Teaching objectives:
Understand the illusion phenomenon at sunset and its reasons.
Learn to see the essence of things through superficial phenomena.
Learn to describe things vividly.
Teaching emphases and difficulties:
Understand the essence of things through phenomena.
How to describe things vividly?
Teaching tools: multimedia.
Instructional design:
(Scroll a few pictures of sunset before class)
Game import, feeling illusion:
Visual games:
Show the following two groups of pictures about visual differences. Students think: Which is longer, the red line or the blue line? Which is bigger, the yellow ball or the deep purple ball in the middle of Figure 2? (Actually, it's the same size)
Conclusion: Many times, we will have illusions or hallucinations about things for various reasons, which will affect our understanding of things. So look at the essence through the phenomenon. There are many such examples in life, such as sunset. Today, let's take a look at the sunset landscape that appears every day.
Go into the textbook and experience the text;
1, enjoy the illusion:
According to a group of pictures about sunset shown before class, students enjoy the beautiful scenery of sunset.
What is the beauty of the sunset? Please talk about colors and shapes, and you can also talk about your own unique findings. Are the characteristics of these sunsets you just discovered real or an illusion? Huang Tianxiang, a scientist, keenly captured this point and wrote his exploration in this article "The Illusion of Sunset". Today, let's follow in his footsteps and approach the sunset together to see the illusion of the sunset!
Hallucination analysis:
Read the text for the first time and grasp it as a whole. (Task: 1. Sketch new words; 2。 Think about the object and genre of the article) Let one student read the first paragraph, half the students read the second to fourth paragraphs, and the other half read the fifth to seventh paragraphs. )
Dredge new words.
Grasp the object of explanation and perceive the content of the text.
This article is an expository one. Truth, as the name implies, the principle of things is an expository text that tells the principle of things and tells the reasons of things in a popular way. The research object of this paper is the illusion of sunset, so the article will talk about the causes of the illusion of sunset.
Read the text again, find out five kinds of hallucinations about sunset and the principle of hallucinations, and complete the table.
Summarize the explanation order of this article: the logical order from phenomenon to essence.
Product illusion:
Read the description of the illusion of sunset in the second paragraph and think about whether each of the following sentences can be modified.
If you have a chance to watch the sunset, it will fascinate you: the sun lies quietly on the western horizon, becoming so big, so deep yellow and crimson; It descends slowly, contracting and flattening as it approaches the horizon.
The sunset scene is beautiful: the sun looks bigger than usual, with yellow or red color, and looks a little flat when it is about to set.
If there are clouds in the sky, you will see a brilliant sunset; There are no clouds all day. Don't forget to look back. You will find a mysterious blue-gray dark arc in the sky behind you, and there is an obvious bright arc outside the dark arc.
Changed to: When there are clouds, there will be a sunset glow in the sky; When there is no cloud, there may be a dark blue-gray arc with a bright arc outside.
The benefits are clear: the original text uses beautiful words, uses anthropomorphic rhetoric and vivid language.
(3) Original sentence: Didn't even our ancients leave the poem "to see the sun, for all his glory, buried by the coming night"?
In other words, we ancients also left a poem "to see the sun, for all his glory, buried by the coming night".
The first sentence is a rhetorical question, which emphasizes that the ancients also had this kind of emotion and has a heavy meaning; The second sentence is a general affirmative sentence, which is only an objective explanation and has no focus.
People like to watch the sunrise and admire the spectacular scene when the sun rises.
People like to watch the sunrise and enjoy the spectacular scene at sunrise.
The first sentence uses a double negative, emphasizing that everyone who watches the sunrise will be amazed; The second sentence is a general affirmative sentence, which lacks this emphasis.
4. Inspiration: What inspiration did you get after learning this article?
Look at the picture and think:
Is the pencil broken? (refraction phenomenon)
Are there three children standing next to Yao Ming?
(Several basketball players with a height of1.80m and above took a group photo with Yao Ming (background) (reference).
Students discuss and clarify:
1. Learn to see the essence of things through phenomena;
2. Seeing is not necessarily believing, so learn to know the truth;
3. We should observe life carefully and respect scientific facts;
……
Get out of the textbook and expand;
Quiz:
1. does not explain why the sun seems to get bigger at sunset. Combined with the article "The Sunset Becomes Bigger", please summarize the reasons for "The Sunset Becomes Bigger".
Teacher's message: Real things are often not necessarily beautiful, while beautiful things are often covered with false coats. What we see is only an illusion, but we are still happily addicted to it and don't want to wake up. But one day, I will wake up, some people lament, some people are sad, some people are numb, and some people are strong. We study this article not only to let you see the essence of every illusion, but also to let you live poetically. When the illusion fades and the truth comes out, you can be as normal and indifferent as watching the sunset every day. Because, you are already happy in beauty, besides, tomorrow, there will be a new sun rising.
Fourth, homework:
1, the text ends after analyzing the sunset phenomenon and principle. It seems that the structure is incomplete. Please try to add an ending to the text according to your previous understanding.
2. Watch the sunrise after class and write a descriptive paragraph.
The sunset is getting bigger and bigger.
If we take a sunset and a noon sun with a set camera and compare them, we will find that they are exactly the same size, so why does the sunset we see seem to be bigger?
It turns out that when our eyes observe an object, the size we feel depends not only on the actual size of the object itself, but also on the distance, background and brightness of the object itself.
Let's talk about "background" first. It means that under certain conditions, people will have illusions about objects. An object looks bigger in some small objects, while an object looks smaller in some big objects. At night, the sun will set from the horizon. Because the horizon is far away from us, the trees and houses in the distant background are very small, which makes people unable to see clearly. When the sun sets on the horizon, it looks big. At noon, the sun hangs high in the vast sky, which is very small compared with the tall trees and houses near the earth.
Let's talk about the "light seepage phenomenon". The white figure we see is larger than the black figure of the same size, which is called "light penetration" in physics. When the sun goes down, the surrounding sky is dark, so the sun appears bright, and the light leakage phenomenon is not obvious, so it appears small. At noon, the surrounding sky is very bright. In contrast, the brightness difference between the sun and the background is not so big, which is why we look more sunset.
It is also related to the structure of the eyes. Another reason why the sun is bigger at night than at noon is that the setting sun is low. When we observe, our eyes are straight up, and the lens in the eyeball is in a normal state, with small protrusions and large focal length. The image of the sun on the retina through the lens is also very large. At noon, when we observe the sun, we need to look up. Due to the limitation of the bending degree of the head and neck, sunlight cannot directly enter the human eye. We looked at the sun sideways. In order to get a clear image on the retina, the lens will involuntarily bulge, making its focal length smaller and the image formed on the retina smaller, so when we look up, we will feel that the sun is getting smaller.
In addition, it is also because of the refraction of light. We look at the sun in the morning, because the angle is low, and the air layer through which the light passes is thicker and denser, which will produce refraction. At noon, the air layer is thin, the density is low, and the light is direct, which looks bigger.