Why is the Sky Blue? – A Funny Answer to a 3-5 Year Old Question
Undoubtedly, the sight of a stunning blue sky is something to marvel at; but when your 3-5 year old asks why the sky is blue, it’s essential that they receive honest responses.
Our planet boasts something the moon doesn’t: air. When light passes through our atmosphere it scatters, with blue wavelengths dispersing more widely than other colors.
The Sun
If you ask a kindergartener why the sky is blue, they might respond with “It’s blue because the oceans are blue.” Although this answer provides part of an explanation for its hue, this does not fully explain its hue; its hue comes from how light is scattered by air molecules in our atmosphere – not ocean color itself.
Scientists took years to pinpoint why the sky is blue. To do so, they needed to apply some basic principles of physics: all light travels along a generally straight path unless something interferes with it like mirrors or prisms; this phenomenon is known as Rayleigh scattering; in 1871 a scientist named Lord Rayleigh recognized that tiny particles in Earth’s atmosphere scatter light all directions at random while some tend to do it more than others.
Why does the sky appear blue most of the time? Sunlight entering Earth’s atmosphere is scattered more by blue part of spectrum than any other color (including purple), making the sun appear predominantly blue in sky.
Violet and red light tends to be scattered less by air molecules, giving rise to more red-tinged and orange hues in the sky than during daytime, when sun is higher in the sky at sunset or sunrise.
One other interesting point about the Moon is that, without an atmosphere, its colors do not differ much from other planets that we’ve visited.
Next time you gaze upon the sky, think about all the factors that contribute to its color: sunlight, gases, and dust particles in the atmosphere. Don’t forget to tip your cap to Toronto Blue Jays; they deserve our congratulations since winning two World Series since 1977!
The Earth’s Atmosphere
Our planet’s atmosphere is a layer of gases enveloping Earth that includes nitrogen and oxygen among other gases, among others. Although they don’t possess any color of their own, our atmosphere interacts with different wavelengths of light; longer wavelengths (such as red and orange light rays ) tend to be absorbed by nitrogen and oxygen molecules while shorter wavelengths like blue tend to scatter off them instead. This phenomenon known as Rayleigh Scattering gives our sky its characteristic blue hue.
If you ever take an airplane ride, you might notice that the sky seems brighter above than below you. That is because sunlight coming from below the horizon has to travel further through our atmosphere before reaching your eyes – meaning shorter wavelengths like blue may become scattered or have difficulty reaching you than longer wavelengths such as red. Our sky appears blue because both our Sun emits more blue light and our eyes have better detection for seeing blue than violet light.
As sunlight traverses our atmosphere, it interacts with water droplets found in clouds, reflecting its light in many different directions and producing various hues – most prominently blue due to larger water molecules than atmospheric particles that scatter its light.
Rainbows appear when light shines through water drops, reflecting off of each drop and reflecting back towards our eyes, where our brain interprets it to form what is seen as a rainbow.
Our atmosphere is an integral component of life on Earth. It protects us from radiation coming from the Sun, helps regulate temperature and ensures clean drinking water supplies. The ozone layer absorbs UV rays that could harm living tissues; higher layers protect us from meteorites and the solar wind which blows across space from a solar flare or solar storm; it extends even beyond Earth itself and can be observed from satellites that orbit around our planet.
Rayleigh Scattering
An inviting sunny day is the ideal opportunity for outdoor activities and relaxing on the grass, but when standing on an atmosphere-less planet like Mars or Mercury it does not look blue at all! Why is that? Rayleigh scattering may be responsible.
Rayleigh scattering is the process by which electromagnetic radiation, such as light, is dispersed by molecules in our atmosphere. This occurs because molecules are much smaller than the wavelength of light they collide with; wavelength is measured as distance between two consecutive points on a waveform). When white light strikes atmospheric molecules it may scatter in multiple directions, with the most commonly chosen being that which corresponds with shorter wavelengths – that is closer to blue ends of visible spectrum.
If the molecule in question is gaseous such as nitrogen or oxygen, then only blue and red light will be scattered by it – violet photons being more quickly released than their higher energy blue counterparts – leading to greater dispersion than any other colors.
Eyes are particularly attuned to blue, so our brains tend to perceive it as brighter and lighter shades than other colors. Furthermore, blue molecules emitting nitrogen molecules and being absorbed by oxygen molecules has an enormous effect on making the sky appear bluer than it actually is.
As can be seen, there’s much going on here, but the key point is that blue hue of the sky comes from only part of the sunlight passing through our atmosphere, while all other wavelengths (ie rainbow) pass completely unaffected and simply pass into space without being scattered by Earth’s atmosphere. This explains why Moon doesn’t have blue skies and stars appear yellow in space – should another planet’s atmosphere have been thicker it would look even different still!
The Rainbow
The Sun emits light of all different colors, and when it enters our atmosphere it gets scattered in many directions. The oxygen and nitrogen molecules in the air are just the right size to scatter most of the high-energy blue light, leaving behind most of the less-energized violet and red light. The human eye is sensitive to all of these wavelengths, but it tends to focus on the violet and red ones more than the blue ones.
On a clear day, the sky is often bright blue and looks like an ocean you could dive into. But why is it blue? The answer has to do with the colorless gases in our atmosphere. The atmosphere is made up of a combination of mostly nitrogen and oxygen, with traces of water vapor, carbon dioxide, and other trace gases. These gases don’t reflect sunlight, but they do keep our planet warm.
As sunlight moves through the atmosphere, it hits gas molecules and gets scattered in all directions. When it reaches the bottom of our atmosphere, it combines with air particles to make up a rainbow that we can see. The same thing happens when you shine light through a prism.
You may notice that the blue of the sky is lighter closer to the horizon than it is overhead. This is because the light has had to travel through more of our atmosphere to reach the horizon. This means more of the blue wavelengths have been scattered away, making it easier for the longer red and orange wavelengths to get through.
The sky is also more colorful at sunrise and sunset. This is because the Sun is lower near the horizon when it rises and sets, so the light has to travel through more of our atmosphere. This causes the blue wavelengths to scatter more, which leaves more of the red and orange wavelengths to reach your eyes.
The sky is blue because it reflects most of the sunlight that hits it. However, there are other factors that influence its color. For example, clouds can look yellow, white, or gray and affect how much sunlight is reflected. You can also see the colors of the rainbow in the sky if you look carefully enough, especially at sunrise and sunset.