What are meridians and parallels? How to determine meridians and parallels? Meridians and parallels of the Ural Mountains. Summary of the lesson "Degree network on the globe and maps

Intersection points earth's axis with the surface of the globe are called poles (North and South). The Earth rotates once around this axis in 24 hours.

A circle is drawn at the same distance from the poles, which is called the equator.

Parallel - lines conventionally drawn on the surface of the Earth parallel to the equator. The parallels on the map and the globe are directed to the west and east. They are not equal in length. The longest parallel is the equator. The equator is an imaginary line on earth's surface, obtained by mentally dissecting the ellipsoid into two equal parts (Northern and Southern hemispheres). With such a dissection, all points of the equator are equidistant from the poles. The plane of the equator is perpendicular to the Earth's axis of rotation and passes through its center. In total, there are 180 meridians on Earth, 90 of them are north of the equator, 90 are south.

The parallels of 23.5° north and south are called tropical circles or simply tropics. On each of them, once a year, the midday Sun is at its zenith, that is, the sun's rays fall vertically.

The parallels of 66.5° northern and southern latitudes are called polar circles.

through the North and South Pole circles are drawn, meridians are the shortest lines conventionally drawn on the surface of the Earth from one pole to another.

The prime or prime meridian was drawn from the Greenwich Observatory (London, UK). All meridians have the same length and the shape of semicircles. In total, there are 360 ​​meridians on Earth, 180 to the west of zero, 180 to the east. Meridians on the map and globe are directed from north to south.

To accurately determine the location of any object on the surface of the earth, one line of the equator is not enough. Therefore, the hemispheres are mentally separated by many more planes parallel to the plane of the equator - these are parallels. All of them, like the plane of the equator, are perpendicular to the axis of rotation of the planet. You can draw as many parallels as you like, but they are usually drawn at intervals of 10-20 °. Parallels are always oriented from west to east. The circumference of the parallels decreases from the equator to the poles. At the equator, it is the largest, and at the poles it is zero:

Length of arcs of parallels

When the globe is crossed by imaginary planes passing through the axis of the Earth perpendicular to the plane of the equator, large circles are formed - meridians. Translated into Russian, the word "meridian" means "midday line". Indeed, their direction coincides with the direction of the shadow from objects at noon. If you go all the time in the direction of this shadow, you will definitely come to the North Pole. Meridians are the shortest line conventionally drawn from one pole to another. All meridians are semicircles. They can be drawn through any point on the surface of the Earth. They all intersect at the poles. The meridians are oriented from north to south. The average arc length of 1° meridian is calculated as follows:

40,008.5 km: 360° = 111 km

All meridians are the same length. The direction of the local meridian at any point can be determined at noon by the shadow of any object. In the Northern Hemisphere, the end of the shadow always shows the direction to the north, in the Southern - to the south.

The image of meridian lines and parallels on the globe and geographical maps is called a degree grid.

Geographic latitude- this is the distance of any point on the earth's surface to the north or south of the equator, expressed in degrees. Latitude is north (if the point is located north of the equator) and south (if south of it).

Geographic longitude is the distance of any point on the earth's surface from the prime meridian, expressed in degrees. To the east of the zero meridian will be eastern longitude (abbreviated: east longitude), to the west - western (west longitude).

Geographic coordinates - geographic latitude and geographic longitude of a given object.

>> degree network, its elements. Geographical coordinates

§ 3. Degree network, its elements. Geographical coordinates

Navigating the map and finding the exact location of geographical objects on the surface of the Earth allows degree network, or a system of lines of parallels and meridians.

Parallels(from the Greek parallelos - letters, going side by side) - these are lines conventionally drawn on the surface of the Earth parallel to the equator. Parallels on the map and globe you can spend as much as you like, but usually on educational cards they are carried out with an interval of 10-20 °. Parallels are always oriented from west to east. The circumference of the parallels decreases from the equator to the poles.

Equator(from lat. aequator - equalizer) - an imaginary line on the earth's surface, obtained by mentally dissecting the globe with a plane passing through the center of the earth perpendicular to the axis of its rotation. All points on the equator are equidistant from the poles. The equator divides the globe into two hemispheres - Northern and Southern.

Meridian(from lat. meridians - midday) - the shortest line conventionally drawn on the surface of the Earth from one pole to the other.

table 2

Comparative characteristics meridians and parallels

Geographic poles(from Latin polus - axis) - mathematically calculated points of intersection of an imaginary axis of rotation of the Earth with the earth's surface. Meridians can be drawn through any point on the earth's surface, and all of them will pass through both poles of the Earth. Meridians are oriented from north to south, and all have the same length (from pole to pole) - about 20,000 km. Average length of 1° meridian: 20004 km: 180° = 111 km. The direction of the local meridian at any point can be determined at noon by the shadow of any object. In the Northern Hemisphere, the end of the shadow always shows the direction to the north, in the Southern Hemisphere - to the south.

degree, or cartographic, network is used to determine geographic coordinates points on the earth's surface - longitudes and latitudes - or mapping objects by their coordinates. All points of a given meridian have the same longitude, and all points of a parallel have the same latitude.

Geographic latitude is the arc of the meridian in degrees from the equator to given point. So, St. Petersburg is located in the Northern Hemisphere, at 60 ° northern latitude(abbreviated N), Suez Canal - at 30° N To determine the geographic latitude of any point on a globe or map is to determine which parallel it is located on. Any point south of the equator will have south latitude (short for S).

Geographic longitude is the magnitude of the parallel arc in degrees from the prime meridian to the given point. The initial, or zero, meridian is chosen arbitrarily and passes through the Greenwich Observatory, located near London. To the east of this meridian, eastern longitude (east longitude) is determined, to the west - western longitude (west longitude) (Fig. 10).

The latitude and longitude of any point on the Earth make up its graphical coordinates. So, geographical coordinates Moscow - 56°N and 38° E. d.

Maksakovskiy V.P., Petrova N.N., Physical and economical geography peace. - M.: Iris-press, 2010. - 368 pp.: ill.

Work with text and work with the atlas p.22.

Students are divided into groups and answer questions.

- What are meridians?

What do they look like and why are they called that?

- The length of the meridians.

– What are parallels?

Why are they called that, what do they look like?

is the length of the parallels.

Teacher: Guys, what did you learn about parallels?

Students response.

Parallels are lines that are conventionally drawn along the surface of the earth parallel to the equator. Do you remember what the equator is? Show on the map and on the globe. At each point, the parallel points east and west. Parallels are circles that decrease in length from the equator to the poles. Do you remember what a pole is? The longest parallel is the equator. Its length is 40,000 km. All parallels are circles, the length of which decreases from the equator to the poles. On the map of the hemispheres, parallels are curved lines (arcs), and the equator is a straight line.

Meridians. Translated into Russian, the word "Meridian" means "midday line". Its direction coincides with the direction of the shadow from objects at noon. If you go all the time in the direction of this shadow. Then you will definitely come to the North Pole, and in reverse side- to the South.

Meridians are the shortest lines conventionally drawn on the surface of the earth from one geographic pole to another. All meridians are semicircles, converge at the poles and have the same length. On the physical map hemispheres the median meridian is a straight line, and the rest are arcs.

Teacher: Parallels and meridians are drawn through a certain number of degrees.

Work with maps and atlases.

Teacher: Find the equator on a physical map and on a globe. On the contour map mark the equator. He shares Earth into two hemispheres (Northern and Southern). The parallels are measured from the equator. Parallels 10, 20, ... 80 degrees of the Northern or Southern Hemisphere.

Label the parallel 10 degrees of the Northern Hemisphere and 20 degrees of the Southern Hemisphere.

Parallels are signed in a circle on the map of the hemispheres and on the meridian (zero) on the globe.

Teacher: By agreement between the countries prime meridian considered to be the meridian passing through the Greenwich Observatory in the suburbs of London. Therefore, this meridian is also called the Greenwich meridian. On the map, it is shown with a bolder line than the rest of the meridians.

Select the prime meridian on the map. It divides the globe into two hemispheres (Western and Eastern). The meridians are signed at the equator.

We complete task 43 p. 36.

Teacher: What are parallels and meridians for?

Students: For orientation, determine and indicate the location of various geographical objects on the surface of the Earth.

Teacher: Correctly. The ancient Greek scientist Eratosthenes, who lived in 276-194. BC e., for the first time proposed to apply conditional lines on images of the earth's surface - parallels and meridians.

Determination of directions by meridians and parallels.

Teacher: What do we know. What directions show conditional lines.

Students: Parallels - West, East.

Meridians - north, south.

Teacher: At each point, the parallel is perpendicular to the meridian. Therefore, if you stand on the ground facing north, in the direction of the meridian, spread your arms to the sides, then they will indicate the direction of the parallels, i.e. West East.

The main and intermediate sides of the horizon are determined by meridians and parallels.

1. In what direction is Cairo from St. Petersburg?
2. In what direction is Moscow from St. Petersburg?
3. In what direction is the Red Sea from Moscow?

With the help of conditional lines, you can determine not only directions, but also indicate the position of parts of territories, objects. To determine, for example, the northern and southern parts of Australia, you need to put a pointer on the map along a parallel that runs approximately in the middle of the mainland. To the north of the pointer will be the northern part, and to the south - the southern. How do you define Western and Eastern Australia.

“And cities and countries, parallels, meridians flash by,” is sung in a song called “Globe”. But if the cities and countries indicated on the globe exist in reality, then the parallels and meridians are imaginary objects marked on the globe or map solely for ease of reading and orientation.

The best assistant in orientation is a coordinate system, which must have a reference point. The Earth (however, the same principle can be applied to any other planet or its satellite - it would be, for what) such an imaginary "zero point" was determined using poles - points through which the axis of its rotation passes. The North Pole is rather a mathematical object, it is located in the Arctic Ocean, but the South Pole is a very real point on land, on the mainland called Antarctica, you can get there, you can take pictures there - if you are not afraid to freeze, of course ...

So, at an equal distance from these very poles, in the middle between them, there is an imaginary "belt" of the Earth, dividing the planet in half, into the Northern and Southern hemispheres. Most of the continents are in one of them, and only Africa is in both. So, the equator is the “reference point”, which is considered zero latitude. Imaginary lines drawn on a map and globe parallel to the equator are called parallels.

Latitude is measured in degrees, 1 degree is approximately 111 km. It is considered from the equator (the farther from it, the more number: equator - 0 degrees, poles - 90 degrees). To the north of the equator, degrees of northern latitude are counted, to the south - to eastern longitude. There is another way of designation: south of the equator, latitude is written with a minus sign (this can be understood: those who created geographical science lived in the Northern Hemisphere, and their shirt, as you know, is closer to the body).

All this, of course, is wonderful, but ...

Let us recall the novel by J. Verne "Children of Captain Grant". The heroes who went to help Captain Grant and his companions, who survived the shipwreck, knew that their location was thirty-seven degrees eleven minutes south latitude. To find them, the heroes had to travel around the world along this parallel.

To avoid such difficulties, there is a second coordinate - longitude, and on the map it is indicated by meridians - lines connecting the poles.

If we wanted to choose a parallel for the longest world travel, it would certainly be the equator. But choosing a meridian for such a thing will not work - they are approximately the same, so choosing a starting point among them is not so easy, therefore for a long time in this regard, there was discord: in France, the Parisian meridian was taken as a reference point, in Russia - passing through the Pulkovo observatory, etc. Finally, in 1884, on International Conference in Washington, they adopted a single reference point - the meridian passing through the axis of the transit instrument of the observatory in Greenwich - administrative district London on the right bank of the Thames. It is from the Greenwich meridian that the western and eastern longitudes are calculated (the heroes of the mentioned novel were not lucky: the longitude in the note was washed away with water).

The number of kilometers in one degree of longitude is more difficult to name than in relation to latitude: it is not the same for different latitudes- at the equator, too, 11 km, and the closer to the poles - the less).

The degree grid consists of a system of lines (parallels and meridians) and their coordinates. In reality, these lines are absent on the earth's surface. They are carried out on maps and plans for mathematical calculations, determining the location of an object on the surface of the Earth.

Rice. 1. Parallels and meridians

The direction of the meridian coincides with the direction of the shadow at noon. Meridian- a conditional line drawn on the surface of the Earth from one pole to another. The magnitude of the arc and circumference of the meridian is measured in degrees. All meridians are equal, intersect at the poles, have a north-south direction. The length of one degree of each meridian is 111 km (divide the circumference of the Earth by the number of degrees: 40,000: 360 = 111 km). Knowing this value, it is not difficult to determine the distance along the meridian. For example, the length of the arc along the meridian is 20 degrees. To find out this length in kilometers, you need 20 x 111 = 2220 km.

Meridians are usually labeled at the top or bottom of the map.

The countdown of meridians starts from the zero meridian (0 degrees) - Greenwich.

Rice. 2. Meridians on the map of Russia

Parallels

Parallel- a conditional line drawn along the surface of the Earth parallel to the equator. The direction of the parallel points to west and east. The parallels are drawn not only parallel to the equator, but also parallel to other parallels, they are different in length and do not intersect.

The longest parallel (40,000 km) is the equator (0 degrees).

Rice. 3. Equator on the map

The length of one degree of each parallel can be seen at the border of the map.

Length of 1 degree parallels

Rice. 4. Parallels (a) and meridians (b)

Drawing parallels and meridians. Determination of their directions

Parallels and meridians can be drawn through any place on the earth's surface. Parallels and meridians can be used to determine the main and intermediate sides of the horizon. According to the meridians, the directions "north", "south" are determined, along the parallels - "east", "west". Intersecting, parallels and meridians form a degree network.

Bibliography

Main

1. Starting Course Geography: Proc. for 6 cells. general education institutions / T.P. Gerasimova, N.P. Neklyukov. – 10th ed., stereotype. – M.: Bustard, 2010. – 176 p.

2. Geography. Grade 6: atlas. – 3rd ed., stereotype. – M.: Bustard, DIK, 2011. – 32 p.

3. Geography. Grade 6: atlas. - 4th ed., stereotype. – M.: Bustard, DIK, 2013. – 32 p.

4. Geography. 6 cells: cont. cards. – M.: DIK, Bustard, 2012. – 16 p.

Encyclopedias, dictionaries, reference books and statistical collections

1. Geography. Modern illustrated encyclopedia / A.P. Gorkin. – M.: Rosmen-Press, 2006. – 624 p.

Materials on the Internet

1. Federal Institute pedagogical measurements ().

2. Russian Geographic Society ().