Why is the shadow getting shorter and shorter from the solstice in summer to the solstice in winter?

From the solstice in summer to the solstice in winter, the direct point of the sun moved from the northern hemisphere to the southern hemisphere, and the shadow became longer as the sun got farther and farther away from us.

In a day, the sun is the highest and the shadow is the shortest at noon. In a year, the height of the sun in the same place is different every day. The sun is the highest from summer to the sun, so the shadow is the shortest. From winter to the sun, the height of the sun is the lowest, the height angle of the sun is the smallest, and the shadow is the longest. From the solstice in summer to the solstice in winter, the shadow becomes shorter and shorter.

The direct point of the sun moves between the tropic of cancer in a one-year cycle. From summer to the sun, the sun shines directly on the Tropic of Cancer (23 26' north latitude), the noon sun height to the north of the Tropic of Cancer reaches the maximum, and the noon sun height in the whole southern hemisphere reaches the minimum. On the winter solstice, the sun shines directly on the tropic of Capricorn (at 23 26' south latitude), and the situation in the north and south is opposite to the summer solstice. The rest of the time is the transition between these two States. When the sun shines directly on the tropic of Capricorn, it coincides with the solar term of winter solstice in northern China. At this time, the solar altitude angle is 43, which is the minimum value in a year. Due to the rotation of the earth, the apparent motion of the sun (rising in the east and setting in the west), that is, the daily variation of the height of the sun.