why is it cold in winter and hot in summer basing on physics knowledge
The temperature variations between winter and summer are primarily caused by the tilt of the Earth's axis and its orbit around the Sun, which are both governed by physics principles.
During winter, a particular hemisphere of the Earth (either the northern hemisphere or the southern hemisphere) is tilted away from the Sun. As a result, sunlight hits this tilted hemisphere at a lower angle, spreading its energy over a larger area, leading to less concentrated heat. Additionally, the sunlight travels through a greater portion of the Earth's atmosphere, resulting in more absorption and scattering, further reducing the heat reaching the surface. These factors combined result in reduced solar energy and lower temperatures during winter.
On the other hand, during summer, the same hemisphere is tilted towards the Sun. This angle gives a more direct path for the sunlight, focusing its energy over a smaller area. The sunlight also traverses a shorter path through the atmosphere, minimizing the absorption and scattering processes. Consequently, more solar energy reaches the surface, leading to higher temperatures during summer.
It's important to note that this explanation is a simplification of the complex physics behind seasonal variations. Factors such as ocean currents, atmospheric circulation, and regional geography also influence temperature patterns. Nonetheless, the tilt of the Earth's axis and its effects on sunlight distribution are fundamental aspects of the physics underlying the temperature differences between winter and summer.