人教版小學三年級《24時計時法》課件

24時計時法,年、月、日,聯(lián)系生活：,問題：小紅的一天是怎樣度過的，她都做了什么事情？請你用“早上幾時、中午幾時、晚上幾時，小紅在做什么”這樣的句式說說。,操作活動：,（2）全班交流。,活動：拿出鐘表撥時針，說一說。,要求：（1）2人合作，邊撥邊說說自己的發(fā)現(xiàn)。,（3）回答問題。,（1）從0時到中午12時，經過了（）小時。,（2）從中午12時再到0時，又經過了（）小時。,（3）一天是（）小時。,經過一天，鐘面上的時針轉了（）圈。,12,12,2,24,12,9,1,8,7,6,4,3,2,5,11,10,0,0,半夜12時也叫0時,12,9,1,8,7,6,4,3,2,5,11,10,0,1,2,3,4,5,6,7,8,9,10,11,12,12,9,1,8,7,6,4,3,2,5,11,10,0,1,2,3,4,5,6,7,8,9,10,11,12,12,9,1,8,7,6,4,3,2,5,11,10,13,0,1,2,3,4,5,6,7,8,9,10,11,12,13,12,9,1,8,7,6,4,3,2,5,13,11,10,14,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,12,9,1,8,7,6,4,3,2,5,13,11,10,14,15,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,15,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,15,17,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,15,18,17,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,19,15,18,17,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,19,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,19,15,18,17,20,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,19,20,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,19,15,18,17,21,20,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,19,20,21,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,19,15,18,17,21,22,20,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,19,20,21,22,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,19,15,18,17,23,21,22,20,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,19,20,21,22,23,12,9,1,8,7,6,4,3,2,5,13,11,10,14,16,19,15,18,17,24,23,21,22,20,0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,9,16,17,18,19,20,21,22,23,24,認真觀察：,問題：鐘面上有紅色、藍色兩圈，如果把鐘面上時針走過的一天的時間展開，會是什么樣子呢？,轉化計時法：,問題：上午9時用24時計時法是幾時？下午5時用24時計時法是幾時？晚上9時呢？說一說你是怎么知道的。,第一圈,第二圈,1、用24時計時法表示出下面的時刻,2、17時是下午幾時？23時是晚上幾時？,下午3時上午10時晚上9時下午6時晚上10時下午2時,15時,10時,21時,18時,22時,14時,下午5時,晚上11時,3、用普通計時法表示下面的時刻,6時12時時30分24時16時18時45分,早上6時,中午12時,上午9時30分,下午6時45分,下午4時,深夜12時（0時）,4、這是一個新設郵筒，每天取3次信，早上8時30分第一次取信，以后每隔4小時取一次信。請標出每次取信的時間。,取信時間,第一次：,第二次：,第三次：,8：30,12：30,16：30,你是怎樣想的？說說你的想法？,碧水小學2016年夏季作息時間表,通過今天的學習，你有什么收獲?,同學們：今天的學習開心嗎？,今