Presentation on geography axial rotation of the earth. Presentation on "the rotation of the earth". "If the Earth did not rotate ..."

1 Lecture 4. Axial (daily) rotation of the Earth Daily rotation Earth around the polar axis. Evidence for the rotation of the earth. Geographic implications of the Earth's rotation.

Slide 2

2 The Earth rotates around its axis from west to east (as viewed from the North Pole) counterclockwise. The Earth makes a complete revolution relative to the stars surrounding the solar system in 23 hours 56 minutes 4.0905 seconds. For convenience, it is customary to consider the time of a full turnover of 24 hours. The angular speed of rotation of all points of the Earth is the same: 360 ° / 24 = 15 °.

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3 The linear speed of rotation of points depends on the distance that they must travel during the period of the Earth's daily rotation. Only the exit points of the imaginary axis - the points of the geographic poles - remain motionless on the surface. The points on the equator line have the highest rotation speed - 464 m / s. Consequently, the rotation speed will decrease from the equator to the poles. Linear speed for any latitude is rounded off by the formula: V 1 = V cos φ, where V is the speed at the equator, φ is the latitude of the area: V 1 = 464 * cos 52 ° = 464 * 0.6032 = 279.88 m / s We are not we notice the rotation of the Earth because all objects and the atmosphere rotate uniformly with the surface of the Earth. On the contrary, it seems to us that the heavenly bodies move from east to west, i.e. towards the actual motion of the Earth.

Slide 4: Foucault's Pendulum

4 Foucault's pendulum It is known from physics that the swing plane of a pendulum does not change if the pendulum is not acted upon by any forces other than gravity. In 1851, the French physicist L. Foucault, on the basis of this law, made an experiment proving the rotation of the Earth around its axis. In the tallest building in Paris, the Pantheon, a heavy metal ball with a point was suspended from a thin steel wire. A platform was made under this huge pendulum, on which sand was poured. When the pendulum began to swing slowly, we noticed that the tip leaves a mark on the sand, and as a result of each new swing of the pendulum, the line passing through the swing center deviates at its ends to the right when viewed from above from the previous one. In reality, it is not the pendulum that is deflected - it retains its swing plane, but the position in the space of the entire earth changes along with the room in which the pendulum swings.

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5 The amount of deflection of the pendulum depends on the latitude of the observation site. At the equator, this effect is not at all pronounced, and as the distance from the equator increases, it is more noticeable at the poles. Here, the deviation of the swing lines of the pendulum during each hour is 15 °, and 360 ° per day. The magnitude of the apparent rotation of the swinging plane of the pendulum in one hour can be calculated for any latitude by the formula: α = 15 ° * sin φ where a is the sought value, φ is the latitude of the area, and 15 ° is the angular value of the Earth's rotation in 1 hour. The swing line of the pendulum deviates to the right in the northern hemisphere, and to the left in the southern hemisphere. This means that the rotation of the Earth around its axis occurs from west to east. Positions of the swinging plane of the pendulum during the daily rotation of the Earth

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Slide 7: Deflection of falling bodies

7 Deviation of falling bodies If you throw a body from a high tower, then it does not fall vertically, but deviates somewhat to the east. This is because the top of the tower is farther from the center of the Earth than its base, and therefore follows a longer circle as the Earth rotates. The falling body at the top of the tower had a greater horizontal speed than at its base, and therefore reached the Earth's surface at a point lying slightly east of the plumb line (Fig.). In a mine 158.5 m deep, the body deflects by 27.5 mm when it falls. The deflection effect of the falling body, in contrast to previous experience, is best expressed at the equator and is completely absent at the poles.

Slide 8: Flattening of the Earth

8 Flattening of the Earth Flattening of the Earth indicates its rotation around its axis. It is known that rotation generates centrifugal force, which, under the conditions of the Earth, which has a spherical shape, manifests itself unequally in different places. Linear speed is not the same at different latitudes. At the equator, each point runs 464 m / s, at the latitude of Moscow - only 260 m / s, and at the pole, this value is practically zero. Centrifugal force is proportional to the square of the speed and is greatest at the equator, absent at the poles. This force gave the Earth the shape of an ellipsoid of revolution, the surface of which is closest to the center of the Earth at the poles and farthest at the equator, like the surface of rings that contract during rotation (Fig.) Thus, the centrifugal force and distance from the center of the Earth make the gravity unequal in different places. At the equator, every body weighs less than at the pole, by 1/200 part.

Slide 9: GEOGRAPHIC VALUE OF DAILY ROTATION OF THE EARTH

9 GEOGRAPHICAL VALUE OF DAILY ROTATION OF THE EARTH BALLOON Together with the spherical figure of the Earth's rotation in the field of solar radiation, the zonality of nature is determined. 2. Axial rotation causes the change of day and night. As a result of the change of day and night, a diurnal regime of processes in GO arises. If there was no daily rotation of the Earth, then one side of it would be continuously heated, and the other would be cooled, and this would be reflected in all natural processes of the earth's surface.

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Slide 10: 3. When the Earth rotates around its axis, two points remain stationary - the poles - this makes it possible to build a coordinate grid on the ball, i.e. meridians, parallels, equator

10 3. When the Earth rotates around its axis, two points remain motionless - the poles - this makes it possible to construct a coordinate grid on the ball, ie. meridians, parallels, equator. Meridian (Latin - "noon") is a line connecting the poles. There are no objective criteria to determine the initial meridian, so it was chosen conditionally - the meridian passing through the Greenwich Observatory, it is called the initial or Greenwich. Longitudes are counted from it. Longitude is the distance in degrees from the prime meridian to the meridian passing through an object. For convenience, longitudes are counted in both directions from Greenwich, from 0 ° to 180 ° to the east - east longitudes, to the west - west.

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Slide 11

11 Equator is the line formed by the intersection of the earth's surface by a plane perpendicular to the axis of rotation of the earth and equidistant from the poles. This is the line of the largest circle on the earth's surface. It divides the Earth into two hemispheres: northern and southern. If you mentally cross the Earth with planes parallel to the equatorial plane, then lines will appear on the surface with a west-east direction, which is called parallels. The remoteness of the parallels, and, consequently, of any point from the equator in degrees of the meridian, is called latitude. Latitude is measured in the range from 0 ° to 90 ° and is north and south. The length of the parallels decreases from the equator to the stripes; accordingly, the linear speed of rotation of all parallels also decreases. The linear speed of rotation of all points on one parallel is the same.

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Slide 12: Geographic coordinates

12 Geographic coordinates Geographic latitude  is the angle between the normal to the surface of the ellipsoid (or between the plumb line - perpendicular to the surface of the geoid) and the plane of the equator. The values ​​of latitudes, which are measured from the equator to the north pole, are taken into account with the plus sign, north, and to the south - with the minus sign, south. The latitude of the equator is 0 °, the latitude of the north pole is + 90 °, and the latitude of the south pole is - 90 . Geographic longitude  is the dihedral angle between the plane of the geographic meridian of a point and the plane of the prime meridian. Longitude is measured from the Greenwich meridian to the east from 0 to 360 °, or to the east from 0 to 180 °, and to the west from 0 to 180 °, indicating "east longitude", "west longitude". Longitude and latitude can also be defined respectively by the length of the arc of the meridian and the parallel on the surface of the ellipsoid.

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Slide 13: 4. The rotation of the Earth causes the action of the deflecting force of the Earth's rotation

13 4. The Earth's rotation causes the action of the deflecting force of the Earth's rotation The deflecting force of the Earth's rotation, or Coriolis force, is manifested in the fact that all bodies moving on the earth's surface, or parallel to it, deviate from their direction in the northern hemisphere to the right, in the southern hemisphere - to the left. When moving, all bodies tend to maintain a rectilinear direction. But their movement takes place in a rotating sphere. Therefore, they seem to deviate from the original direction. In fact, it is not the bodies that are deflected, but the surface itself, along which or over which these bodies move. Gustave Gaspard Coriolis (Gaspard-Gustave de Coriolis) (05/21/1792 - 09/19/1843)

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Slide 14

14 A rocket was launched from point A towards the North Pole. At the time of launch, its direction coincided with the direction of the meridian. After some time, point A, as a result of the rotation of the Earth, moves to point B. The direction of the meridian deviated to the left. A moving body according to the law of inertia seeks to maintain its direction and speed in world space. The rocket maintains its original direction, and it seems to the observer that the rocket has deviated to the right. It is easy to see that this deflecting force is fictitious, that it is not a moving body that is deflected, but that the surface of the Earth changes its spatial position. The deviation will be greatest at the poles, and at the equator it will be 0 °, because the meridians there are parallel to each other and their direction in space does not change. Deviation in the northern hemisphere occurs to the right, in the southern - to the left. The Coriolis force affects all moving objects, regardless of the direction of movement. The magnitude of the deflecting action of the Earth's rotation on a body weighing 1 kg is expressed by the formula: F = 2ω * ν * sin φ where ω is the angular velocity of the Earth, ν is the speed of the body, α is the latitude.

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Slide 15: 5. The rotation of the Earth around the axis gives the main unit of time measurement - day

15 5. The revolution of the Earth around the axis gives the main unit of time measurement - day. Solar day - the time interval between two successive passages of the center of the Sun through the meridian of the observation point. True solar time is the period of time between two successive upper climaxes of the center of the Sun through the meridian of the observation point. The duration of true solar days varies throughout the year primarily due to the uneven motion of the Earth in an elliptical orbit. Hence, they are also inconvenient for measuring time. Average solar time is the time interval between two successive upper culminations of the center of the average Sun through the meridian of the observation point - a fictitious point uniformly moving along the celestial equator with the average speed of movement of the true Sun along the ecliptic. Average solar days are equal to 24 hours. For practical purposes, average solar days are used. They are longer than stellar ones, because the Earth rotates around its axis in the same direction in which it orbits the Sun with an angular velocity of about 1 ° per day. Because of this, the Sun shifts against the background of the stars, and the Earth still needs to turn about 1 ° in order for the Sun to "come" to the same meridian. Thus, for a solar day, the Earth makes a revolution by about 361 °.

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Slide 16

16 sidereal day - the time interval between two successive upper climaxes of a star through the meridian of the observation point (the time of a complete revolution of the Earth around its axis). The time between two passes of a star through the meridian of a given place, a sidereal day is 23 hours 56 minutes 4 seconds. This is the actual time of the Earth's daily circulation. (since the Earth moves around the Sun and around the axis in one direction, then the solar day is longer than the actual time of a complete revolution). Sidereal days contain 86400 s = 24 hours. Stellar day. Starting position. A sidereal day is slightly shorter than a sunny day. When the sidereal day ends, the Earth must turn a little more to "catch up" with the Sun.

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Slide 17

17 in Everyday life It is also inconvenient to use the average solar time, since it has its own time on each meridian - local time. The presence of their local time at different points lying on different meridians led to many inconveniences. Therefore, at the International Astronomical Congress in 1884, the standard time count was adopted. For this, the entire surface of the globe was divided into 24 time zones, 15 ° each. The local time of the average meridian of each belt is taken for standard time. The zero (aka 24th) belt is the one in the middle of which the zero (Greenwich) meridian passes. Its time is accepted as universal time. The belts are counted from west to east. In two neighboring zones, zone time differs by exactly 1 hour. For convenience, the boundaries of time zones on land are drawn not strictly along the meridians, but along natural boundaries (rivers, mountains) or state and administrative boundaries. To convert local time to universal time and back, you need to know the angular distance of the place from the prime meridian, i.e. longitude of the place. The universal time is used in astronomy, in practical life it is actually not used. To convert local time into zone time and vice versa, the following formula is used: Тп = Тм + n - λ, where Тп - zone time, Тm - local time, n - zone number, λ - longitude.

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Slide 18

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Slide 19

19 After the October Revolution, on February 8, 1918, the zonal division was introduced by a decree of the Council of People's Commissars. By a government decree of June 16, 1930, the hands of all clocks in the territory Soviet Union were moved forward one hour. Formed daylight saving time, the introduction of which made it possible to save electricity. The validity period of the daylight saving time was set "until canceled" (existed until 1981). By a resolution of the Council of Ministers on April 1, 1981, the hands of the clock were moved forward one hour more. Thus, daylight saving time was already two hours ahead of the standard time. For ten years, for the winter period, the clock hands were set back one hour compared to summer time, and in the summer they returned to their place. Daylight saving time was canceled in March 1991. The lead by two hours ahead was abolished. We switched to the summer-winter time frame. In winter, standard time was used, and in summer, the clocks were set forward 1 hour. In Belarus, the decree of the Council of Ministers No. 1229 of September 15, 2011 approved the calculation of time in accordance with the international system time zones in standard time plus one hour without setting the hands to seasonal time.

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Slide 20: 6. Date line

20 6. Date line Magellan's trip around the world and the loss of one day. The 180 ° meridian is taken as the international date line. This is a conditional line on the surface of the globe, on either side of which hours and minutes coincide, and calendar dates differ by one day. For example, in New Year at 0:00 a.m. to the west of this line on January 1 of the new year, and to the east - on December 31 of the old year. When crossing the date border from west to east in the invoice calendar days return one day ago, and from east to west - one day is skipped in the date count. For the convenience of calculating, the international agreement was considered to be the beginning of a new day in the 12th time zone, i.e. meridian 180 °. This is the date line.

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Slide 22: 8. The change of day and night creates a daily rhythm in living and inanimate nature

22 8. The change of day and night creates a daily rhythm in living and inanimate nature


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Slide 23: 9. Ebb and flow

23 9. Ebb and flow The ebb and flow of the earth is a consequence of the Earth's rotation. The moon, as the celestial body closest to the Earth, has a great force of attraction. This force causes deformation of the Earth's surface, especially its water shell. At the point closest to the Moon, as well as at the opposite point on the Earth, a tidal ledge always forms. The tide on the side of the Earth facing the Moon is explained by the fact that here the force of gravity is greatest. The tide on the opposite side of the Earth is explained by the fact that the centrifugal force arising from the rotation of the Earth and the Moon around their common center of gravity, located inside the Earth, exceeds the gravity of the Moon. The tides are observed on the Earth - Moon line, and the ebbs - on the perpendicular line.

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Slide 24

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The last slide of the presentation: Lecture 4. Axial (diurnal) rotation of the Earth

25 Low tide (Brittany, France)

Remark 1

  1. Hot Light Belt;

Definition 1

Illumination Belt

Hot Belt of Illumination

Moderate light belts

Cold belts of illumination

Definition 2

Polar day

Definition 3

polar night

1. Light belts of the Earth.

Tasks according to Fig. 1.

1) Sign the names of the poles, tropics, polar circles, and sanctification belts of the Earth.

2) Indicate the day of the year and the peculiarities of the position of the Sun at the poles, tropics and polar circles, the seasons that occur in different parts of the Earth's surface.

3) Fill in the missing words.

Summer begins in the northern hemisphere, winter in the southern. The sun is at its zenith above the line northern tropic, does not go beyond the horizon above the line arctic circle... In the Northern Hemisphere, the length of the day is longer than the length of the night.

Summer solstice day.

2. Rotation of the Earth around its axis.

Tasks according to Fig. 2.

1) Indicate the direction of rotation of the Earth around its axis.

2) Designate the areas of the Earth where you can observe: a) the sunrise; b) evening twilight; c) day and night.

3) Fill in the missing words.

The earth makes a complete revolution on its axis in 24 hours. If in your locality it is day now, then in 12 hours it will be night. In 24 hours, the Earth will rotate 360 ​​degrees, and in 1 hour - 15 degrees.

School of the geographer-pathfinder.

While working with the Earth-Moon-Sun (Tellurium) model, compose and record a story about one of the four special positions of the Earth in the circumsolar orbit.

  1. The date corresponding to the given position of the Earth. In this position, the Earth is in circumsolar orbit on June 22.
  2. The seasons that end spring-autumn and begin summer-winter on this day according to the astronomical calendar. On this day in the Northern Hemisphere, spring ends and summer begins. And in the Southern Hemisphere, autumn ends and winter begins.
  3. The sides of the horizon from where the sun rises and where the sun sets on that day. The sun on this day rises in the west and sets in the east.
  4. Sunrise and sunset times on this day. The sun rises early on this day and sets late.

The natural change in the position of the Earth in relation to the Sun during its orbital motion while maintaining a certain inclination of the axis of rotation determines the position on the Earth of the lines of the tropics and polar circles, limiting the belts of illumination (astronomical heat belts). They stand out depending on the midday height of the Sun and the duration of illumination (from the length of the day).
Between the tropics (north - the Tropic of Cancer and the south - the Tropic of Capricorn) lies a hot astronomical belt, within which the Sun twice a year stands at noon at its zenith. At the equator, these moments are separated by equal time intervals of 6 months (March 21 and September 23). In the tropics, the Sun is at its zenith only once a year - on the days of the solstices (in the northern tropics - June 22, in the southern - December 23). In the belts located between the tropics and the polar circles, in moderate astronomical belts, The sun does not appear at its zenith, but within 24 hours there must be a change of day and night, and their duration depends on the season and latitude. In the polar circles, the Sun does not rise above the horizon higher than 47 °, but in summer it may not hide behind the horizon for a whole day. In winter, the sun is not shown at all throughout the day. North of the Arctic Circle and south of the South Arctic Circle are cold astronomical belts... They differ in that at a low position above the horizon (less than 47 °) the Sun does not hide for up to six months (at the poles) and the same period of time does not appear (Tables 2, 3).

The higher the Sun is above the horizon, the more solar heat is received by the surface on which its rays fall. Therefore, the belts between the tropics are hot, the belts between the polar circles and the poles are cold. The intermediate (located between the tropics and the polar circles) belts in terms of the amount of heat received from the Sun are moderate. The lines of the tropics and polar circles can be taken as the boundaries of the thermal zones only conditionally, since in reality the temperature is determined by a number of conditions that depend primarily on the nature of the surface. But these lines, of course, are the boundaries of belts with different durations of illumination by their sunbeams.
The location of the line of the tropics and polar circles depends on the angle of inclination of the axis of rotation of the planet to its orbit. If the Earth's axis did not have an inclination to the orbit, these lines would not exist at all, and the belts of illumination (astronomical heat belts) would not stand out. This situation exists, for example, on Mercury. On a planet whose axis of rotation is inclined to orbit by 45 °, at latitudes 45 ° N. and y. on the day of the summer solstice in the corresponding hemisphere, the sun's rays fall vertically (as on the earth's tropics), and on the day of the winter solstice, the sun does not appear over the horizon (as on the earth's polar circles). There will be no moderate astronomical belt on such a planet at all.
A change in the inclination of the planet's rotation axis to its orbit causes the expansion or contraction of astronomical heat belts (light belts).
The result of the rotation of the Earth around its axis and the resulting change of day and night is circadian rhythm processes in the geographic shell of the Earth. During the day, the amount of solar energy received by the surface naturally changes, temperature, humidity, atmospheric pressure, and air movement change. Organisms are sensitive to these changes, which in turn affect their environment. The daily rhythm of the processes manifests itself against the background of their annual rhythm, conditioned by the movement of the Earth around the axis, by the change of seasons and expressed in the regular change of phenomena in nature.

It decreases from the equator to the poles, which is the result of the spherical shape of the planet. The height of the noon Sun near the equator and at the equator will be the highest, and at the Poles of the planet - the smallest. This leads to the fact that each unit of the area of ​​solar heat and light receives less and less.

Remark 1

As a result of such an uneven distribution of solar heat and light, the Earth's surface was divided into five belts of illumination, the boundaries of which are the tropics and polar circles:

  1. Hot Light Belt;
  2. Two moderate zones of illumination;
  3. Two cold zones of illumination.

The reason for the formation of these belts is the inclination of the axis of rotation of the planet to the orbital plane, as well as the movement of the Earth around the Sun.

Definition 1

Illumination Belt- This is a part of the Earth's surface, bounded by the tropics and polar circles with their own lighting conditions. Illumination is the flux of sunlight falling on a unit of surface.

The belts differ from each other in the height of the noon Sun above the horizon, in the length of the day and in thermal conditions. Once a year ($ 22 in June and $ 22 in December), the sun's rays fall steeply in the North and South Tropics. The polar day and the polar night also happen once a year ($ 22 in December and $ 22 in June), which is typical for the Arctic and Southern Polar Circle. Illumination belts are characterized by different air temperatures and different natural conditions.

Hot Belt of Illumination

This belt covers $ 2/5 $ or about $ 40 \% $ of the Earth's surface and is located between the North and South tropics. The sun in this belt is always high above the horizon, so the surface warms up very well. There is no difference between summer and winter temperatures, and there are no thermal seasons. The average annual air temperature is $ + 25 $ degrees. The length of daylight hours and the length of the night are approximately the same and amount to $ 12 per hour. There is no twilight. The sun is twice a year at its zenith - in the Northern and Southern tropics. The boundaries of the hot zone coincide with the boundaries of the distribution of palm trees on land and corals in the ocean. The territory of this belt is called "hot", because it receives the largest amount of heat throughout the year.

Moderate light belts

There are two of these light belts on Earth - one in the Northern Hemisphere, the other in the Southern Hemisphere. Both of them adjoin the hot zone and are located between the polar circles and the tropics. In contrast to the hot belt of illumination, the sun's rays here fall on the Earth's surface already at a certain tilt. To the north, this tilt will increase, which means that the Earth's surface is warming up less and temperatures will be lower. In temperate zones of illumination, the Sun is never at its zenith. The seasons are clearly defined here. As we approach the Arctic Circle, winter becomes long and cold; as we approach the tropic, summer becomes warmer and longer. From the side of the poles, the moderate belts of illumination are limited by the $ + 10 $ degrees isotherm. This is the border of the spread of forests. More than half of the earth's surface is in the moderate zones of illumination. In summer, near the polar circles, there is such a phenomenon as white nights, which can be observed in northern cities located at the latitude of St. Petersburg. In summer, the length of the day, depending on the geographic latitude, is much longer than the length of the night. In winter, the length of the night increases.

Cold belts of illumination

One cold belt of illumination is located in the Northern Hemisphere, the other in the Southern Hemisphere. They occupy only $ 8 \% $ of the territory and are located inside the polar circles. The conditions for the distribution of solar heat and light in these lighting belts are the most interesting. The sun in winter is not shown at all because of the horizon, the polar night sets in. In the summer period, the Sun does not have time to hide behind the horizon, so a polar day is observed. Towards the poles, the duration of polar days and nights increases and reaches six months. Winters are cold and harsh, while summers are cool and short. Even in summer, the angle of incidence of the sun's rays is very small, so the surface heats up weakly. During the polar night, the influx of heat is completely absent and strong cooling occurs. The North and South Poles are the kingdoms of eternal ice.

Definition 2

Polar day- this is the period during which the Sun at high latitudes does not descend beyond the horizon around the clock.

Closer to the pole, the duration of the polar day increases and reaches $ 189 $ days at the North Pole, at the South Pole, due to the unequal speed of the Earth's motion, the duration is somewhat shorter. On the parallel of $ 68 $ degrees - this is the polar circle - a day lasts about $ 40 $ a day.

Definition 3

polar night- This is the period during which the Sun does not rise above the horizon at high latitudes.

This phenomenon is opposite to the polar day and is also observed in the Northern and Southern Hemispheres. The polar night is in fact always shorter than the polar day. Dividing the planet into such large light belts does not satisfy practical needs. Determining the height of the Sun and the length of daylight hours is quite simple. Let's look at an example.

In St. Petersburg, for example, whose latitude is $ 60 degrees at noon, $ 21 in March and $ 23 in September, the Sun will be at an altitude of $ 90-60 = $ 30 degrees. When the Sun is in the tropics, its height at noon will increase by $ 23 $ degrees $ 27 $ minutes. Then the length of the day in St. Petersburg $ 21 $ in June will be $ 90-60 + 23.27 = $ 53 degrees $ 27 $ minutes, which is $ 18.5 hours. In winter, the Sun moves to the Southern Hemisphere, its height naturally decreases and reaches its minimum mark on the days of the solstices. In this case, it decreases by $ 23.27 degrees. For St. Petersburg, $ 22 December, the Sun will be at an altitude of $ 90-60-23.27 = $ 6.33 degrees. The duration of daylight hours at such an altitude of the Sun will be only $ 5.5 $ hours.

Of all the zones of illumination that exist on Earth, the most comfortable conditions for humans are noted in temperate zones closer to hot ones. Cold belts are of little use for life. There is an excess of energy in hot zones.

Illumination of the Earth's surface and health

Daylight plays a very important role in people's lives. It not only provides visual perception, but also affects the basic life processes, regulating metabolism and resistance to adverse environmental factors. Nature established the rhythm of life by the alternation of day and night. Natural light, as shown by numerous experiments, is an element of time in a person's internal clock. The atmosphere created by lighting affects people's mood and their performance.

Seasons... The Earth makes a complete revolution around the Sun in 365 days and 6 hours. For convenience, it is generally accepted that there are 365 days in a year. And every four years, when the extra 24 hours "accumulate", a leap year begins, in which not 365, but 366 days (29 - in February).

In September, when you come back to school after the summer break, autumn comes. The days are getting shorter and the nights are longer and cooler. In a month or two, the leaves will fall from the trees, fly away migratory birds, the first snowflakes will whirl in the air. In December, when the snow covers the ground with a white shroud, winter will come. The shortest days of the year will come. Sunrise at this time is late and early sunset.

In March, when spring comes, the days lengthen, the sun shines brighter, the air becomes warmer, and streams begin to murmur all around. Nature comes to life again, and soon the long-awaited summer begins.

So it was and will always be from year to year. Have you ever wondered why the seasons change?

Geographic Implications of Earth Movement... You already know that the Earth has two main motions: it rotates on its axis and revolves in an orbit around the Sun. In this case, the earth's axis is inclined to the orbital plane by 66.5 °. The movement of the Earth around the Sun and the tilt of the Earth's axis determine the change of seasons and the length of the day and night on our planet.

Twice a year - in spring and autumn - there come days when on the whole Earth the length of the day is equal to the longitude of the night - 12 hours. The vernal equinox occurs on March 21-22, and the autumn equinox is on September 22-23. At the equator, day is always equal to night.

The longest day and shortest night on Earth occurs in the Northern Hemisphere on June 22, and in the Southern Hemisphere on December 22. These are the days of the summer solstice.

After June 22, due to the movement of the Earth in orbit, in the Northern Hemisphere, the height of the Sun above the horizon gradually decreases, the days become shorter and the nights are longer. And in the Southern Hemisphere, the Sun rises above the horizon and daylight hours increase. The Southern Hemisphere receives more and more solar heat, and the Northern - less and less.

The shortest day in the Northern Hemisphere is December 22, and in the Southern Hemisphere - June 22. This is the day of the winter solstice.

At the equator, the angle of incidence of sunlight on the earth's surface and the length of the day change little, so it is almost impossible to notice the change of seasons there.

On some features of the movement of our planet... There are two parallels on Earth, on which the Sun at noon on the summer and winter solstices is at its zenith, that is, it stands directly above the observer's head. Such parallels are called the tropics. In the Northern Tropics (23.5 ° N), the sun is at its zenith on June 22, in the Southern Tropic (23.5 ° S) - on December 22.

Parallels located at 66.5 ° north and south latitude are called polar circles. They are considered the boundaries of territories where polar days and polar nights are observed. A polar day is a period when the Sun does not sink below the horizon. The closer from the Arctic circle to the pole, the longer the polar day. At the latitude of the Arctic Circle, it lasts only one day, and at the Pole - 189 days. In the Northern Hemisphere at the latitude of the Arctic Circle, the polar day begins on June 22 - the day of the summer solstice, and in the South - on December 22. The duration of the polar night ranges from one day (at the latitude of the polar circles) to 176 (at the poles). All this time the Sun does not appear above the horizon. In the Northern Hemisphere, this natural phenomenon begins on December 22, and in the Southern Hemisphere - on June 22.

1. The annual motion of the Earth around the Sun. 2. Our planet is in this position on the days of the summer and winter solstices. 3. Light belts of the Earth.

It is impossible not to note that wonderful period at the beginning of summer, when the evening dawn converges with the morning and twilight lasts all night - the white nights. They are observed in both hemispheres at latitudes exceeding 60 °, when the Sun at midnight drops below the horizon by no more than 7 °. In St. Petersburg (about 60 ° N), white nights continue from June 11 to July 2, and in Arkhangelsk (64 ° N) - from May 13 to July 30.

Illumination belts... The consequence of the annual movement of the Earth and its daily rotation is the uneven distribution of sunlight and heat over the earth's surface. Therefore, there are belts of illumination on Earth.

    Between the North and South tropics, on either side of the equator, lies a tropical illumination belt. It occupies 40% of the earth's surface, which accounts for the largest amount of sunlight. Between the tropics and the polar circles in the southern and northern hemispheres, there are temperate zones of illumination, which receive less sunlight than the tropical zone. From the Arctic Circle to the Pole, there are polar belts in each hemisphere. This part of the earth's surface receives the least amount of sunlight. Unlike other belts of illumination, only here there are polar days and nights.

    Questions and tasks

    1. Explain how the seasons change on Earth. What are the seasons in your area?
    2. Determine from the geographical map in which light zones the territory of our country is located.
    3. Write out from the textbook all the consequences of the rotation of the Earth around its axis.

Lesson topic: §9 "Axial rotation of the Earth" (lesson 2.4 in the section "Earth in the Universe")

Basic tutorial: V.P.Dronov, L.E.Savelieva, M. Drofa, 2012 Geography. Geography.

Target: to form an idea of ​​the rotation of the planet Earth around its axis and the geographical consequences of the rotation of the Earth around its axis.

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"Presentation for the lesson on the topic" Axial rotation of the Earth ""

Did you solve the tests correctly?

  • Option 1 1) c) Earth
  • 2) b) 8
  • 3) b) Saturn
  • 4) b) gas balls
  • 5) b) Sun
  • 6) b) constellation
  • Option 2 1c) Infinity
  • 2) b) Mercury
  • 3) b) star
  • 4) a) Saturn
  • 5) c) Mercury, Venus, Earth, Mars,
  • Jupiter, Saturn, Uranus, Neptune.
  • 6) b) NO.



Lesson topic: Axial rotation of the Earth.


Lesson plan

1. Rotation of the Earth around its axis.

2. Geographic consequences of the Earth's rotation.


Axial movement of the Earth

Day (24 hours) - a complete revolution of the Earth around its axis.


Geographical implications :

1. Because of high speed rotation (30 km / sec.) around its axis, the Earth is flattened at the poles and has the shape geoid.

2. Due to the rotation of the Earth, all moving bodies are deflected in North hemispheres to the right and in South- left .


equator

Northern pole

Yuzhny pole

The shape and size of the Earth

Earth axis- an imaginary line around which the daily rotation of the earth occurs, is inclined to the plane at an angle of 66.5 °.

Due to the rotation of the Earth around its axis, it is flattened at the poles and has the shape ellipse (geoid)

North and South Poles- points of intersection of the axis of rotation with the earth's surface.

The longest circumference of the Earth - equator(40,076 km)

Vertical (polar) radius of the Earth 6357 km

The horizontal (equatorial) radius of the Earth is 6378 km

Diagonal radius 6375 km



3. Because of axial the rotation of the earth occurs


If you look from the side of the North Pole, then the rotation of the Earth around the axis occurs:

A. from north to south

B. from south to north

V. from west to east

G. from east to west


If you look from the side of the North Pole, then the rotation of the Earth around the axis occurs ...

V. from west to east


A. change of day and night

B. changing seasons

B. season of the year


The rotation of the Earth around its axis determines:

A. change of day and night


Thank you for the lesson

young people


Goals:

  • Form an idea of ​​the reasons for the change of seasons of the year.
  • Explain the features of uneven heating of the earth's surface.

Obor hoping:

  • tellurium;
  • globes (for each school desk);
  • multimedia projector(slide presentation by sections of the lesson);
  • textbook "Planet Earth" ed. A. Lobzhanidze, Publishing House "Education", 2006;
  • atlas “Planet Earth” (“Sphere” series) p.2-3.

During the classes

I. Organizing time(introductory word of the teacher).

II. Check - a summary of the material learned from past lessons.

Task number 1:"Parade of planets". On the table are cards with the names of the planets and the Sun ("Closed" side).
10 students come to the table, take cards, open them and arrange them in order. Each student recalls one particular feature of “their” planet.

Task number 2: During the first task, one student writes down “Our space address” on the board (Universe - Milky Way - Solar system - Planet Earth, etc.)

Generalization. Evaluation of results.

III. Learning new material.

You know that the Earth is spinning. How? (around its axis). For how much a complete revolution? (in 24 hours).

Imagine that the Earth has stopped and does not rotate around its axis. What are the consequences of the disappearance of rotation? (The countdown will disappear. There will be no change of day and night. On the illuminated side, the temperature will be above 100 degrees, and on the “dark” side, frost will be raging. hurricanes, floods, and maybe earthquakes, the strength of which will be incredible)

Besides rotation around its axis, does the Earth still move in any way? (around the sun)
- How long does it take for the Earth to complete one circle in its orbit? Find the exact answer on page 43 of the tutorial. (365 days, 9 minutes, 9 seconds)
- One extra day is accumulated in 4 years. Such a year is called a leap year.

Consider the position of the Earth to the plane of its rotation around the Sun (picture number 1 on the board)

Showcase using tellurium

1) The rotation of the earth around the sun.

Does the axis change its position? (No)
- Is the angle at which sunlight falls the same for the seasons? (No)

Telluria has specific days marked, one for each season. What months do they fall in? (March, June, September, December)
- These days were not chosen by chance. It is during these days that the Earth occupies a unique position in relation to the Sun.

Demonstration in telluria with stops on marked days.

Now write in your notebook the days marked on the slide. Appendix 1 (Slide No. 4)

22.XII - the day of the winter solstice (longest night and shortest day)
21.III - the day of the vernal equinox (day = night).Annex 1 (Slide number 5)
22.VI - the day of the summer solstice (longest day and shortest night)Appendix 1 (Slide No. 4)

23.IX - the day of the autumnal equinox (day = night) Appendix 1 (Slide No. 5)

Diagram on chalkboard

Take a look at the slide. Is the North Polar Region of the Earth illuminated on June 22? (Yes)
- What is the name of this time? (Polar day)
- And in the other hemisphere, in the south polar region? (Polar night)
- This is what the polar night looks like. Appendix 1 (Slide number 6)
- And so - the polar day. Annex 1 (Slide number 7)

Generalization:

What happens on Earth as a result of the Earth's orbital rotation? (Change of seasons)
- Besides, what else does the Earth's orbital motion affect? (For the duration of the day and night)
- It's November. What special day awaits us in December? (Winter solstice)
- How will the Sun be located above the horizon? (Low)

And then it will start to rise again!

Working with the globe

There are lines on the globe in front of you, which are marked with a dotted line. Name them. (Northern and southern tropics, northern and southern polar circles)
- Are these parallels or meridians? (Parallels)
- Let's write it down in a notebook. Polar circles (66.5 N, 66.5 S) Tropics - parallels, where twice a year the Sun is at its zenith (23.5 N, 23.5 S)Annex 1 ( Slide number 8)
- These lines divide our planet into heat zones. Appendix 1 (Slide number 9)
- How many heat zones can you identify? (5) ... Name them.
- What heat zone do we live in? (In northern temperate)

Conclusion.

The earth rotates not only around its axis and around the sun. She still participates in the galactic movement. Appendix 1 (Slide No. 10)
- In the textbook on page 45, find the time of one revolution of the Earth together with the Solar system around the center of the Galaxy. (220 million years)
- What is the rotation speed? (250 km / s)
- But that is not all! Together with our Galaxy, the Earth participates in intergalactic movement. Appendix 1 (Slide number 11)

Generalization: - So, together with the Earth we rotate? .. (Around the axis, around the Sun, around the center of the Milky Way Galaxy and we participate in intergalactic movement)

D / z: pp. 42-45. Highlight the polar circles and tropics on the c / c.

inconvenient, since it has its own time on each meridian. The presence of their local time at different points lying on different meridians led to many inconveniences. Therefore, at the International Astronomical Congress in 1884, the standard time count was adopted. For this, the entire surface of the globe was divided into 24 time zones, 15 ° each. The local time of the average meridian of each belt is taken for standard time. The zero (aka 24th) belt is the one in the middle of which the zero (Greenwich) meridian passes. Its time is accepted as universal time. The belts are counted from west to east. In two neighboring zones, zone time differs by exactly 1 hour. For convenience, the boundaries of time zones on land are drawn not strictly along the meridians, but along natural boundaries (rivers, mountains) or state and administrative boundaries. To convert local time to universal time and back, you need to know the angular distance of the place from the prime meridian, i.e. longitude of the place. The universal time is used in astronomy, in practical life it is actually not used. To convert local time into zone time and vice versa, the following formula is used: Тп = Тм + n -?, Where Тп - standard time, Тm - local time, n - zone number,? - longitude.

 

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