Night and day and night, are two different problems.Reflect the day and night the earth as an opaque ball, relative to the sun in the solar system backward relationship;Day and night change reflects the earth as a movement of the ball, in the process of sports being constantly adjust itself to the dorsal part of the sun.We think simply replace causes only comes down to the earth's rotation, day and night for geography teachers, especially the non-professional and full-time middle school geography teachers to study and grasp Gao Chuzhong about this part of the content of teaching material, has caused some difficulties.Therefore, it is necessary to discuss.Generally call day and night, it is to point to a day, 24 hours 3 minutes and 56 seconds, often said to 24 hours.In more than one day, from day to night again by the reciprocating alternately, night into day is night
晝夜和晝夜更替，是兩個不同的問題。晝夜反映的是地球作為壹個不透明的球體，在太陽系中相對於太陽的背向關系；晝夜更替反映的是地球作為壹個運動著的球體，在運動過程中不斷調整著本身對於太陽的背向部位。我們認為簡單地把晝夜更替成因只歸結為地球自轉，對於地理教師，尤其是非專業而專職的中學地理教師鉆研和把握高初中有關這部分內容的教材，造成了壹定的困難。因此，有必要進行探討。
壹般所說的晝夜，是指壹個太陽日，即24小時3分56秒，通常說成24小時。在壹個以上的太陽日中，由白晝到黑夜再由黑夜變成白晝的交替往復，就是晝夜更替。