The reasons for the change of day and night are the constant and cyclical rotation of the Earth around its axis. This process is quite rapid, but we manage to notice it on dark evenings or watching the morning dawn. Thanks to the rays of the Sun, the surface of the planet warms up, and we can see the changing darkness and light.
Rays of the Sun and Light of the Moon
The reasons for the change of day and night is that the Earth rotates around an axis that we can mentally imagine. But it simultaneously rotates relative to the Sun. This happens as it moves in orbit around the star.
The reasons for the change of day and night lie in the movement of the Earth along an axis passing through the poles of the planet. She manages to turn around in 24 hours. But around the Sun there is a slower rotation - every 365 days.
The reason for the change of day and night is the rotation of the planet. It's different on different continents. For example, in St. Petersburg there is a season of white nights, and polar days can last more than a month.
What causes uneven daylight hours?
The length of day and night is not the same everywhere due to the fact that the imaginary axis of the Earth is slightly tilted relative to the Sun. Therefore, the rays fall differently on different hemispheres. Thanks to the redistribution of heat, life exists on the planet.
Having managed to cool down overnight, the planet warms up during the day. Vital metabolic processes take place. We see the Earth in such a familiar form thanks to the unique movement of the planet. On different continents, flora and fauna differ due to the length of the day.
The pole can be in the shadow for six months - this time is called the polar night. Then comes the day at the pole for the next six months. While it is night at the North Pole, it is day at the South Pole, and vice versa.
If there were no usual days?
Due to the fact that the Earth is evenly illuminated by the Sun, life exists on the planet. Let’s imagine that it would stop rotating, and there would always be day on one side, and the other would be forever deprived of light. The hemisphere under the Sun would heat up to a temperature at which all living things would dry out.
The second part of the planet would begin to freeze due to lack of sunlight. So in the present we have an ideal planet for life. The diversity of living things is amazing, and this is only possible due to the rotation of the Earth. The change of both day and night is important, as are the changes in weather due to the arrival of different seasons.
Lesson summary on the surrounding world in accordance with the requirements of the Federal State Educational Standard, grade 2
Subject:"The change of night and day."Target:
- explain the change of day and night with the rotation of the earth around its axis, the sequence of events during the day.
Equipment: Table “Solar System”, 2 drawings
depicting day and night, tellurium, globe, Dunno, tablets -
yesterday, today, tomorrow, 24 hours a day.
1. Organizing children to work:
We continue to study the world around us.
Today we will talk about an amazing phenomenon on our planet that you observe every day. More precisely, at the beginning of the day and at the end of it.
We will observe these phenomena on all planets of the solar system and even on the Moon.
Dunno
Our friend Dunno illustrated this phenomenon in two drawings:
Who guessed what he was drawing?
Today we must find out what happens in our life and nature during the day, and what at night?
We must find out why the change of day and night occurs?
Since during the lesson we will talk about many objects of nature and objects around us, we must REMEMBER very important rules and laws of their life.
!Check of knowledge. Table "Solar System"
What celestial bodies are depicted on it? (sun, planets)
Who knows what the science of celestial or cosmic bodies is called? (astronomy)
What are scientists who study celestial bodies called? (astronomers)
Now I’ll find out if you know what all these bodies and objects are called.
Assignment from Lena and Misha:
Lena and Misha, who are keen on astronomy, sent me an envelope by mail with the task:
- What instrument does Lena use to study the bodies of the solar system? (telescope)
-What bodies are included in the solar system? (the sun, planets, these include stars and the moon)
QUIZ:
GUESS THE HEAVENLY BODY BY ITS DESCRIPTION!
I will read out a description of the celestial body, and you guys will answer by raising your hand.
1. The planets themselves glow and illuminate. They are very large celestial bodies, planets move around them. They are spherical in shape. (stars)
2. This is a star. It glows and illuminates the planets. (Sun)
3. They themselves do not glow, but are illuminated by the sun and another star. They are large and move
Around the stars and the sun. They have the shape of a ball. (planets)
4. The planet is illuminated by the sun. When there is day on one side, night on the other. (Earth)
5. A satellite of the Earth moving around it. (Moon)
TRAIN
Now let's imagine a train. We got on the train and looked out the window.
What did we see?
That all the objects around are moving. In fact, the train is moving. That’s why it seems to us that houses, trees, fields, meadows, etc. are moving. This is an optical illusion.
PTOLEMY
He developed his own system of the world, in the center of which he placed the Earth.
According to Ptolemy, the following move around the motionless spherical Earth: the Moon, the Sun and 5 planets, as well as the sphere of fixed stars.
He, like us sitting on the train, saw the Sun moving (rising in the morning, setting in the evening), the Moon and stars moving.
In fact, the Earth itself moves, together with the Moon, around the Sun.
Objects around our train move in exactly the same way.
COPERNIUS
Nicolaus Copernicus created the correct picture of the existing world around us. He placed the Sun in the center, around which the Earth and other planets move.
Let's remember two celestial bodies:
THE SUN - illuminating our planet during the day
MOON - illuminating our planet at night
How are they similar? (illuminate the Earth)
- What kind of light does the Moon shine? (reflected sunlight)
- What is the Sun? (a star that glows and illuminates the planets)
- What is the Moon? (It is a natural satellite of the Earth)
- Guys, tell me what I will now list for you: Ursa Major, Ursa Minor, Cancer, Cygnus??? (these are constellations)
GLOBE
- What shape does our planet Earth have?
- How does it rotate? (around the Sun)
- How else? (around its axis)
You and I walk on the earth's surface, why don't we fall into outer space?
What force keeps us on the surface?
THIS IS THE FORCE OF EARTH GRAVITY.
ISAAC NEWTON discovered the law of universal gravitation.
The earth attracts us, that’s why we walk, move, and do certain work.
If you don't take off from the ground and fly into space. The force of gravity stops acting and a state of weightlessness arises.
Astronauts experience weightlessness for several hours of flight.
They use special devices while in zero gravity. Light clothing, food in special tubes, all small items on laces.
SOLAR SYSTEM TABLE
Guys, what big body holds our planet close to it? (Sun)
- What force prevents our planet from flying into outer space? (the force of solar gravity)
The rotation of our planet around the Sun leads to the alternation of day and night.
LEARNING NEW MATERIAL:
-What do you know about these periods of the day?
- Our friend Dunno again got confused in the words - today, tomorrow, yesterday.
-What do they mean?
-What is the difference between day and night? -What colors can you use to depict them?
TELLURIUM STORY
Our Earth, like all planets, rotates in outer space.
The Earth rotates not only around the Sun, but also around an imaginary axis.
The rays of the Sun bring us warmth and light.
When the Earth turns to the Sun with the side where we live, it seems to us that
The sun is rising in the sky, rising. The sun's rays illuminate our planet from one side and at this time it is DAY. The Earth continues to rotate further and we see that the Sun passes across the sky and begins to descend, and then disappears below the horizon. It is the Earth that turns away from the sun's rays during its rotation. The sun disappears, it becomes dark, NIGHT sets in. And on the other side of the globe it is day.
It takes 24 hours, i.e. DAYS, for the Earth to make a full revolution around its axis.
And from one dawn to another, 24 hours pass.
ATTACHMENT:
- Show on the table how the Earth rotates around the Sun?
(counterclock-wise)
-What other movement does she make?
(around its axis)
- What is the time of complete rotation around an axis called?
(day)
- What is a day equal to?
(24 hours)
- What does the proverb mean? "DAY AND NIGHT, DAYS AWAY."
(a day includes both day and night.)
- Around what axis does the Earth rotate? Real or imaginary?
- How many revolutions does the Earth make per day?
(one)
- So why do we have a change of day and night on our planet?
Results:
- Guys, what new and interesting things did you learn from our conversation today?
- What is an earthly day? And what kind of time-day is this???
HOMEWORK:
For the inhabitants of the Earth, the constant change of day and night is a common occurrence. All life on the planet is subject to the rhythmic alternation of dark and light times of day. However, this does not happen on all planets. For example, on Venus, which rotates very slowly around its axis, a year lasts less than two Venusian days. Jupiter rotates on its axis in about five Earth hours, and Saturn in ten.
The Earth makes a complete revolution around its axis in 23 hours 56 minutes 4.1 seconds, during which time day gives way to night - the sidereal day passes. The sidereal day is understood as the time of a complete revolution of our planet around its axis relative to the stars, considering them to be infinitely distant.
The alternation of day and night creates favorable conditions for all life on Earth. As you know, the Earth has the shape of a ball, and its axis of rotation is constantly inclined to the orbital plane at an angle of 66°33"22". Because of this, the sun's rays illuminate different parts of the earth's surface differently, therefore the length of day and night is different everywhere. It depends on the geographic latitude and time of year.
Only twice a year - on the days of the spring and autumn equinox (March 20-21 and September 23 - approx.) the length of day and night is the same at all latitudes of the Earth and is equal to 12 hours. The sun at this time is at its zenith above the equator, and the terminator - the line separating light and shadow on the surface of the planet, passes through the poles, coinciding with the direction of the meridians. The sun's rays fall on the equator these days at an angle of 90°, and the Northern and Southern Hemispheres heat up evenly.
On the days of the summer and winter solstice (June 22 and December 22 - note from the site), the planet experiences the longest night and the shortest day. For example, on June 22, the Sun is at its zenith over the Tropic of the North (23°07" N). In the Northern Hemisphere on this day at all latitudes, the day is longer than night. North of the Arctic Circle (66°33" N). ) polar day is established - the Sun does not set below the horizon for days. At the Arctic Circle, the polar day lasts a day, and at the poles it lasts up to six months. The Southern Hemisphere is less illuminated on June 22 than the Northern Hemisphere. Here, at all latitudes, the day is shorter than the night, and in the southern polar region the polar night sets in.
The Earth moves around the Sun, but the tilt of the planet's axis of rotation remains constant. Gradually, the height of the Sun above the horizon in the Northern Hemisphere decreases, the days become shorter and the nights longer. Finally, September 23 arrives - the day of the autumnal equinox, when the length of day and night is equal at all latitudes. From this moment on, the Sun begins to illuminate the Southern Hemisphere more. On December 22, the day of the winter solstice, the hemispheres seem to change places. On this day in the Southern Hemisphere at all latitudes, the day is longer than the night, and there is a polar day beyond the Antarctic Circle. At the same time, polar night reigns in the northern subpolar regions.
White nights occur south and north of the polar circles in both hemispheres. At this time, evening twilight turns into morning, and darkness does not come. Beyond the Arctic Circle, white nights precede the polar day - approx. At different latitudes, white nights differ in duration: for example, in St. Petersburg they last from June 11 to July 2, and in Arkhangelsk - from May 13 to July 30.
The satellite of our planet, the Moon, rotates around its axis at such a speed that when moving around the Earth, it is constantly turned to one side. If the Earth moved around the Sun like the Moon and was constantly turned to it with one side, the natural conditions on the planet would change enormously. One hemisphere of the Earth would be illuminated all year round, while the other would be constantly in shadow. The illuminated hemisphere would heat up to a temperature of more than 100 ° C, which means that all rivers, seas and oceans would evaporate. On the dark side of the planet, the temperature would be below -100 ° C, here all the water would turn into ice. At the border of light and shadow, due to large temperature differences, hurricanes would rage, earthquakes and volcanic eruptions would occur.
Please tell me where the windows of your house face?
Does the sun wake you up in the morning, breaking through the window?
Or does the sun see off the evening with gentle rays, softly reflecting in the windows of your house?
Of course, the picture of sunrise and sunset that we know depends on which side the windows of our house face. If you do not take into account cloudy weather when the sun is simply not visible, then meeting the sun at dawn and seeing it off at sunset occurs regularly twice a day - in the morning and in the evening.
Example: Move your mouse across the image from left to right.
A little complicated?
Then here: Time of day for children +3 to >7
What is the time of day?
A day is a cycle of time during which the sun, rising from the east, passes across the sky and sets in the west, then, when night falls on our half of the earth, the sun makes a revolution from the other part of the planet and rises again from the east.
A day lasts exactly 24 hours. Each hour consists of 60 minutes. Every minute of 60 seconds. Accordingly, a day = 24 hours = 1440 minutes = 86,400 seconds. For convenience, two formats are used to indicate time:
- 12 hour time format- time until noon from 0 hours 00 minutes to 11 hours 59 minutes (a.m.) and afternoon from 12 hours 00 minutes to 11 hours 59 minutes (p.m.). This time format is established in England, Ireland, France, Greece, Turkey, and is also used in Australia, Canada, the USA and the Philippines.
- 24 hour time format- from 0 hours 00 minutes to 23 hours 59 minutes. The most common time format used in Russia and many other countries of the world.
How does the change of day and night occur on earth?
In addition to the rotation of the earth around the sun (calendar year), the globe rotates on its axis. A complete revolution around its axis occurs in 24 hours, which are called days.
At the same time, being on the surface of the Earth, we do not feel the movement of the globe, but can only observe it based on the apparent movement of the sun and stars relative to the Earth.
Conventionally, the time of day is divided into several parts:
- Morning- begins with the dawn of the sky in its eastern part and the sun rising over the horizon.
- Day- the movement of the sun across the sky from east to west.
- Evening- sunset in the western sky and the gradually fading colors of the sunset.
- Night- Night time. At this time, the sun passes on the other side of the globe relative to us.
Since the Earth consists of continents located on both sides of the globe, the time of day in each part of the Earth is different. So, if the night is still lasting in New York, then in London it is already morning, in Moscow it is midday, and in Petropavlovsk-Kamchatsky it is already evening.
Interestingly, until recently it was believed that the movement of the globe around its axis was uniform, however, later scientists calculated the inaccuracies and it turned out that unevenness in rotation was still present. These irregularities are associated with a slight oscillation of the globe during rotation (conventionally, the rocking of the Earth, in terminology - nutation), but these changes are so small (less than 0.001 s) that they are not taken into account in compiling the calendar.
Changing the time of day
Many photographers tried to capture the change of day and night. By taking many pictures in a row from one position, it was possible to trace the smooth movement of the sun across the sky, see the movement of the stars, and get beautiful videos of sunrise and sunset. Features of time-lapse photography are when a camera mounted on a tripod in a stationary position takes a series of photographs at certain intervals over a long period.
If the length of the day is constant, then the duration of the components of the time of day varies depending on the time of year. This is due to the tilt of the earth and the movement around the sun along an elliptical path. So in summer, daylight lasts longer than night, and in winter, on the contrary, the night is longer than the day.
Moreover, in different parts of the globe the length of day and night is different. For example, in the Crimea it gets dark quickly in the summer, the night is dark, and in St. Petersburg June is famous for its “white nights”, the sun sets not far below the horizon and therefore the nights seem bright.
Different times of day look and feel different. This is connected with the biological (internal) clock by which a person is accustomed to living (day - wakefulness, night - sleep) and with the variety of color contrast, as well as with mood. By the morning, strength increases, the day is spent in study, business, work, and in the evening there is fatigue, a gradual withdrawal from work, rest and sleep.
The change in time of day was painted by the artist Nikolai Petrovich Krymov in an educational landscape entitled “Changes in the landscape in tone and color at different times of the day.”
For the landscape, a simple motif was chosen - a house near the forest, a diagonally leading path that gives volume to the picture, a field and the sky, sometimes people passing along the path came into view, which gave the picture life. The landscape was captured 9 times at different times of the day, where the artist clearly showed how the landscape, colors and colors change at dawn in the morning, when the shadow from the sun moves during the day, at sunset in the evening and at night.
The entire plant and living world of nature adapts to the rhythm of the changing time of day. In the morning the plants bloom, in the evening the buds close. The human world also adapts to the changing time of day. The most common work schedule, lesson schedule, work of educational institutions and entertainment centers, and even radio and television programs are compiled depending on the time of day.
November 17, 2016Various ancient peoples, be it the Egyptians, Greeks or Romans, tried to explain all the phenomena occurring around them, and this is how the fabulous explanation of the change of day and night has reached our times. The legends of different nationalities are generally similar.
The change of day and night: a fairy tale explanation
With the words “the sun has risen” or “the sun has set” we begin or end another day in life. Our ancestors endowed sunrises and sunsets with great power. These phenomena had sacred meaning for our ancestors.
And indeed, during sunsets and dawns, various rituals and ceremonies, both church and magical, were performed. From here arose the fairytale explanation of the change of day and night. Every social media user has a photo of a sunset or sunrise. Today, modern people do not understand these phenomena and do not know their sacred meaning.
Ancient Greek myth
The ancient Greeks had a fabulous explanation for the change of day and night. The titan Hyperion had three children: Selene, Eos and Helios. Shining with cold light, Selene was the goddess of the Moon. On her head was a crescent moon. She rides along the night road in a chariot drawn by oxen. Selena drives off this road when her star children fade and the marble columns turn pink.
Eos, the goddess of the dawn, announces the coming of a new day. Following Eos, their brother Helios rushes from the east on a shining golden chariot. The Greeks revered him no less than the powerful and supreme Zeus. Helios' rays penetrated into the farthest and darkest corners through black clouds. Their warm light awakened all living things. Thanks to the rays, trees and fruits grew. Helios is the terror of all criminals. The rays of this god blind them. Even the gods cannot hide from such rays.
Helios knows everything about divine “deeds”. It was he who suggested to Demeter that her daughter Persephone was kidnapped by Hades to his dark kingdom of shadows. But it is midday when Helios reaches the west. By evening, Helios's horses and he himself become tired and blush. God heads to his palace to rest, where the divine retinue rests, and Selene’s chariot sets out on the road... This is the Greek cycle of day and night. Their fairytale explanation is similar to the Slavic myth.
Video on the topic
Slavic vision of day and night
The ancient pagan Slavs had a very complex and confusing idea of the world. The sun and sunlight were different concepts for them. For each season, the Slavs had a separate “sun” - Yarilo, Kupailo, Svetovit and Kolyada. They called the sun itself Khoros. By the way, this word meant “circle”. This is where the word round dance comes from.
Like the Greeks, the Slavic fairytale explanation of the change of day and night is simple - Dazhdbog (the sun - the giving god) rode a golden chariot across the daytime sky, harnessed by fiery winged horses. Morning and evening dawns were considered sisters. Moreover, the morning dawn was the wife of the sun. On the day of the summer solstice, the Slavs celebrated their wedding. Like the Greeks, the Sun is an all-seeing eye that watches over everything and everyone. That’s why criminals operate at night to this day.
Ancient Indian concept of the emergence of a new day
The Indian legend about the change of day and night is distinctive. The fairytale explanation says that there was no night. It appeared thanks to one tragic incident. There lived brother Yama and sister Yami. The brother died, and the lonely sister had no choice but to endlessly mourn her unfortunate brother. To all requests and exhortations to calm down and stop shedding tears, Yami only exclaimed: “But he died today!” The gods saw the truth: for the girl to calm down, night is necessary, only then will a new day come. They created the night. Morning came, Yami forgot about grief. And the Hindus began to say “alternate day and night.”
Conclusion
For many years, our ancestors believed in these myths and legends about the creation of day and night, right up to the Middle Ages. Religion and mystical ideas were replaced by science. Nicolaus Copernicus 500 years ago wrote a book about how our planet rotates around its axis, traveling in orbit around the star Sun. So, according to Copernicus, there was a change of day and night.
The fairytale explanation was destroyed. And the scientist’s book was banned by the Pope because it contradicted the Christian religion. Copernicus became famous as the creator of the heliocentric system. The name of this system comes from the name of the sun god Helios, so, according to Copernicus’ theory, the Sun is located at the center of the Universe. The Polish astronomer died of a stroke on May 24, 1543, he was 73 years old.