Gilbert light experiments for boys . (). Is it bright? It is darkerthan the paper in the first case andbrighter in the second, because morelight goes through the greased spotthan through the paper. Experiment No. 17. Four can-dles against one. Put four candles2 feet from the greased-spot screenand one candle 1 foot on the otherside (Fig. 30). Trim the wicksuntil the flames are of equal size. Is the greased spot as brightas the paper? It is, because thelight which goes through from oneside is exactly equal to that whichgoes through from the other, thatis, the one candle throws as muchligh
Gilbert light experiments for boys . (). Is it bright? It is darkerthan the paper in the first case andbrighter in the second, because morelight goes through the greased spotthan through the paper. Experiment No. 17. Four can-dles against one. Put four candles2 feet from the greased-spot screenand one candle 1 foot on the otherside (Fig. 30). Trim the wicksuntil the flames are of equal size. Is the greased spot as brightas the paper? It is, because thelight which goes through from oneside is exactly equal to that whichgoes through from the other, thatis, the one candle throws as muchlight on the screen as do the fourcandles. This is explained by the Fig. 29. The spot is bright by trans-mitted light law of intensity men-tioned above. Each ofthe four candles is 2 feetfrom the screen andtherefore throws justone-fourth as much lighton the screen as onecandle does at 1 foot. Experiment No. power of alamp. The candlepower of a lamp is the. Fig. 30. One candle at one foot is equal to four attwo feet GILBERT LIGHT EXPERIMENTS 23
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectscientificrecreation
