Hurry up! ! Junior high school science: explain that when the earth rotates, there will be days and nights as different as the vernal equinox and the summer solstice on the earth! It's best to explain

Hurry up! ! Junior high school science: explain that when the earth rotates, there will be days and nights as different as the vernal equinox and the summer solstice on the earth! It's best to explain it according to the pictures. Because there is an included angle of 23 26' between the earth's orbital plane (ecliptic plane) and the equatorial plane, when the earth rotates and revolves, the direct point of the sun (

The direct point of the sun is where the incident angle of sunlight on the earth's surface is 90 degrees) moves regularly between the tropic of cancer,

The law of activity is:

Equinox (March 2 1 or so)

The direct point of the sun is on the equator, and then it moves north.

Summer solstice (around June 22nd)

The direct point of the sun is on the tropic of cancer, and then moves south.

Equinox (around September 23rd)

The direct point of the sun is at the equator, and then it continues to move south. During the winter solstice (around 65438+February 22nd), the direct point of the sun is on the tropic of Capricorn, and then moves northward. In this way, the length of day and night in different solar terms is different. In addition, the extreme day and night phenomenon at the poles is also related to the position of the direct point of the sun, and the reason is the same. As for pictures, they should be clearly described in textbooks.