Core knowledge points of geography review in Hunan college entrance examination

A summary of the knowledge system of geography in college entrance examination

Unit 1 The Earth is in the Universe

[knowledge point]

I. The cosmic environment of the Earth

1. Celestial body: the existing form of matter in the universe, collectively referred to as celestial body. According to its material composition, mass and motion law, it can be divided into stars, nebulae, planets, satellites, comets, meteoroids and other main types. The most basic types of celestial bodies are stars and nebulae, and their differences are as follows:

Stars are composed of hot celestial bodies and spherical celestial bodies with great mass and self-luminescence; All the stars are constantly moving and changing. Because they are far away from us, their relative position seems to be fixed. The sun is the nearest star to the earth.

A celestial body consisting of gas and dust that looks like a cloud; Compared with stars, nebulae have the characteristics of large mass, large volume and low density, and the main component is hydrogen.

2. Celestial sphere: an imaginary sphere with an observer as the center and an infinite radius. When explaining the position and motion of celestial bodies, people regard the projection of celestial bodies on the celestial sphere as themselves.

3. Constellation; In order to understand the stars, the celestial sphere is divided into several regions, called constellations, and the whole day is divided into 88 constellations. There are three constellations around the North Celestial Pole: Ursa Major, Ursa Minor and Xianhou Constellation, which can be seen all year round in the middle and high latitudes of the northern hemisphere. In early September, near the mid-latitude 2 1 in the northern hemisphere, some constellations such as lyra, swan and skyhawk can be seen near the zenith.

4. Celestial system: All celestial bodies in the universe are moving, and the moving celestial bodies attract each other to form different levels of systems. (as shown in the figure below)

5, the general situation of the sun (compared with the earth)

The main components of the average distance between the sun and the earth are radius, mass, volume density and gravity acceleration.

1500,000 km (8 minutes optical path) Earth's hydrogen and helium radius 109 times (700,000 km) Earth's mass is more than 330,000 times, Earth's volume130,000 times, Earth's density10.3 million times and Earth's density is 28 times.

6. The external material structure of the sun: The outside of the sun is the atmosphere, which is divided into three layers from inside to outside: the photosphere, the chromosphere and the corona. All activities in the solar atmosphere are always called solar activities. Sunspots and flares are the main signs of solar activity, and the period is 1 1 year.

The sign of solar activity, the degree of occurrence, and the influence of solar activity on the earth.

When there are more sunspots and flares in the sunspot photosphere (1), the intense radio will interfere with the radio communication on the earth. (2) The charged particle stream ("solar wind") thrown by the solar atmosphere will interfere with the magnetic field on the earth and produce a "magnetic storm"; Charged particles rush into the polar upper atmosphere at high speed and collide with the thin atmosphere to form aurora)

Flare, prominence chromosphere

"solar wind" corona

7. Source of solar energy: The nuclear fusion reaction takes place in the center of the sun at high temperature and high pressure, that is, four hydrogen atoms fuse into a helium nucleus. In the process of nuclear fusion, the sun loses some mass and releases a lot of energy.

8. Solar system: A celestial system consisting of the sun, planets and their satellites, asteroids, comets, meteoroids and interplanetary matter. The sun is the central celestial body of the solar system; In the solar system, other celestial bodies revolve around the sun under the action of the sun's gravity (as shown in the figure below).

9. The motions of the nine planets have three characteristics: regional, isotropic and nearly circular.

10 and nine planets can be divided into three categories according to their structural characteristics: terrestrial planets, giant planets and distant planets.

1 1. Conditions for the existence of life on the earth: (1) Proper distance between the sun and the earth and proper rotation period make the earth have suitable temperature and liquid water, which is beneficial to the existence of biological substances; (2) The earth has proper volume and mass, and its gravity can absorb all kinds of gases in the atmosphere, and in the long evolution process, it has formed an atmosphere suitable for biological breathing.

Second, the earth and its movement

1, the shape and size of the earth

Several data representing the size of the earth

The earth is an irregular ellipsoid with slightly flat poles and slightly bulging equator, with a polar radius of 6356.8 kilometers.

The equatorial radius is 6378. 1km.

The average radius is 637 1 km.

The circumference of the equator is about 40,000 kilometers.

The surface area is about 5 1 100 million square kilometers.

2. Latitude and longitude net: the latitude and longitude interweave to form a latitude and longitude net. People can use the latitude and longitude net to determine the position and direction of any point on the earth's surface and measure the distance between two points.

(1) Latitude and longitude (2) Latitude and longitude

Characteristics of several important warp yarns

① Meridians represent the north-south direction ② All the meridians are equal in length ③ Two opposite meridians form a warp coil, and any warp coil can divide the earth into two hemispheres equally. ① 0 meridian (prime meridian) is the dividing line between east longitude and west longitude. ② The longitude lines of 20 west longitude and160 east longitude are the dividing lines between the eastern and western hemispheres. ③ Longitude 180, international international date line.

Characteristics of several important weft yarns

① Latitude indicates the north-south direction; ② Each latitude forms a circle; ③ The equator is the largest latitude circle; From the equator to the poles, the latitude circle is getting smaller and smaller, and it narrows to a point at the poles. ① The 0 parallel (equator) is the dividing line between the northern and southern hemispheres. ② The Tropic of Cancer (23 26) is the southernmost and northernmost dividing line of direct sunlight; It is the dividing line between tropical and temperate zones. ③ The south and the Arctic Circle (66 34) are the dividing lines between the infinite day and the polar night; It is the dividing line between the cold zone and the temperate zone.

3. Comparison between the rotation and revolution of the earth motion (1).

Rotation and revolution of motion form

The direction from west to east (counterclockwise from the North Pole and clockwise from the South Pole) is consistent with the direction of rotation, both from west to east.

Period ① sidereal day: The real period of the earth's rotation, which rotates 360 degrees and takes 23: 56 minutes and 4 seconds. ② Solar Day: People usually say that "one day" rotates 360 59', which takes 24 hours. It takes one year to make a revolution. Astronomy usually says that a year is 5: 48: 46 on 365, which is a year of return.

Speed ① Angular velocity: about every hour 15, every 4 minutes 1, except that there is no angular velocity at the poles, it is the same everywhere. ② Linear speed: With the change of latitude, the equator is the largest, and gradually decreases towards the poles. The position of 60 degrees north and south latitude is about half of the equator, and the polar wireless speed. ① Angular velocity: 1. ② Linear speed: about 30 kilometers per second on average, with perihelion fast and apohelion slow.

Geographical significance ① The alternation of day and night ② The difference of local time ③ The horizontally moving object is biased, with the northern hemisphere leaning to the right and the southern hemisphere leaning to the left ④ It affects the shape of the earth and makes it a slightly flat ellipsoid of revolution. ① Changes in the height of the sun at noon ② Changes in the length of day and night ③ Changes in the four seasons ④ Morphology of the five zones.

(2) local time; Because the earth is constantly rotating, the time in the morning and evening is different in different places with different longitudes, and the time in the east is earlier than that in the west. Because of different longitudes, this time is called local time. Longitude every 15, local time difference 1 hour, longitude every 1, local time difference 4 minutes.

(3) Time zones and international date line: The division of time zones is to unify the standard of time, and the world is divided into 24 time zones every hour according to the longitude 15 of the earth from west to east. In order to avoid the confusion of dates, international date line adopted longitude 180 as the international international date line according to international regulations. Each time zone is unified with the local time of the central meridian, because the time difference between adjacent time zones is 1 hour. On both sides of the date line is the change of date. The time in East and West is the same, but the date is one day apart.

(4) Orbit of revolution: the route that the earth moves around the sun, which is called orbit of revolution, also called the ecliptic. This is a nearly circular ellipse, and the sun is at the focus of the ellipse. At the beginning of every year 1 month, the earth moves to the position closest to the sun, which is called perihelion; At the beginning of July every year, the earth moves to the farthest position from the sun, which is called apohelion.

(5) Huang Chijiao; The revolution and rotation of the earth are carried out at the same time, that is, the revolution is carried out while rotating. Revolution has two characteristics: (1) The included angle between the earth axis and the orbital plane remains unchanged at 66 34'. (2) The tilt direction of the earth's axis is always the same, and the north pole always points to the vicinity of Polaris. Because of the above two characteristics, there is an included angle between the orbital plane and the equatorial plane of the earth, that is, the intersection angle between yellow and red. The current declination angle is 23 26' (as shown in the figure below).

(6) Four seasons change: Four seasons refer to the cycle of spring, summer, autumn and winter on the earth. Astronomically speaking, summer is the season with the longest day and the highest sun in a year. Winter is the season with the shortest days and the least sunshine in a year; Spring and autumn are the transition between winter and summer. In climate statistics, March-May is generally divided into spring (northern hemisphere, the same below), June-August is divided into summer, September-165438+1October is divided into autumn, and12-February is divided into winter. The seasons in the northern and southern hemispheres are opposite.

(7) the division of five districts; People divide the earth into tropical zone, southern temperate zone, northern temperate zone, southern frigid zone and northern frigid zone according to the amount of solar heat and sunlight exposure (as shown in the following table and figure).

Tropical north-south temperate north-south cold zone

The range between the Tropic of Cancer and the Tropic of Cancer and between the Tropic of Cancer and the Antarctic Circle; The Antarctic circle is between the Tropic of Cancer and the Arctic Circle to the South Pole; Arctic Circle to North Pole.

Sun exposure: you can directly expose yourself twice a year (once on the line), without direct exposure, and there is no extreme day and night phenomenon. The sun is oblique, and it is extremely day and night.

At most, it gets less sunlight and heat than tropical areas and more than cold areas.

[Review Guide]

The knowledge in this chapter can be summarized into two parts: the first part is the cosmic environment of the earth, and the second part is the law of the earth's movement and its geographical significance. We should firmly grasp these two aspects when reviewing.

First of all, the cosmic environment of the earth.

1. The astronomical knowledge involved in this part is extremely rich and extensive. First of all, we must clarify the basic concepts of various celestial bodies, because this is the basis for understanding the relationship between various celestial bodies. When reviewing, we should grasp the connotation of various celestial concepts through analysis and comparison, and further understand the relationship between celestial systems on this basis.

2. Astronomical knowledge mostly belongs to macroscopic phenomena, and it is difficult for people on earth to see the true colors of these things completely and truly. Therefore, we should pay special attention to observation when reviewing. Only in this way can we understand the concepts of various celestial bodies and celestial bodies systems on the basis of a lot of perceptual knowledge.

3. When reviewing the knowledge about the sun, we should make two points clear: (1) solar radiation is the source of energy on the earth; (2) The influence of solar activity on the earth. To review the knowledge about the solar system, we should make two points clear: (1) The moderate position of the earth in the solar system is an important condition for the existence of life on the earth; (2) From the characteristics of the movements and structures of the nine planets, we know that the earth is just an ordinary planet in the solar system.