A draft of the article "What's in the Universe"

China's lecture notes on the future of the universe in senior high school

Hello, judges and teachers. I am very happy to attend this lecture. The topic of my speech today is "The Future of the Universe", which is a text in Compulsory 5 of Senior Two Chinese in New People's Education Press. Next, I will give this lecture from the following aspects, please give your advice.

First, the goal of knowledge education

1. Know something about cosmology;

2. Understand some characteristics of the speech.

Second, the ability training objectives

1. Learn to hold lectures on popular science to improve the scientificity and standardization of lectures;

2. By comparing with the previous text in this unit, improve the ability of comparative reading.

Third, the goal of moral education infiltration.

Through the study of this paper, students' enthusiasm for exploring the mysteries of the universe is stimulated.

Fourthly, the goal of aesthetic education infiltration.

Guide students to understand the humorous language style of this speech and improve their thinking and language expression ability.

Key points, difficulties, doubts and solutions

Key points:

1. Know something about cosmology;

2. Understand some characteristics of the speech.

Difficulties:

1. Learn to hold lectures on popular science to improve the scientificity and standardization of lectures;

2. By comparing with the previous text in this unit, improve the ability of comparative reading.

Class arrangement

1 class hour

Teaching step

First of all, clear objectives.

1. Know something about cosmology;

2. Understand some characteristics of the speech.

3. Improve the ability of comparative reading by comparing with the text in front of this unit.

Second, overall perception.

1. Introduce a new lesson

In the field of natural science in today's world, I'm afraid Steven will be the first to compete with Einstein. Hawking not only made brilliant scientific achievements, but also deeply infected us with his strong will. Today, we will study one of his speeches, The Future of the Universe (the title of blackboard writing).

Looking up at the bright starry sky, we will be awed and have endless associations and imaginations. Since ancient times, people's speculation and exploration of the universe has never stopped. For example, in Tian Wen, Qu Yuan sent out a series of questions: "Who preached it at the beginning of ancient times? The top and bottom are shapeless, how to test them? ..... nine days, let Ann go? There are many corners, but who knows their number? What is the sky? Twelve points? Sun, Moon and Safety? Li Xing Chen An? Coming from Tanggu, second only to Meng Ying, is self-evident and gloomy. How many miles have you walked? " China's ancient cosmology includes Huntian theory, Gaitian theory and Michelle Ye theory. And the west has Heliocentrism and geocentric theory. However, it was not until the birth of modern cosmology in the 20th century that people made a fundamental breakthrough in their understanding of the universe. The author of this paper is a famous theoretical physicist. He gave a lecture on such a mysterious topic as "the future of the universe" at Cambridge University. What does it inspire us to understand the universe?

2. Introduction to the author

Stephen? Hawking is following Albert? The most outstanding physicist after Einstein. Hawking 1942 was born in Oxford, England. He studied mathematics, physics and cosmology at Oxford University and Cambridge University. Hawking was diagnosed with amyotrophic lateral sclerosis from 65438 to 0963. This disease can cause muscle atrophy, leading to paralysis; It will become more and more difficult to speak until the language ability is completely lost; Patients usually die of pneumonia or suffocation. But the patient's thinking ability, including memory ability, is not affected. The doctor told Hawking that he could only live for two years at most. After a short period of disappointment and depression, Hawking started his cosmological research again. Hawking later made outstanding research achievements in the fields of relativity, "Big Bang" and black holes. Hawking's cosmology book A Brief History of Time: From the Big Bang to the Black Hole, published in 1988, is a landmark bestseller. Hawking has been diagnosed with illness for more than 30 years, but he is still committed to the theoretical study of the origin of the universe and is still working hard for a unified theory. Hawking is currently Lucas Professor of Mathematics at Cambridge University, a position that Sir Newton once held.

Three, the focus and difficulty of learning and the process of achieving the goal.

1. Perceive the text and make clear the overall writing idea of this article.

At the beginning of the speech, the author pointed out that it is very difficult to predict the future, especially the future of the universe. Despite this, scientists are still full of confidence.

In the second paragraph of the text, the author changed the topic and investigated the history of prophecy. Speaking of prophecy, people can't help thinking of ancient witchcraft. Witches use "poison or gas spilled from volcanoes" to "put themselves in a trance" just to add a little mystery. "The real skill lies in explanation". The same is true of modern religious prophecy, which constantly covers up the failure of prophecy with new explanations, such as "counting the list of rescued people first" and so on. So, is the scientist's prediction a temporary "deception" like the ancient prophet? The author points out that "scientific prediction is not necessarily more reliable than that of wizards or prophets", such as weather forecast, "the precise law of objects under extreme conditions" and the working mechanism of the brain. , still lack of accurate judgment. However, "the future of the universe on a very large scale" can still be predicted.

The local motion in the universe may be chaotic, but the universe is predictable on a large scale. The universe is expanding at a high speed, and other galaxies are rapidly leaving us. Cosmic microwave background radiation proves that the expansion of the universe is generally "stable rather than chaotic", because if the expansion rate and average density of the universe are uneven, the temperature of cosmic microwave background radiation from all directions of the universe will not be so consistent. "This shows that the behavior of the universe is simple on a very large scale, not chaotic. So we can predict the distant future of the universe. "

Judging from the current situation, the distance between galaxies in the universe is increasing, but the gravitational attraction between galaxies may reduce the expansion rate. "If the density of the universe is greater than a certain critical value, gravity will eventually stop expanding and make the universe begin to shrink again. The universe will collapse into a big squeeze. " The state before "Big Squeeze" and "Big Bang" is similar, "the density is infinite" and "the laws of physics fail in this state".

In this way, to predict the future of the universe, "the key question is: what is the average density?" If it is less than the critical value, the universe will expand forever. But if it is greater than the critical value, the universe will collapse. "

However, it is not easy to calculate the average density of the universe. The total mass of stars we can see now is less than1%of the critical value; Even if "the mass of gas cloud" is added, it will reach 1% of the critical value at most. But can we come to the conclusion that the universe will expand forever? Not yet. Because there are still many dark matter in the universe, these dark matter are invisible to the naked eye and cannot be directly observed. Black holes are this kind of dark matter, the product of the death of supermassive stars. Hawking's explanation of a black hole is: "A region in time and space, because there is too strong gravity, nothing, even light, can escape from it." Although we can't see the existence of black holes, we can judge their existence by observing spiral galaxies and galaxy clusters: what can make massive galaxies or galaxy clusters revolve around them must be much more massive than these galaxies and galaxy clusters.

The author points out that according to the current observation and research, considering these dark matter, "it is still only about 10% of the critical mass that the universe can collapse again." So there are anthropic principle and inflation theory. The former assumes that there are multiple universes, and we can only understand one of them. The latter thinks that the universe may suddenly change in an unconventional way and quickly change from a tiny scale to a critical state.

In the final analysis, there are only two fates in the future of the universe: continuing to expand or possibly shrinking. It depends on the existing density of the universe, so scientists have to admit that "the universe is actually on the cutting edge" before weighing the weight of the universe, so they should inherit the tradition of wizards or prophets: "Both sides bet on the safe side."

2. Study the text and discuss the problems.

(1) How does the author discuss "the future of the universe"?

Obviously, the author started with ancient witchcraft and modern religious prophecy, which leads to the topic. This shows that it is very serious to talk about the future of the universe from a scientific point of view, and the difference between science and religion is its realistic spirit. Exploring whether the universe continues to expand or is likely to contract is the main part of this speech, and calculating the density of the universe is the key to this main part. The discussion on the critical value of matter density in the universe leads the problem to a deeper level. Finally, two new theories, anthropic principle and inflation theory, are introduced, which reflect the latest exploration in the scientific community. The author talks about dark matter from visible matter, scientific hypothesis from mature theory, and explains the problem thoroughly. Finally, he didn't make a clear prediction, which just shows his rigorous scientific attitude.

(2) How to understand some related discussions in this article?

Obviously, this is a scientific speech, which involves more complicated background knowledge. This knowledge is closely related to the theme of the speech, and if necessary, the content of the speech will appear abstract and thin. For example, the weather forecast and the working principle of the brain compare that the universe is "stable rather than chaotic" on a large scale, that is, chaotic; For example, when it comes to the death (destination) of black holes caused by stars, it seeks theoretical support for the existence of dark matter in the universe; For example, talking about the extreme sensitivity of the existing universe to the initial density leads to the "anthropic principle" and so on. These related expositions either highlight the viewpoint from the opposite side or strengthen the viewpoint from the depth, making the argument rich and colorful.

(3) What are the linguistic features of this speech?

Obviously, the speech is face-to-face communication, and this communication is one-dimensional. If we don't pay attention to the language art of speech, we won't achieve the best expression effect. In addition to rigorous reasoning, this speech is also characterized by humorous language. Humorous language creates a relaxed and pleasant atmosphere with more affinity, which makes the things explained more acceptable to the audience. For example, when talking about the chaos of roulette wheel rotation, the author said that even physicists can't calculate its "number, otherwise, physicists will make a fortune in casinos", which vividly illustrates what chaos is; For example, the last sentence of the article: "So I just inherited the good tradition of those wizards or prophets, and both sides made a bet to show their affirmation." With irony and humor, he took a cautious attitude towards the judgment of the future fate of the universe.

arrange work

Complete Seminar and Exercise 1 and Exercise 2.

Design a

First, guide the design.

1. can be introduced from the attention of ordinary people to the earth where we live, and lead scientists to pay attention to the infinite universe, thus leading to Hawking's "The Future of the Universe". This introduction is intended to emphasize the sense of responsibility of scientists.

2? We can import from the purpose of reading scientific papers and scientific explanatory articles (understanding viewpoints and acquiring knowledge) and directly cut into the basic viewpoints of this paper. This introduction is intended to highlight the reading methods of scientific papers. )

The above two kinds of import should directly cut into the main body of the article without analyzing the structure of the full text.

Second, the process design

1? Process: students read, discuss and communicate, and teachers guide, guide and summarize.

2? Methods: Students discuss freely and teachers guide them.

3? Summary: Hawking's prediction of the future of the universe mainly has the following views:

(1) The expansion and collapse of the universe are related to the average density of the universe. If the average density is less than a certain critical value, it will expand forever. If the average density is greater than the critical value, the universe will collapse and time itself will end.

(2) There should be some invisible dark matter in spiral galaxies and galaxy clusters, and its gravity is enough to firmly grasp the high-speed rotating galaxies and prevent these galaxies or galaxy clusters from flying away.

(3) If the universe continues to expand, five billion years later, the sun will run out of its nuclear fuel and become a white dwarf. After about10 billion years, the stars with solar mass will become white dwarfs or neutron stars, and the stars with greater mass will become black holes.

(4) Particles in a black hole may escape from the black hole at a speed exceeding the speed of light. As long as there is enough time, a huge black hole can "evaporate".

(5) There should be enough dark matter outside the galaxy or cluster of galaxies to make the density reach a critical value, which may eventually lead to the collapse of the universe. But this time must be fifteen billion years later.

4? Experience the humorous language features of this speech.

As a speech about the future of the universe, many pages in the article are serious scientific topics, and many technical terms are used, which makes people feel bored easily. But Hawking's cleverness lies in his use of a lot of humorous language, which makes such an academic speech aimed at explaining scientific principles make people listen carefully in a relaxed and pleasant atmosphere. There are many such languages, such as "fortunately, it seems to take a long time to name." "You can't actually predict these numbers, otherwise, physicists will make a fortune in casinos." "Even if the universe is about to collapse, I can confidently predict that it will not stop expanding for at least ten billion years. I expected that I would not stay in the world at that time, and it would be proved wrong. " "If the inflation theory is correct, the universe is actually on the blade. So I just inherited the good traditions of those wizards or prophets, and both sides made a bet to show their affirmation. "

Original address of Lianshan courseware:/gaoer/37339.htm.