It takes approximately 24 hrs to complete on rotation.
Days and nights occur due to rotation of the earth.
The circle that divides the day from night on the globe is called the circle of illumination.
Earth rotates on a tilted axis. Earth’s rotational axis makes an angle of 23.5° with the normal i.e. it makes an angle of 66.5° with the orbital plane. Orbital plane is the plane of earth’s orbit around the Sun.
Why are days always longer than nights at the equator?
If there was no Atmosphere, there would be no refraction and the daytime and nighttime would be near equal at the equator, at least during equinoxes.
But due to atmosphere, the sun’s rays gets refracted (bending of Light). Refraction is particularly stronger during the morning and the evening time when the sun’s rays are slant.
Even though the actual sun is below the horizon, its apparent image would appear above the horizon due to refraction. This makes the days longer than nights at the equator.
Why temperature falls with increasing latitude (as we move from equator towards poles)?
Because of the spherical (Geoid) shape of the earth and the position of the sun.
Because the energy received per unit area decreases from equator to poles.
Because Equator receives direct sunlight while Poles receive slant or oblique rays of the Sun.
Revolution
The second motion of the earth around the sun in its orbit is called revolution. It takes 365¼ days (one year) to revolve around the sun.
Six hours saved every year are added to make one day (24 hours) over a span of four years. This surplus day is added to the month of February. Thus every fourth year, February is of 29 days instead of 28 days. Such a year with 366 days is called a leap year.
Solstice
On 21st June, the northern hemisphere is tilted towards the sun. The rays of the sun fall directly on the Tropic of Cancer. As a result, these areas receive more heat.
The areas near the poles receive less heat as the rays of the sun are slanting.
The north pole is inclined towards the sun and the places beyond the Arctic Circle experience continuous daylight for about six months.
Since a large portion of the northern hemisphere is getting light from the sun, it is summer in the regions north of the equator. The longest day and the shortest night at these places occur on 21st June.
At this time in the southern hemisphere all these conditions are reversed. It is winter season there. The nights are longer than the days. This position of the earth is called the summer solstice.
On 22nd December, the Tropic of Capricorn receives direct rays of the sun as the South Pole tilts towards it. As the sun’s rays fall vertically at the Tropic of Capricorn (23½° s), a larger portion of the southern hemisphere gets light. Therefore, it is summer in the southern hemisphere with longer days and shorter nights. The reverse happens in the northern hemisphere. This position of the earth is called the winter solstice.
Equinox
On 21st March and September 23rd, direct rays of the sun fall on the equator. At this position, neither of the poles is tilted towards the sun; so, the whole earth experiences equal days and equal nights. This is called an equinox.
On 23rd September, it is autumn season [season after summer and before the beginning of winter] in the northern hemisphere and spring season[season after winter and before the beginning of summer] in the southern hemisphere. The opposite is the case on 21st March, when it is spring in the northern hemisphere and autumn in the southern hemisphere.
Thus, you find that there are days and nights and changes in the seasons because of the rotation and revolution of the earth respectively.
Rotation === Days and Nights.
Revolution === Seasons.
Why regions beyond the Arctic Circle receive sunlight all day long in summer?
This is because of the tilt of the earth.
Earth’s axis at the North Pole is tilted towards the sun in summer.
So the whole of Arctic region falls within the ‘zone of illumination’ all day long in summer.
Daylight saving in some temperate regions
Daylight saving time (DST) or summer time is the practice of advancing clocks during summer months by one hour.
In DST, evening time is increased by sacrificing the morning hours.
[Normal days = Start office at 10 AM and close at 5 PM
In DST = Advance clock by one hour (can be more) = Start office at 9 AM and Close at 4 PM]
Typically, users in regions with summer time (Some countries in extreme north and south) adjust clocks forward one hour close to the start of spring and adjust them backward in the autumn to standard time.
Advantage: Putting clocks forward benefits retailing, Sports, and other activities that exploit sunlight after working hours. Reduces evening use of incandescent lighting, which was formerly a primary use of electricity.
Problems: DST clock shifts sometimes complicate timekeeping and can disrupt travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns.
Variations in the length of daytime and night time from season to season are due to
the earth’s rotation on its axis
the earth’s revolution round the sun in an elliptical manner
latitudinal position of the place
revolution of the earth on a tilted axis
Hint: Revolution + Rotation on a Tilted Axis = = Variation in seasons = = Variation in Day time and Night time
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The Earth rotates on its axis once every 24 hours. This rotation causes the day and night cycle. The Earth’s axis is tilted at an angle of 23.5 degrees relative to its orbital plane. This tilt causes the seasons.
The Earth’s day is divided into 24 hours, each of which is divided into 60 minutes, and each minute is divided into 60 seconds. The Earth’s year is the time it takes the Earth to orbit the Sun once. It is approximately 365.25 days long.
The solstices and equinoxes are the four days of the year when the Sun is at its highest or lowest point in the sky. The summer solstice occurs on June 21st, the winter solstice occurs on December 21st, the spring equinox occurs on March 20th, and the fall equinox occurs on September 22nd.
The Coriolis effect is an apparent deflection of objects moving in a straight line on a rotating object. It is caused by the Earth’s rotation. The Coriolis effect is responsible for the clockwise rotation of hurricanes in the Northern Hemisphere and the counterclockwise rotation of hurricanes in the Southern Hemisphere.
Precession of the equinoxes is the slow change in the orientation of the Earth’s axis over time. It is caused by the gravitational pull of the Sun and Moon on the Earth. Precession causes the Earth’s axis to wobble like a top. It takes about 26,000 years for the Earth’s axis to complete one precession cycle.
Tidal locking is the phenomenon in which one celestial body is tidally locked to another. This means that the same side of the body always faces the other body. The Earth is tidally locked to the Sun, which means that the same side of the Earth always faces the Sun.
The Earth’s rotation has a number of effects on the Earth’s Climate. The Earth’s rotation causes the Earth’s atmosphere to move in a circular motion. This motion causes the Earth’s weather patterns. The Earth’s rotation also causes the Earth’s seasons.
The Earth’s rotation also has a number of effects on the Earth’s life. The Earth’s rotation causes the Earth’s day and night cycle. This cycle is important for Plants and animals that need sunlight to survive. The Earth’s rotation also causes the Earth’s seasons. The seasons are important for plants and animals that need to migrate or change their behavior in order to survive.
The Earth’s rotation also has a number of effects on human activity. The Earth’s rotation causes the Earth’s day and night cycle. This cycle is important for human activities such as transportation and agriculture. The Earth’s rotation also causes the Earth’s seasons. The seasons are important for human activities such as tourism and recreation.
The Earth’s rotation is a fundamental part of the Earth’s system. It has a number of effects on the Earth’s climate, life, and human activity. The Earth’s rotation is a natural process that has been happening for billions of years. It is not something that can be changed or stopped.
What is the difference between rotation and revolution?
Rotation is the turning of a body on its axis, while revolution is the movement of a body around another body. For example, the Earth rotates on its axis once every 24 hours, while it revolves around the Sun once every 365.25 days.
What is the Earth’s axis?
The Earth’s axis is an imaginary line that runs through the center of the Earth from pole to pole. The Earth’s axis is tilted at an angle of 23.5 degrees relative to the plane of its orbit around the Sun. This tilt is responsible for the seasons.
What is the Earth’s orbit?
The Earth’s orbit is the path that the Earth takes around the Sun. The Earth’s orbit is elliptical, which means that it is not a perfect circle. The Earth’s distance from the Sun varies throughout the year, with the Earth being closest to the Sun in January and farthest from the Sun in July.
What is the Earth’s day?
The Earth’s day is the time it takes for the Earth to rotate once on its axis. The Earth’s day is 24 hours long.
What is the Earth’s year?
The Earth’s year is the time it takes for the Earth to revolve once around the Sun. The Earth’s year is 365.25 days long.
What is the Earth’s atmosphere?
The Earth’s atmosphere is the layer of gases that surrounds the Earth. The Earth’s atmosphere is made up of nitrogen (78%), Oxygen (21%), argon (0.9%), carbon dioxide (0.04%), and other gases.
What is the Earth’s surface?
The Earth’s surface is made up of land and water. The Earth’s landmasses are called continents, and the Earth’s Oceans are called seas. The Earth’s surface is also covered in ice, snow, and Glaciers.
What is the Earth’s core?
The Earth’s core is the innermost part of the Earth. The Earth’s core is made up of two parts: the solid inner core and the liquid outer core. The Earth’s core is very hot, and it is responsible for the Earth’s Magnetic Field.
What is the Earth’s mantle?
The Earth’s mantle is the layer of rock that lies between the Earth’s crust and the Earth’s core. The Earth’s mantle is made up of solid rock, but it is very hot and can flow like a liquid. The Earth’s mantle is responsible for the movement of the Earth’s tectonic plates.
What is the Earth’s crust?
The Earth’s crust is the outermost layer of the Earth. The Earth’s crust is made up of solid rock, and it is divided into two types: continental crust and oceanic crust. Continental crust is thicker and less dense than oceanic crust.
What is the Earth’s gravity?
The Earth’s gravity is the force that attracts objects to the Earth. The Earth’s gravity is caused by the mass of the Earth. The Earth’s gravity is strong enough to hold the Earth’s atmosphere in place, and it is also strong enough to keep the Earth’s oceans from flowing off into space.
What is the Earth’s magnetic field?
The Earth’s magnetic field is a field of force that surrounds the Earth. The Earth’s magnetic field is generated by the movement of molten iron in the Earth’s core. The Earth’s magnetic field protects the Earth from harmful radiation from the Sun.
What is the Earth’s climate?
The Earth’s climate is the Average weather conditions on Earth. The Earth’s climate is affected by the Earth’s orbit around the Sun, the Earth’s tilt, the Earth’s atmosphere, and the Earth’s oceans. The Earth’s climate has changed throughout history, and it is currently changing due to human activity.
Sure. Here are some multiple choice questions about the Earth:
The Earth is a: (A) planet (B) star (C) moon (D) comet
The Earth is the third planet from the Sun. (A) True (B) False
The Earth is the only planet in The Solar System that is known to support life. (A) True (B) False
The Earth’s atmosphere is made up of: (A) nitrogen (B) oxygen (C) argon (D) all of the above
The Earth’s surface is covered in: (A) water (B) land (C) ice (D) all of the above
The Earth’s core is made up of: (A) iron (B) nickel (C) both iron and nickel (D) none of the above
The Earth’s magnetic field protects us from: (A) solar radiation (B) cosmic rays (C) both solar radiation and cosmic rays (D) none of the above
The Earth’s rotation causes: (A) day and night (B) the seasons (C) both day and night and the seasons (D) none of the above
The Earth’s orbit around the Sun takes: (A) 365 days (B) 365.25 days (C) 365.2422 days (D) 365.24222 days
The Earth’s tilt on its axis causes: (A) day and night (B) the seasons (C) both day and night and the seasons (D) none of the above
