Why does the sun appear red at sunrise ?

Explanation

### Step-by-Step Solution:

1. **Understanding the Position of the Sun**:
- At sunrise, the sun is positioned near the horizon. This means that the sunlight has to travel through a larger thickness of the Earth's atmosphere compared to when it is overhead.

2. **Nature of Sunlight**:
- Sunlight is composed of various colors, which can be represented by the acronym VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange, Red). Each color has a different wavelength, with red having the longest wavelength and violet having the shortest.

3. **Scattering of Light**:
- As sunlight enters the Earth's atmosphere, it interacts with air molecules and particles present in the atmosphere. This interaction causes scattering of light. Shorter wavelengths (like blue and violet) are scattered more than longer wavelengths (like red and orange).

4. **Path Length of Light**:
- During sunrise, the light from the sun travels through a greater distance in the atmosphere. This increased distance results in more scattering of the shorter wavelengths (blue and violet), allowing the longer wavelengths (red and orange) to dominate.

5. **Perception of Color**:
- As a result of this scattering, when we look at the sun during sunrise, the light that reaches our eyes is primarily red and orange. Hence, the sun appears red.

6. **Conclusion**:
- The red appearance of the sun at sunrise is primarily due to the scattering of shorter wavelengths of light in the atmosphere, which allows the longer wavelengths (red and orange) to be more visible.