Light reflects and disperses

Light "reflects."

What causes a distant mountain to be distinctly reflected on the surface of a lake or pond?
The sunlight illuminating a mountain reflects in several directions. This phenomenon is referred to as reflected light. Our eyes see the mountain by catching light reflected from it, which immediately enters our eyes, and subsequently generating a picture of this reflected light on the retina via the eye's lens.
When a lake or pond is situated between our eyes and a mountain, the light emanating from the mountain reflects off the surface of the lake or pond. When the surface is tranquil, devoid of wind, and uniformly flat, akin to mirrors and glass, the angle of incident light (angle of incidence) is equal to the angle of reflected light (angle of reflection). This phenomenon is known as specular reflection or mirror reflection. When the surface is positioned optimally, allowing light reflected specularly to directly reach our eyes, we may perceive a crisp, clear image of the mountain mirrored on the surface.

Incidentally

If the surface is uneven or irregular, the direction of the reflected light fluctuates based on the surface position, leading to a distorted image of the mountain reflected on the water's surface.

Light "disperses"

What accounts for the sky's blue hue on clear days and its crimson appearance throughout the evening?
Solar radiation reaches the Earth after traversing space, scattering upon contact with the many particles and molecules in the atmosphere. A portion of this light reflects back into deep space, while the remaining reaches the Earth's surface after traversing the atmosphere. The degree of light scattering is contingent upon its wavelength, and within the visible spectrum, blue light is dispersed more intensively. This explains why the sky seems blue to our eyes during daylight.
 

Conversely

During dawn and sunset, the sky may exhibit hues of orange, pink, or red to human perception. This occurs because a lower position of the sun increases the distance light travels through the atmosphere, resulting in the scattering and attenuation of blue light. Consequently, the residual red or orange light reaches our eyes.