单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,*,The most important invention-Light,Introduction,The First Electric Light,Made in 1809 by,Hunphry Davy,this is called the,electric arc.,Late,The American,Charles Francies Brush,manufactured,some carbon arcs.,The Inventor,Thomas Edison,experimented with thousands of different materials,eventually produced a,bulb,that could glow for over 1500 hours.,汉弗莱戴维爵士（法拉第的老师）,k,电弧,manufactured,mnjfkt 制造，加工（manufacture的过去式）,carbon arcs,电 碳弧,bulb,blb 电灯泡,There are three kinds of light.,1.Incandescent lamp(白炽灯)：,a.Incandescent lamp （白炽灯）,b.Tungsten halogen lamp（卤钨灯）,c.Halogen lamp （卤素灯）,.,2.High intensity discharge lamp-HID（气体放电灯）,a.Fluorescent lamp（荧光灯）,b.Sodium lamp （钠灯）,c.Metal halide lamp（金属卤化物灯）,.,3.Others.,a.E,lectrodeless,L,amp（高频无极灯）,b.L,ight,E,mitting,D,iode（发光二极管）,.,In the early 19th century，,a,British chemist,made the first arc lamp in the world by using 2000,cells(电池）,and 2 carbon rods.,But this kind of light is too strong,，,it cannot be used in the house but only in the street.,In,1879,By Thomas Edison-an American inventor,The temperature of the,filament,:3000,A,verage,life span,:,1000,h,Its a lamp which ranks first in the production,of the world.,But many countries are trying to stop using it,because of its heavy pollution.,Incandescent lamp,（,白炽灯,）,filament,flmnt 灯丝,life span,寿命,Compare to,Incandescent,l,amp,this kind of lamp,has,longer life span(4000h)and,h,igh,er,light efficiency,.,It It is often used in the meeting room,t,he exhibition hall,and the stage.,T,ungsten,H,alogen,L,amp,（,卤钨灯,）,light efficiency,光效率,F,luorescent,L,amp（,荧光灯,，,俗称日光灯,）,Long,life span,:2500h3500h,H,igh light efficiency,G,ood color rendering,The temperature of the filament,:,1000,color rendering,显色性,S,odium,L,amp,(,钠灯,),The highest l,ight efficiency,.,Fog permeability,Life span:20000h,Be used in roads,airports,terminals,highways,etc.,Fog permeability,透雾性,E,lectrodeless,L,amp,（,高频无极灯,）,Very long life span:40000h80000h,Energy saving,Brighter,So,it is often used in some places which have,higher requirements for safety.,Such as,tunnels,subway stations and factories.,tunnels,隧道,L,ight,E,mitting,D,iode（发光二极管）,Same features as e,lectrodeless,l,amp,but,more energy saving.,It is secure when it w,ork under the,low,thermal voltage,.,And its surface temperature less than 60,.,low,thermal voltage,低热电压,What will happen if our world have no light?,The ordinary light,it is a witness of human conquest of the night.,Thats all,thank you!,