To summarize the law of change in the length of day and night, what is the law of change in the leng

1. The vernal equinox points to the summer solstice.

Northern Hemisphere. The days are long and the nights are short.

The length of day and night is equal on the vernal equinox, and the length of the day continues to increase, until the summer solstice has the longest day and the shortest night. Polar days begin to appear at the North Pole on the vernal equinox.

The summer solstice polar day extends to the entire Arctic Circle.

Southern Hemisphere: Short days and long nights.

The spring equinox has an equal length of day and night, and the length of the day continues to shorten, until the summer solstice has the shortest day and the longest night. The Antarctic Pole of the vernal equinox begins to appear at the Polar Night.

The polar night of the summer solstice extends to the entire Antarctic Circle.

2. The summer solstice points to the autumn equinox.

Northern Hemisphere: Longer days and shorter nights.

The length of the day continues to shorten, and by the autumnal equinox the length of day and night is equal. The polar day range of the summer solstice begins to shrink until the autumnal equinox disappears completely.

Southern Hemisphere: Short days and long nights.

The length of the day continues to increase, and by the autumnal equinox, the length of day and night is equal. The polar day range of the summer solstice begins to shrink until the autumnal equinox disappears completely.

3. The autumnal equinox points to the winter solstice.

Northern Hemisphere: Short days and long nights.

The length of the days continues to shorten, and the days are the shortest and the nights are the longest on the winter solstice. Polar nights begin to appear at the Arctic at the autumnal equinox, and the polar nights on the winter solstice extend to the entire Arctic Circle.

Southern Hemisphere: Longer days and shorter nights.

The length of the day continues to increase, and the longest day and shortest night are on the winter solstice. Polar days begin to appear at the South Pole at the autumnal equinox, and the polar days expand to the entire Antarctic Circle by winter.

4. The winter solstice points to the spring equinox.

Northern Hemisphere: Short days and long nights.

The length of the day continues to increase until the vernal equinox is equal in length and night. The range of the polar night at the North Pole begins to shrink on the winter solstice, and disappears completely at the vernal equinox.

Southern Hemisphere: Longer days and shorter nights.

The length of the day continues to decrease until the equinox the length of day and night is equal. On the winter solstice, the polar day range of the South Pole begins to shrink, and by the autumnal equinox it disappears completely.

1. On the day of the spring and autumn equinoxes, the global day and night are of equal length.

2. On the summer solstice, the days and nights in the northern hemisphere are short and the longest days and the shortest nights in the year, the southern hemisphere has short days and long nights and the shortest days and longest nights in the year, and the days are longer and shorter in the north, the shorter the nights are the farther south, the polar days appear in the Arctic Circle and its north, and the polar nights appear in the Antarctic Circle and its south; The winter solstice is the opposite.

3. Between the spring equinox and the autumn equinox, the days and nights in the northern hemisphere are shorter and the longer the days and shorter the nights are the further north they go. The Southern Hemisphere is the opposite. Between the autumnal equinox and the vernal equinox, the days are shorter and the nights are longer in the northern hemisphere, and the days are shorter and the nights are longer as the further north they go. The Southern Hemisphere is the opposite.

The pattern of variation in the length of day and night is:

1. The vernal equinox points to the summer solstice.

In the Northern Hemisphere, the days are longer and the nights are shorter, the spring equinox is equal in length and the summer solstice is the longest and the shortest night. Polar daylight occurs in the North Pole and the polar day range is expanding. The Southern Hemisphere has short days and long nights.

And the nights are lengthening and the days are shortening, the spring equinox days and nights are of equal length, and the summer solstice night is the longest and the day is the shortest. Polar nights occur in Antarctica, and polar nights are expanding.

2. The summer solstice points to the autumn equinox.

In the Northern Hemisphere, the days are shorter and the nights are longer, the autumnal equinox is equal in length and the summer solstice is the longest and the night is the shortest. Polar daylight occurs at the North Pole, and the polar day range is decreasing. The Southern Hemisphere has short days and long nights.

And the night is shortening and the day is lengthening, the autumn equinox day and night are equal in length, and the summer solstice night is the longest and the day is the shortest. Polar nights are occurring in Antarctica, and the range of polar nights is decreasing.

3. The autumnal equinox points to the winter solstice.

In the Northern Hemisphere, the days are shorter and the nights are longer, the days are shortening and the nights are lengthening, the autumnal equinox is equal in length and the winter solstice is the longest and the shortest is the day. Polar nights are occurring in the North Pole, and polar night ranges are expanding. In the Southern Hemisphere, the days are longer and the nights are shorter.

And the night is shortening, the day is lengthening, the autumn equinox day and night are equal in length, and the winter solstice day is the longest and the day is the shortest. Polar day is occurring in Antarctica, and polar night is expanding.

4. The winter solstice points to the spring equinox.

In the Northern Hemisphere, the days are shorter and the nights are longer, the days are shorter, the spring equinox is equal in length and the winter solstice is the longest and the shortest is the day. Polar night is occurring in the North Pole, and the polar night is shrinking. In the Southern Hemisphere, the days are longer and the nights are shorter.

And the night is lengthening and the day is shortening, the spring equinox day and night are equal in length, and the winter solstice day is the longest and the day is the shortest. Polar day is occurring in Antarctica, and the polar night is shrinking.

Northern Hemisphere. The length of day and night changes:

From the spring equinox to the summer solstice, the days gradually become longer and the nights gradually shorter, the days are longer and the nights are shorter, and the days are the longest and the shortest nights are on the summer solstice.

From the summer solstice to the autumnal equinox, the night gradually becomes longer, the day becomes shorter and the night is shorter at this stage, and the day and night are equal on the day of the autumnal equinox.

From the autumnal equinox to the winter solstice, the nights gradually become longer, the days are shorter and the nights are longer at this stage, and the days are the longest and the nights are the shortest on the winter solstice.

From the winter solstice to the vernal equinox, the days gradually become longer and the nights gradually shorter, the days are short and the nights are longer at this stage, and the day and night are equal on the day of the vernal equinox.

The Southern Hemisphere is the opposite of the Northern Hemisphere.

1. The vernal equinox points to the summer solstice.

Northern Hemisphere: Longer days and shorter nights.

Southern Hemisphere: Short days and long nights.

2. The summer solstice points to the autumn equinox.

Northern Hemisphere: Longer days and shorter nights.

Southern Hemisphere: Short days and long nights.

3. The autumnal equinox points to the winter solstice.

Northern Hemisphere: Short days and long nights.

Southern Hemisphere: Longer days and shorter nights.

4. The winter solstice points to the spring equinox.

Northern Hemisphere: Short days and long nights.

Southern Hemisphere: Longer days and shorter nights.

Manifestations of the Earth's rotation.

1.Due to the rotation of the earth and the irradiation of the sun, the phenomenon of day and night changes occurs on the earth. To illustrate this phenomenon, the dividing line between the day and night hemispheres on Earth is called the morning and dusk line, which is the line between the sun's rays and the earth's tangent point.

2.The textbook says that at any one time, the sun can only illuminate half of the earth's surface. There are a number of prerequisites here:

First of all, it is believed that the sun is a point of light, and the sun's rays are shining parallel light, which illuminates exactly half of the earth. In fact, the sun is a circular plane with an apparent radius of 16, so the light from the edge point and the center point of the circular plane will be at different tangent positions on the earth, resulting in different morning and dusk lines, and from the perspective of the sun as a whole, the morning and dusk lines will expand.

3.Second, it is believed that sunlight travels in a straight line to the earth's surface. In fact, the earth is surrounded by a thick atmosphere, and the atmosphere has a refractive effect on sunlight, and the atmosphere can be regarded as a lens, and its refractive index of light is different from the refractive index outside the atmosphere, and the direction of the sun's rays will change when they enter.

Light that does not hit the ground in a straight line will also hit the ground due to refraction, so that the morning and dusk lines may expand again.34 Third, it does not take into account the scattering effect of the atmosphere on light, i.e., the shadow of morning and dusk. It occurs at the edge of the night hemisphere extending approximately 6 °, so that people feel that the night is shorter than it actually is, and people live it'The effect is greater than that of the morning and dusk line (16 +34 = 50).

4.In the process of the earth's movement, the earth rotates around the earth's axis, and in the process of rotation, because the earth is an opaque sphere, the hemisphere facing the sun is day, and the hemisphere facing away from the sun is night, the earth keeps rotating, resulting in the phenomenon of day and night. In the process of rotation, the earth's axis is inclined to revolve around the sun, causing the direct point of the sun to move back and forth between and, and the earth's surface at different latitudes to obtain different light and heat, resulting in the change of the four seasons.