Teacher Luo's lecture also gave a good suggestion to the front-line teachers: it is also a good lesson to teach according to the textbook and return the classroom to the students. He took a class in Grade One as an example:
Ask questions in the context of textbooks, and then let students think independently, and get various methods to solve the problem of "how many radishes have been pulled" Then the teacher just asked, "Do they have the same method?" Then students communicate independently, analyze the similarities and differences of various methods, communicate and contact, and try to practice after students fully communicate and express; Because it is the first time for students to contact the vertical style, Teacher Luo finally designed the question "Do you have any curiosity and questions about the vertical style?" Keep your children curious. He believes that behind curiosity are innovative ability and critical questioning. The purpose of this question is to cultivate students' critical thinking.
It is a comprehensive process to analyze this teaching process with Bloom's classification of educational objectives, from recognizing, understanding and analyzing topic information to asking questions, and then comparing and analyzing different methods involved in understanding and analysis in classification, and then students integrate knowledge connotation and communicate internal relations. Trying practice belongs to the application level, and evaluation can also be introduced. Finally, whether students can keep critical spirit and ask questions also belongs to the evaluation level. In this way, most of the time, students are constantly questioning, comparing, analyzing and evaluating, thus effectively training students' higher-order thinking.
The teaching focus of finding defective products is to let students go through the process of comparison-guess-verification, and seek the best strategy for finding defective products with a balance, which includes two main points: one is to divide the items to be tested into three parts, and the other is to find out the defective products as quickly as possible.
The original teaching of this course mostly contains two examples, Example 1 and Example 2. For the first part of the example 1, "Can you try to find out?" This problem is very simple to handle, such as asking students to raise their hands to answer. After students answer with scales, they begin to teach how to find out the defective products with scales and how to draw pictures to express them.
I think the class time here should also be returned to students, so that students can fully think about what methods are available, and then optimize the methods and expressions. So, I'm going to spend two hours teaching this course, leaving enough time.
I directly gave the students five minutes to think independently, such as 1. In group communication, only the group is required to sum up ideas and judge whether it is feasible. After class, group activities should be arranged in the order from simple to complex, which can stimulate students' group thinking and keep students' thinking training at a high evaluation level. But the students still gave me many surprises:
When students report on the stage, they need to teach the ideas of the group students to other students, and they need to re-conceive the methods in their minds and analyze how to express them clearly, which belongs to the analytical level of classification methods. Who are the students who didn't speak on the stage? I put forward two listening tasks:
The first task belongs to the understanding level, and the second question belongs to the evaluation level. Next, surprises continue:
Student 1 Introduction to finding with a balance: First, take out two bottles and put them at both ends of the balance. If it is unbalanced, the rising end means lighter, which means three bottles are missing. If it is balanced, change the bottle and weigh it again, and find the bottle that is less.
Student 2 added: Don't weigh it any more. If it is balanced, the remaining bottle must be the one that is missing, because there are only three bottles in total, and the two bottles have the same weight, but the difference is less.
The method is optimization, from weighing one by one to learning to reason.
Student 1 introduces the "water adding method": pour the same volume of water into three bottles, and the bottle with low water level is the one with less water.
Student 3 retorted that if you pour water into the bottle, the calcium tablets will melt and disappear. Can't tell which water level is low?
Student 4 refutes student 3. Although the calcium tablet has melted, its volume has not changed, and it will not disappear because of melting. The water level of the bottle filled with less will still be low.
This method not only jumps out of the convention but also integrates the previously learned volume knowledge. I think this class time has finally been wasted.
Student 5 added: You don't need to pour 3 bottles, just 2 bottles. If the water level is the same, the bottle is gone.
Application of previous reasoning method
Student 6 added: This method is actually the same as the balance method. As long as you judge two bottles, you can infer.
The connection between communication methods. Students already have the best strategy in mind, but they are still looking for more possibilities.
Student 7 added: You can also pour out a number one by one.
I asked: How many bottles should I count?
Student 7 thought for a moment: Just count two bottles. If they are different, the bottle with less quantity is the one you are looking for. If there are two bottles with the same quantity, the rest is the one with less.
Student 8: If the label says how many tablets there are in a bottle, it is possible to find the bottle that is missing by directly counting one bottle.
……
The teaching goal required in the teaching reference is to "infiltrate the optimization idea, feel the diversity of problem-solving strategies, and cultivate the ability of observation, analysis and reasoning", which is fully reflected in the classroom. Because students are willing to spend time, they have enough time to think, reason, evaluate and optimize. After class, a child who failed in all the grades came up to me and said weakly, teacher, in fact, you can know which bottle is missing just by looking at which bottle has been unscrewed, so you don't have to bother and waste water. After listening, I almost picked her up with no excitement.
Of course, there are still many shortcomings in this class. In order to ensure that all the students are listening carefully when communicating with each other in class, I may ask the students to answer questions by randomly selecting people to answer them, so as to ensure the students' attention and to test whether the students understand this part.
Come on, dare to return the classroom to the students first, and then try to optimize the classroom organization and problems. I will continue to explore.