Zooplankton feeds. What is zooplankton, ecological groups
Working with texts and working with 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.
– Length of meridians.
– What are parallels?
– Why are they called that, what do they look like?
– length of parallels.
Teacher: What did you guys learn about the parallels?
Student response.
Parallels are lines that are conventionally drawn along the surface of the earth parallel to the equator. Let's remember what the equator is? Shown on the map and globe. At each point the parallel is directed east and west. Parallels are circles whose length decreases 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 whose length decreases from the equator to the poles. On a 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 walk all the time in the direction of this shadow. Then you will definitely come to the North Pole, and in reverse side- to Yuzhny.
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 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.
Working with maps and atlases.
Teacher: Find the equator on a physical map and on a globe. On contour map mark the equator. It divides the globe into two hemispheres (Northern and Southern). Parallels are counted from the equator. Parallels 10, 20, ... 80 degrees of the Northern or Southern Hemisphere.
Mark a 10 degree parallel Northern Hemisphere and 20 degrees southern hemisphere.
The parallels are marked in a circle on the map of the hemispheres and on the meridian (zero) on the globe.
Teacher: By agreement between the countries, the prime meridian is considered to be the meridian passing through the Greenwich Observatory in the suburbs of London. Therefore, this meridian is also called Greenwich. On the map it is shown as a thicker line than other meridians.
Mark the prime meridian on the map. It divides the globe into two hemispheres (Western and Eastern). Meridians are marked at the equator.
We complete task 43 page 36.
Teacher: Why are parallels and meridians needed?
Students: For orientation, determine and indicate the location of various geographical objects on the surface of the Earth.
Teacher: Right. The ancient Greek scientist Eratosthenes, who lived in 276 -194. BC e., for the first time proposed to apply to images earth's surface conventional lines – parallels and meridians.
Determination of directions by meridians and parallels.
Teacher: What do we know? What directions do the conditional lines show?
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, 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.
- In which direction is Cairo from St. Petersburg?
- In what direction is Moscow from St. Petersburg?
- In what direction from Moscow is the Red Sea.
Using conditional lines, you can determine not only directions, but also indicate the position of parts of territories and objects. To determine, for example, the northern and southern parts of Australia, you need to place a pointer on the map along a parallel that runs approximately in the middle of the continent. To the north of the pointer there will be a northern part, and to the south there will be a southern part. How do you define the western and eastern parts of Australia.
LATITUDES AND MERIDIANS
Almost everyone is familiar with the "mysterious lines" on maps and globes that represent latitude (parallels) and longitude (meridians). They form a grid system of coordinates by which any place on Earth can be precisely located - and there is nothing mysterious or difficult about it. Latitude and longitude are coordinates that determine the position of points on the Earth's surface.
Two places on Earth are determined by its rotation around its own axis - the North and South Poles. On globes, the axis is the rod. North Pole is located in the middle of the Arctic Ocean, which is covered sea ice, and explorers 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 Peri).
However, since the ice moves slowly, the North Pole is not an actual but a mathematical object. U South Pole, on the other side of the planet, there is a permanent physical location on the continent of Antarctica, which was also discovered by land explorers (the 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, above and below it, there are other circles - 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 have the following values: North +90°, and South -90°.
Latitudes located above the equator are called northern latitude, and below the equator - southern 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 when approaching the equator and decrease towards the poles.
All points of the same parallel have the same latitude, but different longitude (longitude is described below). The distance between two parallels that 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 approximately 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.
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However, in order to accurately determine any place on globe, it is not enough to know its position relative to north and south, you also need to know its value relative to west and east. Lines of longitude are used for this. Since there are neither western nor eastern poles, it was decided that the line of zero longitude passes through the Greenwich Laboratory, located in England on the eastern outskirts of London.
Lines of longitude are called meridians (Figure No. 2). They all run perpendicular to the equator and intersect 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 are considered negative.
The meridian passing through Greenwich is called the prime meridian (or sometimes the Greenwich meridian). Longitude is measured in degrees. The meeting of eastern and western lines of longitude occurs at Pacific Ocean on the date line. All lines of longitude intersect at the poles, and at these places there is no longitude. One degree of longitude does not mean any fixed distance: at the equator, a longitude difference of 1 degree is equal to 111.11 km, and closer to the poles it approaches zero.
The lengths of all meridians from pole to pole are equal - 20,003.93 km. All points on the same meridian have the same longitude, but different latitudes. On a globe, as well as on many maps, the distance (interval) from a longitude to another longitude is usually 15°.
If our planet is “cut” through the axis of rotation and perpendicular to it by many planes, then vertical and horizontal circles - meridians and parallels - will appear on the surface.
The meridians will converge at two points - at the North and South Poles. Parallels, as the name suggests, are parallel to each other. Meridians serve to measure longitude, parallels - latitude.
An action so simple at a superficial glance - “ruling” the Earth - has become greatest discovery in planetary exploration. It made it possible to use coordinates and accurately describe the location of any object. Without parallels and meridians it is impossible to imagine a single map or a single globe. And they were invented... in the 3rd century BC by the Alexandrian scientist Eratosthenes.
Reference. Eratosthenes had encyclopedic knowledge in all areas at that time. He was in charge of the legendary Library of Alexandria, wrote the work “Geography” and became the founder of geography as a science, compiled the first map of the world and covered it with a degree grid of verticals and horizontals - he invented a coordinate system. He also introduced names for lines - parallel and meridian.
Meridian
In geography, a meridian is half a sectional line of the earth's surface drawn through any point on the surface. All imaginary meridians, of which there can be an infinite number, connect at the poles - North and South. The length of each of them is 20,004,276 meters.
Although you can mentally draw as many meridians as you like, for ease of movement and mapping, their number and location have been ordered international treaties. In 1884, at the International Meridian Conference in Washington, it was decided that the prime meridian (zero) would be the one that passes through Greenwich, a county in southeast London.
However, not everyone immediately agreed with this decision. For example, in Russia, even after 1884 until the beginning of the twentieth century, the zero meridian was considered to be its own - Pulkovsky: it “passes” through the Round Hall of the Pulkovo Observatory.
Prime meridian
The prime meridian is the starting point of geographic longitude. He himself, accordingly, has zero longitude. This was the case before the creation of the world's first satellite system Navigation Transit.
With its appearance, the prime meridian had to be shifted slightly - 5.3" relative to Greenwich. This is how the International Reference Meridian appeared, which is used as a reference point for longitude by the International Earth Rotation Service.
Parallel
In geography, parallels are lines of an imaginary section of the surface of the planet by planes that are parallel to the equatorial plane. The parallels depicted on the globe are circles parallel to the equator. They are used to measure geographic latitude.
By analogy with the Greenwich prime meridian, there is also a zero parallel - this is the equator, one of the 5 main parallels, which divides the Earth into hemispheres - southern and northern. Other main parallels are the tropics North and South, the polar circles - North and South.
Equator
The longest parallel is the equator - 40,075,696 m. The rotation speed of our planet at the equator is 465 m/s - this is much greater than the speed of sound in air - 331 m/s.
Southern and Northern tropics
The Tropic of the South, also called the Tropic of Capricorn, is located south of the equator and is the latitude above which the noon sun is at its zenith on the day winter solstice.
The Tropic of the North, also known as the Tropic of Cancer, is located north of the equator and, similar to the Tropic of the South, represents the latitude above which the midday sun is at its zenith on the day summer solstice.
Arctic Circle and Antarctic Circle
The Arctic Circle is the border of the region polar day. To the north of it, in any place at least once a year the sun is visible above the horizon 24 hours a day or not visible for the same amount of time.
The Southern Arctic Circle is similar to the Northern Circle in every way, only it is located in the southern hemisphere.
Degree grid
The intersections of meridians and parallels form a degree grid. Meridians and parallels are spaced at intervals of 10° - 20°; smaller divisions, as in angles, are called minutes and seconds.
Using a degree grid, we determine the exact location of geographical objects - their geographical coordinates, calculating longitude from meridians, and latitude from parallels.
Almost all of you have paid attention to the “mysterious lines” on maps and globes representing latitude (parallels) and longitude (meridians). They form a grid coordinate system by which any place on Earth can be precisely located - 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 that 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 using a globe, where these lines are indicated.
But first things first. Two places on Earth are determined by its rotation around its own axis - these are North and South Poles. On globes, the axis is the rod. The North Pole is located in the Arctic Ocean, which is covered with sea ice, and explorers in the old days reached this pole on sleds with dogs (the North Pole is officially believed to have been discovered in 1909 by the American Robert Perry). However, since the ice moves slowly, the North Pole is not an actual, 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 (a Norwegian expedition led by Roald Amundsen in 1911).
Halfway between the poles at the “waist” of the Earth there is a large line of a circle, 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 value of zero (0°). Parallel to the equator, above and below it, there are other lines of the circle - 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 have the following values: 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 the same parallel have the same latitude, but different longitude (longitude is described below). The distance between two parallels that differ by 1° is 111.11 km. On the globe, as well as on many maps, the distance (interval) from one latitude to another latitude is usually 15° (this is approximately 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.