Most asked Science Questions and Answers - Part 1

Here we are going to look at some of the most asked science questions and answer them in a scientific way. On the way of our journey to understand these questions, I will talk about some least known fun facts.

check out top 8 scary space images:- click here.

1. Why is the sky blue?

As we know earth is surrounded by the atmosphere (Mixture of gases mainly, nitrogen (78%) and oxygen (20.9%)).

Image Credits: NASA

White light is made up of 7 colours (violet, indigo, blue, green, yellow, orange, red). light act as a particle and a wave. Taking the wave nature of light into consideration, violet has the shortest wavelength and red has the longest wavelength.

when sunlight passes through the atmosphere. The longer wavelengths like red, orange, etc pass through our atmosphere and appear to us as regular sunlight. The shorter wavelengths like violet, blue get scattered in different directions by the molecules of gas in our atmosphere. Now you might think violet gets scattered more than why is the sky not violet. The following are the reasons:-

• Near the bottom of the atmosphere, there are more blue rays than violet because violet gets strongly scattered in the upper atmosphere.
• Our eye is more sensitive to blue compared to violet.

2. Why does the sun and moon look the same size?

From the surface of the earth, we see that sun and moon look the same size. 

The sun’s diameter is about 400 times larger than that of the moon but the sun is also about 400 times farther away because of this reason the sun and moon appear the same size from earth. 

We can witness a total solar eclipse because the sun and the moon appear the same size from earth. 

They are not always the same size as the distance between earth and sun, earth and moon changes (results in an annular eclipse).

FUN FACT:

• Many years back (about 1.6 billion years) the moon was closer than it is today, therefore there were no annular eclipses back then.
• Since the moon is moving away from earth by about 4 cm every year, after about 1.2 billion years we will no longer have total solar eclipses.
• Did you know there is a theory which says our moon is hollow and is an ancient alien warship. click here to check it out.

3. How do flies walk on the ceiling?

Flies and many other insects can walk or hold walls, ceiling, and even smooth surfaces like glass doors.

They can do this because they have a large number of tiny hairs on the bottom surface of their feet (check the image below, click on the image to zoom in). Even though surfaces that look smooth to us, they have many microscopic bumps and crevices, which serve as footholds for the tiny hair. 

Micrograph of a fly's sticky foot pad
image credits: Arlo James Barnes

They have claw like structures at the end of their legs that help the insect hold on to different types of surfaces. They also have sticky pads that contain numerous hairs that produce a glue-like substance made of sugars and oils. This oily substance helps them to stick onto smooth surfaces. 

4. How are rainbows made?

We know white light is made up of 7 colours (violet, indigo, blue, green, yellow, orange, red). The colours that make up white light are the same colours that we see in a rainbow. 

We know that wavelength differs from colour to colour (see the first question in this post for more about it). When white light pass-through a water drop they bend, this process is called refraction. The angle by which they bend depends upon the wavelength.

Angle by which a ray bends (angle of refraction) is inversely proportional to the wavelength of light. We know, violet has the shortest wavelength and red has the longest wavelength, therefore, red bends the least and violet bends more.

Due to this reason, white light splits into the 7 colours when they pass through water droplets. 

Primary and secondary rainbow with "Alexander's dark band" above the Lipno Reservoir (Údolní nádrž Lipno)
credits: Alexis Dworsky
(CC BY 2.0 DE)
https://creativecommons.org/licenses/by/2.0/de/deed.en

A double rainbow occurs when both the primary and secondary rainbows are visible. All rainbows are double rainbows, Most of the time we only spot primary rainbow because the secondary bow is always fainter than the primary. Primary rainbows have violet on the inside to red on the outside whereas secondary rainbows have red on the inside and violet on the outside.

FUN FACT:

• From above the earth (like from an aeroplane), it is sometimes possible to see a rainbow as a full circle.

5. Will sun ever stop shining?

In short, yes, the sun will stop shining in about 5 billion years.

The sun shines due to nuclear fusion in its core. Nuclear fusion is a process in which 2 or more lightweight nuclei collide to form a heavier one accompanied by the release of energy (as heat and light). In about 5 billion years, the sun will run out of fuel for nuclear fusion. 

FUN FACT:

• The sun is getting brighter as time passes. Sun is already 30% brighter compared to when the sun was born.
• Due to this, in about 2.5 to 3 billion years, the surface temperature of the earth will exceed the boiling point of water. 

If you would like to read about gravitational lens click here.

We might think these are very simple science questions, but these kind of questions always leads to some new discoveries which results in better understanding of our universe.