Why is the sky blue? The answer lies in the combination of light and the Earth's atmosphere. The atmosphere is a mixture of gas molecules and other materials that surrounds the earth; it is mostly made of nitrogen gas, with about 78 percent and 21 percent of oxygen. The composition of the atmosphere may vary from place to place; the atmosphere may contain more water near the ocean, and the atmosphere may contain more dust particles near erupted volcanoes. It is also worth knowing that the atmosphere is denser or thicker near the Earth and gradually blends into a thinner and thinner layer as it moves up.
Visible light is a type of energy that allows us to see around us. It travels in the form of an electromagnetic wave. Without light, there would be no objects, no colours, and no texture for us to sense through our eyes. It makes you think: if we evolved without light, would we need eyes? Not to get distracted, sun light is most of the time perceived as white light. However, it is not; this light is a blend of many colours, as you probably experienced in high school physics with the splitting of light with a prism or the rainbow in the sky after the rain.
Note similar effects as the light travels through space in a straight line and eventually strikes dust particles or gas molecules. This brings us to the colour spectrum. One end of the spectrum has reds that gradually change to oranges, yellows, greens, blues, indigos, and lastly, violets. Each colour in the spectrum has a different wavelength, frequency, and energy. The shortest wavelengths in the visible spectrum are violets, and the longest are reds. A short wavelength also means high frequency and energy, and a long wavelength means low frequency and energy.
The blue sky is the result of scattering. When the light moves through the atmosphere, longer waves pass through. The blue light, which is closer to violet and therefore has a shorter wavelength, is absorbed by the gas molecules and then radiated and scattered in different directions all around the sky. The scattering is so effective that wherever you look in the sky, you see blue.
~ Anna
Visible light is a type of energy that allows us to see around us. It travels in the form of an electromagnetic wave. Without light, there would be no objects, no colours, and no texture for us to sense through our eyes. It makes you think: if we evolved without light, would we need eyes? Not to get distracted, sun light is most of the time perceived as white light. However, it is not; this light is a blend of many colours, as you probably experienced in high school physics with the splitting of light with a prism or the rainbow in the sky after the rain.
Note similar effects as the light travels through space in a straight line and eventually strikes dust particles or gas molecules. This brings us to the colour spectrum. One end of the spectrum has reds that gradually change to oranges, yellows, greens, blues, indigos, and lastly, violets. Each colour in the spectrum has a different wavelength, frequency, and energy. The shortest wavelengths in the visible spectrum are violets, and the longest are reds. A short wavelength also means high frequency and energy, and a long wavelength means low frequency and energy.
~ Anna
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