中学示范课—运动与平衡(最终)分析

1、STEM Lesson Balance and MotionSTEM示范课示范课-运动与平衡运动与平衡Balance and Motion Lesson运动与平衡示范课This STEM lesson could come before or during a science unit of study about center of gravity, balance, and motion. 本节STEM课可以出现在科学学科中关于重力、平衡和运动的单元的最初或中间教学时。Lesson objective is to engage students in activating prior kn

2、owledge or checking for understanding about center of gravity. 课程目标：回顾关于重心的先备知识或检查学生对重心概念的理解。Students are in groups of four to facilitate communication and collaboration. 学生将以4人小组形式进行合作与沟通。 Engage: Question 引导性问题引导性问题How do these objects defy gravity? 这些物体是这些物体是怎样怎样摆脱地心引力的？摆脱地心引力的？HOW IS THIS POSSIB

3、LE?怎么会发生这样的现象？How do these How do these objects objects defy defy gravitygravity? ?这些物体是怎样摆脱地心引力的？这些物体是怎样摆脱地心引力的？CENTER OF GRAVITY 重心重心Average location of the weight of an object.一个物体的重量的平均位置。A perpendicular line can indicate its symmetry.一条垂直的线可以表明物体的对称性。When in line with its base, the object will

4、be in balance. 当物体的重心在竖直方向的投影落在物体的支撑面内或支撑点上，物体将处于平衡状态。BALANCE平衡Explore: Inquiry 探索：做调查How does balance work? 平衡状态是怎样产生的？BALANCE ACTIVITY关于“平衡”的活动Finding the center of gravity. 找到重心。Determining the affect of the size of the base and the location of center of gravity on stability. 确定支撑面大小和重心位置对稳定性的影响。

5、EXPLORE BASE, STABILITY & CENTER OF GRAVITY探索支撑面/基底、稳定性、和重心Use the clothespins to lower center of gravity and balance on tip or edge (base). 用晾衣夹来降低物体的重心，用晾衣夹来降低物体的重心，并且以并且以“角角”或或“边边”为支撑面来保为支撑面来保持平衡。持平衡。Where is the center of gravity? 重心在哪？重心在哪？How did the clothespins affect stability? 夹子如何影响稳定性

6、？夹子如何影响稳定性？Balance the shape flat on your finger (base). 将扁平状的物体放在一根手指将扁平状的物体放在一根手指( (支撑面支撑面/ /基底）上，并使之保基底）上，并使之保持平衡。持平衡。Note the location of center of gravity. 记录重心位置记录重心位置How stable is the object? 物体的稳定性如何？物体的稳定性如何？Balance the shape on any edge (base). 将任意边作为支撑面将任意边作为支撑面/ /基底来基底来保持平衡。保持平衡。Did the

7、center of gravity change? 重心位置变了吗？重心位置变了吗？How stable is the object? 物体的稳定性如何？物体的稳定性如何？Explain: Findings and Discussion解释：发现与讨论 What did we learn about balance when working with shapes?通过研究物体的不同形状，我们学到了哪些关于平衡的知识？WHAT MAKES OBJECTS STABLE?物体保持稳定性的因素The size of its base area. 支撑面的大小The larger the base

8、are of an object, the more stable the object. 物体的支撑面越大，越稳定。LOCATION OF CENTER OF GRAVITY重心位置The position of an objects center of gravity affects its stability. 物体的稳定性受重心位置影响。The lower the center of gravity, the more stable the object. 重心越低，物体越稳定。A double decker bus A double decker bus is stable if i

9、s stable if the the center center of gravity is of gravity is low. low. 如果一辆双层巴士的重心低，则稳定性好。如果一辆双层巴士的重心低，则稳定性好。 If each bus on the right has passengers inside, which is the most stable? 如果乘客都在巴士内的右侧，谁的稳定性最好？ Passengers only on the lower level 下层的乘客 Passengers only on the upper level 上层的乘客 Passengers

10、equal on both levels 上下层乘客的稳定 性相同CENTER OF GRAVITY & BASE重心与支撑面 How does the location of the center of gravity affect each crane?重心位置怎样影响起重机？ Which is showing a stable counterweight? Which is unstable?哪个起重机稳定性、平衡性好？哪个起重机不稳定？Elaborate: Apply New Learning深层次的探究：运用新知识How can you get a pencil to bal

11、ance on its tip? 怎样使铅笔用顶端/尖端保持平衡？WHAT WE KNOW?我们知道哪些信息/知识？ The place on which an object balances is called the balance point. “平衡点”： 物体在这一点上（或这一位置上）能够保持平衡。 Objects with a high center of gravity are not stable and tip over. 重心高的物体不稳定并且会翻倒。 To increase stability, the center of gravity should be as low

12、 as possible. 为了增加稳定性，重心要尽可能的低。 The base can be small if the center of gravity is low and directly beneath it. 如果重心低或者重心低于支撑面，那么支撑面可以小一些。USING WHAT WE KNOW TO SOLVE A PROBLEM ：How can you balance a pencil to stand on its tip? 用已学到的知识解决问题用已学到的知识解决问题：怎样使铅笔用顶端：怎样使铅笔用顶端/尖端保持平衡？尖端保持平衡？Engineering Design

13、Engineering Design Process (EDP) Process (EDP) 工程设计过程工程设计过程Step 1: What is the problem? Can a pencil stand on its tip on its own?第一步：问题是什么？怎样使铅笔用顶端/尖端保持平衡？Step 2: Think about a possible solution, discuss with your partner.第二步：想一个可行的方法，并与搭档讨论。Step 3: Plan your design and draw your ideas.第三步：设计方案并且画出想

14、法。USING WHAT WE KNOW TO SOLVE A PROBLEM ：How can you balance a pencil to stand on its tip? 用已学到的知识解决问题：怎样使铅笔用顶端用已学到的知识解决问题：怎样使铅笔用顶端/尖端保持平衡？尖端保持平衡？Repeat steps 4-6 Repeat steps 4-6 to improve your to improve your designdesign. . 重复第四步到第六步来改进你的模型。重复第四步到第六步来改进你的模型。Step 4: Create and construct a working

15、 model.第四步：建模。Step 5: Experiment and test your model.第五步：做实验并测试模型。Step 6: Can you improve your model?第六步：能改进你的模型吗？Findings 发现发现Communicating your reasoning. 将你的推理将你的推理论证与知识联系起来。论证与知识联系起来。How do we explain how a pencil can balance on its tip?我们如何解释：铅笔怎样用顶端铅笔怎样用顶端/尖端保持平衡？尖端保持平衡？Where is the approximat

16、e center of gravity? 重心大概在哪里？Where is its base support? 支撑面/支撑点在哪里？How were you able to lower its center of gravity? 你怎样使铅笔的重心下移？How did the placement of the clothespins affect balance? 晾衣夹的位置如何影响铅笔的平衡？Partners pair with another pair to make a Partners pair with another pair to make a group of group of four to communicate reasoning.four to communicate reasoning.两对学生组成一个四人组，讨论两对学生组成一个四人组，讨论/ /交流想法。交流想法。Think about other opportunities you have to test center of gravity: 想一想其他需要测重心的场景：Calder Artwork: Creating mobiles or stabiles. 考尔德的作品：动态雕塑或固定雕塑。Sports: Importance of center of balanc