Teacher Recruitment Interview Elementary School Science "Comparing the Amount of Water"

Hello, you can refer to the following teaching design for primary school science "Comparing the Amount of Water".

Analysis of teaching materials

1. Status and function of teaching materials

Since students are new to science classes and experimental design in the third grade, this class attempts to take advantage of students’ strong It can stimulate students' curiosity to design experiments and lay a solid foundation for experimental design in science courses.

2. Teaching objectives

1. Through the activity of comparing more water and less water, let students realize the variety of comparison methods.

2. Compare liquid amounts through a variety of methods, and measure liquids using standard and non-standard units of measurement.

3. Important and difficult points in teaching:

Use a variety of methods to compare the amount of water in different containers, and learn to correctly use a measuring cylinder to measure and compare the amount of water.

Academic Analysis

Third-year students have strong curiosity and a strong desire for knowledge, but they lack life experience, their logical thinking is not clear, and they are not very clear about designing experiments.

Teaching strategies

Discussion method, experimental method

1. Introduction

Teacher: There are three different bottles here, each containing Some water, guess which bottle has more water?

Prediction: 1. Three bottles of water have the same amount (No. 3 is big, but the water is short, and No. 2 and No. 1 are small, but the water is high)

Teacher: They are all the same as him Do you have the same idea?

2. Bottle No. 1 contains more water. (Because of Gao)

Teacher: Is there anyone who supports him?

3. Bottle No. 2 has more water (because although it is not as big as bottle No. 3, it is taller, and although it is shorter than bottle No. 1, it is wider than bottle No. 1)

Teacher: Your reasons are very good. Do you have any other ideas?

Bottle 4 and No. 3 have more water (because they are bigger)

(If you can only guess which bottle has more water but cannot tell the reason, teacher: It seems that you are just guessing. , so who can make an informed guess? )

Teacher: Everyone’s opinions are not unanimous, so how can we compare the amount of water? Let’s study it together in this class. (Show the topic blackboard: Compare the amount of water) (Courseware 1)

2. Teaching process

1. Compare who has more water and who has less water

Teacher: This Who has more of the three bottles of water and who has less? Do you have any good way to compare? Please discuss it in groups and complete the experimental design sheet. Teachers inspect and master experimental methods

Prediction: 1. Find three identical bottles (cups) and see which bottle (cup) has the highest water content.

The teacher asked: Do you think this method is feasible? If it is possible, what should we pay attention to during the experiment? Do other groups have any good suggestions?

Student 1: Pour slowly to prevent pouring, which may affect the experiment.

Teacher: Do you agree?

Student 2: Do not pour water onto the wall of the cup, because water on the wall of the cup will also affect the experiment.

Teacher: Does your group accept his suggestion?

Student 3: If the difference is very small and we cannot judge it with our eyes, we also need to use a ruler.

Teacher: This is a good method. Is there anything I need to pay attention to when using the ruler?

Student 1: The chosen ruler is longer than the water

Teacher: I noticed the range of use, great!

Student 2: The ruler is straight, but the bottom of the bottle is curved. I don’t think the measurement can be accurate.

Teacher: He raised a very good question, so is there any way we can solve it? (Can you use other things to help?)

Student 1: You can stick notes.

Student 2: You can underline.

Student 3: Pour the water into a flat-bottomed cup

Teacher: That’s a good idea.

Teacher: Could you please complete your experimental design based on the results we just discussed?

Teacher: Are there any different methods? (Your group didn’t raise their hands just now. Did you choose a different method from them?)

2. Compare the weight of water

Teacher: How to compare?

Student 1: Weigh it with your hands. The bottle that feels heavier will have more water in it.

Teacher: Do you think it’s okay?

Student 1: No! Because the bottles are different.

Teacher: What should we do?

Student 1: Pour them all into the same bottle.

Teacher: Is this okay?

Student 1: Not necessarily! This is because our human feelings may not be so accurate. If it is just a little different, we may not feel it, so we need a weighing instrument.

Teacher: Your thoughts are really complete. In science, the most commonly used tool for weighing is a balance. We can use a balance to complete this experiment. Have you ever learned how to use a scale? (No) Given this experimental tool, can you complete the experiment and obtain the experimental results?

Sheng: No.

Teacher: So in the process of designing experiments, we should choose the simplest experimental plan that you are most confident about.

Teacher: Do you want to try it yourself? Ask each group to follow the experimental plan you designed, and the group leader will go to the teacher to get the materials.

Teacher: What did you find?

Student: Bottle No. 2 has the most water, bottle No. 1 has the second most water, and bottle No. 3 has the least water.

2. Introducing the graduated cylinder

Teacher: We found through experiments that No. 2 has the most water, but how can we know how much more? We need a unified standard and accurate measuring instrument. Let me introduce a new tool to you, which is a measuring cylinder. (Show the measuring cylinder) The usage and precautions of the measuring cylinder are on page 74 of the book. Please read it carefully. Who can introduce the measuring cylinder to you?

Student 1, there are scales

Student 2: There are many densely packed ones.

Student 3: There are numbers

Teacher: What are the largest number and the smallest number you found?

Student answer

Teacher: This is the range that this measuring cylinder can measure.

Student 3: There is a mark of ml

Teacher: This is the volume unit of liquid, milliliters. There is also a liter, which you often see in life.

Courseware 3)

What should we pay attention to when using a measuring cylinder? (Courseware 2)

Student 1: Place it flat on the table.

Teacher: Why?

Student 1: Because it is made of glass and I am afraid it will be damaged.

Teacher: In addition to paying attention to safety, is there any other reason why we must put it flat on the table?

Student 1: In order for us to use it better, otherwise the water surface will tilt and we will not be able to read its indications

Teacher: Do you agree? Now that we are talking about readings, what else should we pay attention to during the reading process? Who found it?

Student: The concave liquid surface between the line of sight and the horizontal plane is level

Teacher: So what should we do specifically? (The teacher does three reading methods: looking up, looking down, and looking down) Which one do you agree with? Everyone must look straight at the concave surface of the water surface during the reading process, so that the number we read will be accurate. (Show courseware 4)

Teacher: Now ask the leader of each group to come to the front and bring a measuring cylinder. Please use the measuring cylinder to measure the volume of water in the three bottles, and record the measurement results in the scientific paper. In the table on page 74 of the book.

It is recommended that you pour the measured water into the sink on the experimental table. Pay attention to safety during the measurement process. Both the measuring cylinder and the sink should be handled with care.

Teacher: Which group can tell you how many milliliters each bottle of water contains?

Default: If the data of each group is different, ask why everyone’s measurement results are different?

It may be that water was spilled during the experiment, water was left on the wall of the bottle, etc.

3. Application Development

Teacher: Do you know how much 5ml of water is? Can you use the measuring cylinder in your hand to measure?

Sheng: No. (Emphasis on the scope of use of the measuring cylinder)

Teacher: In this class, we not only learned to use different methods to compare the water in three bottles, but also got to know the measuring cylinder, learned to use the measuring cylinder, and used it to compare We have found out how many milliliters more water there is in the three bottles. We will continue to use it in future studies.