Science for beginners . muchless surface than the many small drops had. We might per-haps say that this crowds the electricity and increases itsintensity. When that process goes far enough an electricdischarge takes place. This discharge is the lightning objects like trees, chimneys, spires, etc., are most likelyto be struck, and any object much taller than its surround-ings should be avoided during a thunderstorm. Kite flyingin or near a thunder storm is dangerous. LOCAL STORMS 185 The lightning of a distant thunderstorm at night oftenmakes a beautiful display if not hidden by othe
Science for beginners . muchless surface than the many small drops had. We might per-haps say that this crowds the electricity and increases itsintensity. When that process goes far enough an electricdischarge takes place. This discharge is the lightning objects like trees, chimneys, spires, etc., are most likelyto be struck, and any object much taller than its surround-ings should be avoided during a thunderstorm. Kite flyingin or near a thunder storm is dangerous. LOCAL STORMS 185 The lightning of a distant thunderstorm at night oftenmakes a beautiful display if not hidden by other is called heat lightning, is usually the reflected light-ning of a distant storm. Thunder is caused by lightning. A flash of lightning heatsthe air along its path suddenly with an intense heat. Thiscauses a sudden expansion of the air. Almost instantly theair cools and contracts again. This sudden expanding andcontracting of the air along the path of the flash producesthe sound waves which we call Fig. 142.—The layers of hail stones. Figs. 1, 2, and 3 show the for-mations of hailstones having five, seven and nine layers, respectively,outside the central nucleus. The stippled dark portions represent snow. 197. The Thunderstorm; Hail.—Hail is usually made upof alternate layers of clear ice and 01 cloudy ice or hail forms is not fully understood. One of the prin-cipal theories may be explained from Fig. 139. Supposethat the uprush of air in a portion of such a storm carries adrop of rain up into the colder part of the cloud near H,where the raindrop mixes with snow, freezes, then falls backtoward K, receives a layer of water which immediately freezesto its icy surface; is then carried aloft for another coating ofsnow; and so on until the stone becomes too heavy and fallsto the ground. Hailstones may be split with a sharp knife,showing the layers (Fig. 142). As many as 20 to 25 lay-ers have sometimes been found. Damaging hail is rare inmost plac
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