is no translation of material particlesfrom one end to the other, — nothing like the flight of a riflebullet. The candle flame is struck by something like a jptilseof air, not by a ivind.^ Air is a fluid, and has therefore only volume only waves it can propagate are waves composed of com-pressions and rarefactions. In a previous chapter we haveseen how a wave is the result of a transmission of harmonicmotion or harmonic vibrations through a series of particles. Asound-wave consists of a succession of par
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1895
