Why does the energy from the sun decrease as the solar angle decreases?
The energy from the sun decreases as the solar angle decreases because of the way sunlight interacts with the Earth's atmosphere. The solar angle refers to the angle at which sunlight strikes a particular location on Earth's surface. This angle determines the path length that sunlight has to travel through the atmosphere before reaching the ground.
When the sun is directly overhead (at a solar angle of 90 degrees), sunlight has to travel through a relatively shorter path of the atmosphere. As a result, there is less scattering, absorption, and reflection of sunlight by the atmospheric particles. Therefore, less energy is lost as sunlight reaches the Earth's surface.
As the solar angle decreases, however, sunlight has to travel through a longer path of the atmosphere. In this scenario, there is an increased likelihood of scattering, absorption, and reflection of sunlight by the atmospheric particles. These processes cause some of the sunlight's energy to be dispersed or absorbed, reducing the amount of energy that reaches the surface. This explains why the energy from the sun decreases as the solar angle decreases.
To understand this concept, you can perform a simple experiment. Place a piece of paper on the ground under direct sunlight when the sun is at a high angle (around noon). Observe the intensity and brightness of the sunlight hitting the paper. Then, repeat the experiment with the same piece of paper when the sun is at a lower angle in the morning or evening. You will notice that the intensity of the sunlight is lower, indicating a decrease in energy as the solar angle decreases.