About the moon

First, the influence of solar radiation on the earth.

1, solar radiation and solar constant

Question: What is solar radiation?

Reading: The sun constantly radiates energy in the form of electromagnetic waves, which is called solar radiation.

Question: What is electromagnetic wave?

Discussion: All objects in nature transmit energy in the form of electromagnetic waves all the time. Radio waves, infrared rays, visible light, ultraviolet rays, X rays and gamma rays are all electromagnetic waves. Their wavelengths are different, and their characteristics and functions are also very different. Electromagnetic waves and mechanical waves travel in different ways. The speed of electromagnetic waves is 300,000 kilometers per second.

Question: What is the solar constant?

Reading pictures: Analyze the conditions that define the solar constant: ① Under the condition of the average distance between the sun and the earth, ② at the upper boundary of the earth's atmosphere, ③ under the direct sunlight, within the area of 4 1 cm2, ⑤ 1 min. At present, the value of the solar constant is 8.16j/(cm2 min).

Q: What is the purpose of introducing the solar constant?

Discussion: mainly calculate the energy of solar radiation reaching the earth.

2, the source of solar radiation energy

Question: What is the temperature on the surface of the sun?

Answer: The sun is a fiery fireball, and its surface temperature is as high as 6000K degrees. Explain the relationship between "Kelvin temperature scale" and "Celsius temperature".

Question: How much solar radiation energy reaches the earth's surface?

Discussion: ① The energy transmitted to the earth by solar radiation per minute is about equivalent to the heat generated by burning 400 million tons of bituminous coal; One in two billion solar radiation reaches the earth.

Problem: The high temperature on the surface of the sun and the energy transmitted to the earth fully illustrate the enormous energy of solar radiation. How is such a huge solar radiation energy formed?

Discussion: Solar radiation mainly comes from the nuclear fusion reaction inside the sun.

Narrator: knowledge about nuclear fusion reaction. The composition of the sun is mainly hydrogen and helium. In the environment of high temperature and high pressure, four hydrogen atoms fuse into 1 helium atom, and the nucleus loses a small part of its mass and converts it into huge energy. This is the nuclear fusion reaction. This kind of reaction is basically the same as that of some nuclear weapons made by human beings and some nuclear power plants in theory.

4H →He+ energy

Q: Will this nuclear fusion reaction in the sun end one day?

Discussion: Yes. But at present, human beings don't have to worry about this, because although the sun loses about 4 million tons of mass per second due to nuclear fusion reaction, it only consumes about 0.03% mass in the last 5 billion years of its existence. The sun is currently in its youth, and it is precisely because of this that the sun can provide endless energy for the earth, and the earth can breed life in a stable energy environment.

3. The influence of solar radiation on the earth.

Question: What kind of influence does solar radiation have on the earth?

Discussion: the sun brings light and heat to the earth, which makes life appear on the earth …

Reading: summarize the influence of solar radiation on the earth in concise language.

(1) Solar radiation is a factor in the formation and change of geographical environment.

Tell: the difference between geographical environment and cosmic environment, and briefly introduce the knowledge about geographical environment to students.

Question: How does solar radiation promote the change of geographical environment?

Discussion: Without solar radiation, there would be no weather phenomena such as wind and rain on the earth (according to the specific situation, students can talk about the causes of wind and rain), there would be no rivers on the land ... Without solar radiation, there would be no life on the earth ... Without the activities of wind, water and life, the geographical environment would not be transformed, and it would be dead year after year.

(2) Solar radiation is the energy basis for maintaining life activities.

Question: If the sun disappears one day, can there still be life on the earth? Can humans still live?

Discussion: Unless human beings have evolved to get rid of solar radiation. According to the current way of human existence, the life activities of human beings and almost all living things are inseparable from solar radiation. "Everything grows on the sun", the sun shines, and everything shows great vitality, that is, human beings and creatures are directly enjoying the solar radiation; Coal, oil and natural gas used in our life are all fixed solar energy in geological history; Of course, with the progress of science and technology, human beings have also learned to use solar energy to generate electricity to solve the problem of energy shortage.

Look at the picture: "Utilization of solar energy".

Second, the influence of solar activity on the earth.

1, the concept of solar activity

Q: What is solar activity?

Reading: Frequent or even drastic changes in the surface of the sun are generally called solar activities.

2. Types of solar activity

Q: What are the main types of solar activities?

(1), sunspots.

Question: What are sunspots?

Reading: There are often some black spots on the surface of the sun, called "sunspots".

Look at the picture: the "sunspot" picture.

Question: How are sunspots formed?

Reading: Because its temperature is lower than other parts of the sun's surface, it looks darker.

Question: Is there any regularity in sunspot activity?

Reading: Yes. The period of sunspot activity is about 1 1 year.

Look at the picture: Correlation between Sunspots and Annual Precipitation.

Narrator: The number and size of sunspots are signs of the intensity of solar activity.

2. Flash.

Q: What is a flare?

Reading: Sometimes patches that suddenly increase and brighten appear on the surface of the sun, which is called "flare".

Look at the picture: The Explosion Process of a Big Flare.

Narrator: A flare takes only a few minutes to dozens of minutes from the beginning to the climax. However, a flare will release the energy equivalent to about 6543.8+000 trillion-ton hydrogen bombs. These include strong radio waves, a lot of ultraviolet rays, X-rays, gamma rays and high-energy charged ion streams.

Q: Is there any regularity in flare activity?

Reading: The active period of flare is basically the same as that of sunspot, which is 1 1 year.

Narrator: Flare explosion is the strongest manifestation of solar activity.

3. The influence of solar activity on the earth.

Narrator: Solar activity changed the amount of solar radiation energy reaching the earth, so it had a far-reaching impact on the geographical environment.

Question: What is the effect of solar activity on the earth?

Activity: Summarize through reading, and the teacher will give necessary explanations.

Conclusion: ① Influence on the Earth's ionosphere; ② Influence on the Earth's magnetic field; ③ Impact on the Earth's climate.

Look at the picture: "The correlation between sunspots and annual precipitation" and answer the question.

1, the correlation between precipitation and sunspot relative number at different latitudes is as follows: ① Before 50-600 n, 19 10, the correlation between precipitation and sunspot relative number was negative, and after 19 10, it was positive; ② The precipitation of 60-700 N is negatively correlated with the relative number of sunspots; ③ The precipitation at 50-600 N is positively correlated with the relative number of sunspots.

2. The annual variation cycle of sunspots and precipitation is about 1 1 year.

Summary: The influence of sunspots on the earth fully shows that the geographical environment is not isolated, but is deeply influenced by the cosmic environment. We should strengthen the observation and research on solar activities in order to minimize the possible adverse effects of solar activities.

Third, the moon phase and its changes

Transition: Once upon a time, the myth and legend of "the Goddess Chang'e flying to the moon" inspired people's imagination; Once upon a time, "I don't know what year it is tonight"? Throughout the ages, the moon has left many beautiful reverie for mankind. Now we know that the moon is the only natural satellite of the earth and the closest celestial body in the universe. It has a close relationship with the earth, and the dream of landing on the moon has long been realized.

The most impressive thing about the moon is its change.

1, the concept of the moon phase

Question: What is the moon phase?

Reading: The different visual shapes of the moon are called moon phases.

2, the cause of the moon phase

(1), the moon itself is neither luminous nor transparent, but it can reflect sunlight and shine.

(2) The formation of the moon phase is mainly related to the positions of the sun, the earth and the moon.

Look at the picture: The Movement of the Moon, first look at the orbit of the earth around the sun, the orbit of the moon around the earth and the orbit of the moon with the earth around the sun, and then ask questions in the textbook.

Discussion: the positional relationship between the sun, the earth and the moon.

(1), the position of the moon, just between the earth and the sun. At this time, the side of the moon illuminated by the sun is facing away from the earth, which is invisible to human beings. Visually, the moon disappears from the night sky The moon at this time is called "new moon" or "new moon".

(2) When the moon is in position B, the right half of the moon is illuminated, which visually means that people in the night hemisphere of the earth can see the illuminated moon in the right half. The moon at this time is called "the first quarter moon".

When the moon is in position C, the earth is just between the moon and the sun. At this time, the side of the moon illuminated by the sun is facing the night hemisphere of the earth, indicating that the moon is all illuminated like a silver plate. What is the name of the moon at this time? Quot look "or" look at the moon ".

(4) When the moon is in position D, the left half of the moon is illuminated, which visually means that people in the night hemisphere of the earth can see the illuminated moon in the left half. The moon at this time is called "the last quarter moon".

Look at the picture: "Moon Phase" and complete the table below.

The approximate time (lunar calendar) when the name of the moon phase appears, the position of the day, the earth and the moon is related to the visual shape.

The new moon or the first day is roughly in a straight line, with the moon in the middle. Invisible

On the seventh and eighth days of the first quarter moon, the earth and the moon are roughly at right angles, and the moon is semicircular in the west of the earth. I saw it in the western sky in the middle of the night, and the moon was facing west.

The full moon or the moons on 15 and 16 are roughly in a straight line, with the earth in the middle. Visible all night, a bright moon

On the 22nd and 23rd of the last quarter, the earth and the moon are at right angles, and the moon is semicircular in the east of the earth. At midnight, the moon faces east and can be seen in the eastern half of the sky.

Song formula: Moon changes into Song.

The new moon on the first day is invisible only because it is trapped in the sun and the earth.

On the eighth day of the seventh lunar month, the half moon faces west.

When the full moon comes out on the 15th and 16th, the earth shoulders the sun and the moon.

Twenty-two, three and the last quarter of the moon, the moon faces east until midnight.

Look at the picture: Moon Phase. Understand the shape and causes of "waning moon (new moon)", "protruding moon" and "waning moon".

3, the use of the moon phase

Question: What influence does the moon have on people's lives?

Reading: People use the phase of the moon to make calendars, such as the lunar calendar or lunar calendar, and according to the phenomenon that the two strings and four phases of Wang Shuo are separated by about 7 days, they evolve into weeks. It can be seen that the change of the moon phase plays an extremely important role in the measurement of time.

After-school activities: observe the moon phase.