&fourteen. Parallels and meridians

The points of intersection of the earth's axis with the surface of the globe are called the poles (North and South). Around this axis, the Earth makes one revolution in 24 hours.

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

Parallel - lines conventionally drawn along the surface of the Earth parallel to the equator. The parallels on the map and globe are directed west and east. They are not equal in length. The longest parallel is the equator. Equator - an imaginary line on the earth's surface, obtained by mentally cutting an ellipsoid into two equal parts (Northern and Southern hemispheres). With such a cut, all points of the equator are equidistant from the poles. The equatorial plane 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 north of the equator, 90 - south.

The parallels between latitudes 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.

Parallels 66.5 ° north and south latitude are called polar circles.

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

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

For precise definition 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 equatorial plane, are perpendicular to the planet's axis of rotation. You can draw as many parallels as you like, but usually they are drawn at intervals of 10-20 °. Parallels are always oriented from west to east. The circumference of parallels decreases from the equator to the poles. At the equator, it is the largest, and at the poles it is equal to zero:

Length of arcs of parallels

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

40,008.5 km: 360 ° = 111 km

The length of all meridians is the same. 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.

The image of the lines of meridians and parallels on the globe and geographical maps called the degree grid.

Geographic latitude is the distance of any point on the earth's surface 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 prime meridian there will be east longitude (abbreviated: e), to the west - west (w).

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

Remember: What is called the equator? What is the length of the earth's equator? What points on Earth are called geographic poles?

Keywords:equator, parallels, meridians, prime meridian, hemisphere, degree grid, geographic position.

1. Parallels. Have you already remembered that e k w a to r is a line conventionally drawn on the earth's surface at the same distance from the poles. He divides the globe into the Northern and Southern Hemispheres (Fig. 42).

Rice. 42. Hemispheres of the Earth. What separates the Western and Eastern, Northern and Southern hemispheres?

Parallels are lines conventionally drawn on the surface of the Earth parallel to the equator. The word "parallel" indicates the position of this line relative to the equator: all points of one parallel are at the same distance from the equator. As you can see on the globe in the form of a parallel - a circle, their length decreases from the equator to the poles. The largest parallel is the equator. The parallel can be drawn through any point on the earth's surface. Each parallel is directed from west to east (Fig. 43).

Rice. 43. Parallels. Rice. 44. Meridians.

Meridians. The shortest lines, conventionally drawn on the surface of the Earth from one pole to another, are called meridians (Fig. 44). The direction of the meridian at any point on the earth's surface is most simply determined through the direction of the shadow from objects at noon. Therefore, the meridian is also called the midday line (Fig. 46). Translated from Latin into Russian, the word "meridian" means "midday line".

Fig. 46. The meridian line coincides with the direction of the shadow from objects at noon.

The meridians indicate the exact direction from north to south. At each point, the meridian is perpendicular to the parallel, which is why they form a right angle with each other (90 °). Therefore, if you face north, that is, in the direction of the meridian, and spread your arms to the sides, they will indicate the direction of the parallel.

Like a parallel, a meridian can be drawn through any point on the earth's surface.

One of the meridians is conventionally considered to be the initial, or zero. According to the international agreement of 1884, the Greenwich meridian, passing through the Greenwich Observatory in London, is considered the initial one. The prime meridian divides the globe into two hemispheres - Western and Eastern (Fig. 42).

3. Degree grid. On the globe and maps, meridians and parallels are drawn through the same number degrees. For example, after 10 0 or 15 0. (Find these symbols on the globe and map). Crossing, parallels and meridians form a degree grid on the globe and maps (Fig. 45).

Rice. 45. Degree grid.

* On a globe, parallels and meridians intersect at right angles. When these angles on the map are greater or less than the right angle, this indicates distortions of angles and directions, and hence the shape of objects. On the globe, all meridians have the same length, and the length of the parallels decreases from the equator to the poles, which corresponds to reality. Violation of this on the map indicates a distortion of distances, and, consequently, areas.

1. What is called a parallel? Meridian? Degree grid? 2. Into which hemispheres does the equator and the prime meridian divide the earth? In which hemispheres is your area located?

3 * Rewrite Table 2 in a notebook and fill it out (write the answer instead of the question).

Table 2.

Degree grid

Practical work.

1. Find any meridian on a globe or on a map of hemispheres and determine which continents and oceans it crosses from south to north. 2. Show any parallel and determine which continents and oceans it crosses from west to east.

LATITUDES AND MERIDIANS

Almost everyone is familiar with the "mysterious lines" on maps and globes representing latitude (parallels) and longitude (meridians). They form a gridded coordinate system by which any place on Earth can be pinpointed - and there is nothing mysterious or difficult about it. Latitude and longitude are coordinates that define the position of points on the Earth's surface.

Two places on Earth are determined by its rotation around its own axis - these are the North and South Poles. On globes, the pivot is the axis. The North Pole is in the middle of the Arctic Ocean, which is covered sea ​​ice, and researchers in the old days reached this pole on a sleigh with dogs (it is officially believed that the North Pole was discovered in 1909 by the American Robert Perry).

However, since the ice moves slowly, the North Pole is not an actual object, but a mathematical object. The South Pole, on the other side of the planet, has a permanent physical location on the continent of Antarctica, which was also discovered by land explorers (Norwegian expedition led by Roald Amundsen in 1911). Today both poles can be easily reached by plane.

Halfway between the poles, at the "waist" of the Earth, there is a large circle, which is represented on the globe as a seam: the junction of the northern and southern hemispheres; this circle is called the equator. It is a circle of latitude with a value of zero (0 °).

Parallel to the equator, other circles are located above and below it - these are other latitudes of the Earth. Each latitude has a numerical value, and the scale of these values ​​is measured not in kilometers, but in degrees north and south from the equator to the poles. The poles are: North + 90 °, and South -90 °.

Latitudes located above the equator are called north latitude, and below the equator - south latitude. Lines of latitude are sometimes called parallels because they run parallel to the Equator. If parallels are measured in kilometers, then the lengths of different parallels will be different - they increase as they approach the equator and decrease towards the poles.

All points of one parallel have the same latitude, but different longitudes (the description of longitude is just below). The distance between two parallels, which differ by 1 °, is 111.11 km. On the globe, as well as on many maps, the distance (interval) from latitude to another latitude is usually 15 ° (this is about 1,666 km). In Figure 1, the interval is 10 ° (this is approximately 1,111 km). The Equator is the longest parallel, its length is 40,075.7 km.

However, in order to pinpoint any location on the globe, it is not enough to know its position relative to the north and south, you also need to know the meaning relative to the west and east. For this, lines of longitude are used. Since there is no west or east poles, it was decided that the line of zero longitude passes through the Greenwich laboratory, located in England on the east outskirts of London.

Lines of longitude are called meridians (Figure 2). They all run perpendicular to the equator and intersect with each other at two points at the North and South Poles. To the east of the prime meridian there is an area of ​​eastern longitudes, to the west - western longitudes. Eastern longitudes are considered to be positive, western longitudes - negative.

The meridian passing through Greenwich is called the prime meridian (or sometimes the Greenwich meridian). Longitude is measured in degrees. The meeting of the eastern and western lines of longitude occurs at Pacific on the date line. All lines of longitude intersect at the poles, and there is no longitude at these locations. One degree of longitude does not mean any fixed distance: at the equator, a difference in longitude of 1 degree is equal to 111.11 km, and closer to the poles it tends to zero.

The lengths of all meridians from pole to pole are equal - 20,003.93 km. All points of the same meridian have the same longitude, but different latitudes. On the globe, as well as on many maps, the distance (interval) from longitude to another longitude is usually 15 °.

Almost all of you have paid attention to the "mysterious lines" on maps and globes representing latitude (parallels) and longitude (meridians)... They form a gridded coordinate system by which any place on Earth can be pinpointed - and there is nothing mysterious or complicated about it. Parallels and meridians are imaginary lines on the surface of the Earth, and latitude and longitude are their coordinates, which determine the position of points on the surface of the Earth. Any point on Earth is the intersection of a parallel and a meridian with latitude and longitude coordinates. This can be most clearly studied with the help of a globe, where these lines are indicated.
But first, everything is in order. Two places on Earth are determined by its rotation around its own axis - this is North and South Poles... On globes, the pivot is the axis. The North Pole is located in the Arctic Ocean, which is covered with sea ice, and researchers in the olden days reached this pole on a sleigh with dogs (it is officially believed that the North Pole was discovered in 1909 by American Robert Perry). However, since the ice moves slowly, the North Pole is not an actual object, but rather a mathematical object. The South Pole, on the other side of the planet, has a permanent physical location on the continent of Antarctica, which was also discovered by land explorers (Norwegian expedition led by Roald Amundsen in 1911).

Halfway between the poles, at the "waist" of the Earth, there is a large circle line, which is represented on the globe as a seam: the junction of the northern and southern hemispheres; this circle line is called - equator... The equator is a line of latitude with a zero value (0 °). Parallel to the equator, above and below it, other lines of the circle are located - these are other latitudes of the Earth. Each latitude has a numerical value, and the scale of these values ​​is measured not in kilometers, but in degrees north and south from the equator to the poles. The poles are: North + 90 °, and South -90 °. Latitudes located above the equator are called northern latitudes, and below the equator - southern latitudes... Lines with degrees of latitude are called parallels, since they run parallel to the Equator and are parallel to each other. If parallels are measured in kilometers, then the lengths of different parallels will be different - they increase as they approach the equator and decrease towards the poles. All points of one parallel have the same latitude, but different longitudes (the description of longitude is just below). The distance between two parallels, which differ by 1 °, is 111.11 km. On the globe, as well as on many maps, the distance (interval) from latitude to another latitude is usually 15 ° (this is about 1,666 km). In Figure 1, the interval is 10 ° (this is approximately 1,111 km). The Equator is the longest parallel, its length is 40,075.7 km.