EstimatingDistances（估算距离）.doc

英文版估算距离设计者：Chad Dahl学生级别：2，3科目：数学/测量序言：“看地图”并非仅仅是看着地图，找出你在地图上的位置；有时，为了搞清从甲地到在乙地需要花费的时间，你不得不在地图上估算出两地的距离。很久以前，人类就学会了估算距离的方法。设计本节课的目的是为了让学生们知道一些估算距离的方法，活学活用数学知识。教学目标：1 使学生们利用教师示范的方法来估算一段较短的距离；2 让学生们发明出另一种估算距离的方法。背景资料：这节课最好在教室外进行；如果把学生分成小组进行活动，效果会更好；应先从较短距离开始，逐渐过渡到较长的距离。教学材料：尺子；铅笔；卷尺；纸；粉笔教学过程：1 向学生提问：从他们站立的地方到教师所指的某物的距离是多少？2 告诉学生，可以用脚步来测量距离；3 划一条线，让学生们站在线的后边，以正常的步幅走出两步；4 用尺子丈量从线条到学生脚后跟之间的距离；5 分别把这些代表距离的数字除以2，就是每个学生迈出一步所走过的距离，把它们在纸上记录下来；6 让学生们数一数：从自己站立的地方走到教师先前指定的某物处，一共走了多少步？7 记下自己的步数，再把它与表示自己步幅的数字相乘，即得出结果。例如，约翰每走一步是3英尺，他走到目标物所在地点，一共走了16步，那么，163=48，约离目标物的距离是48英尺；8 再让学生估算从站立点到另一目标物的距离；9 问学生：为什么这种估算距离的方法很重要？教学评估：在活动开始前，选定一段距离，并用卷尺量出这段距离的实际尺寸，然后让学生们进行估算，看看结果是否一致；让学生们想出另一种估算距离的方法来。Chinese versionEstimating Distances An AskERIC Lesson Plan Submitted by: Chad DahlEndorsed by: Don Descy, Mankato State University Date: May 14, 1997 Grade Level(s): 2, 3 Subject(s): Mathematics/Measurement Description: Map reading is more than just looking at maps and finding where you are on the map. Sometimes you have to estimate a certain distance on a map in order to know how long it will take to get from point A to point B. Estimating distances has been with us for a long time. Students should know some methods in estimating distances and use math as a real use. Goals: The students will get a better understanding on how people estimate distances and the process in estimating short distances. Objectives:1. The students will be able to estimate a short distance by using the method I demonstrate to them.2. The students will invent another method in estimating distances. Background Information: This activity is best used outside. Small groups would be better than the whole class at once. Start out with short distances and then with longer distances. Concepts: Students will be able to perform algebraic problems while estimating distances. Materials: measuring stick pencil tape measure paper chalk Procedure: 1. Ask the students what they think a certain distance is between where they stand at and the object you point out. 2. Tell the students there is a way to estimate distances by their own pace count. 3. Have the students stand behind a line and have them take 2 normal steps. 4. Measure the line to the heel of the student with the yard stick. 5. Then divide that number by 2 and write it down on a sheet of paper. This will be the students average pace count. 6. Have the students count the number of paces it takes to get to the certain object. 7. Take that number and multiply it by the students pace count. For instance: Johns pace count is 3 feet. It took 16 paces for John to reach the certain object. 16 paces multiplied by 3 feet = 48 feet for an estimated distance. 8. Repeat the steps with another object. 9. Ask the students why they think this would be important. Assessment: Pick the a distance and measure before the act