If i could catch a rainbow,
I would just do it for you
And share with you it’s beauty,
On the days you are feeling Blue.
Rainbows are nature’s optical illusion.
It’s not possible unfortunately to catch a rainbow. They are not objects and are not located at specific distance from the observer that one can physically approach.
Rainbows stems from an optical illusion caused by any water droplets viewed from a certain angle relative to a light source.
They are user-specific and everyone sees a different rainbow.
Not all rainbows that occur in nature are multicolored. Under specific atmospheric conditions, one can spot the Mono-chrome rainbow i.e It has only one color.
PC : rodjonesphotography
A Moonbow / Lunar rainbow /White rainbow is a rainbow produced by light reflected off the surface of the moon (as opposed to direct sunlight) refracting off of moisture-laden clouds in the atmosphere / from waterfalls.
PC: GanMed64
Just as no two people see exactly the same rainbow, even if they’re standing next to each other, the few inches between your eyes make a difference in what you are viewing.
One can distinguish almost all colors in a rainbow but Indigo.
Legend has it that Newton included indigo because he felt that there should be seven rather than six colors in a rainbow due to his strong religious beliefs.
The Greeks and Romans thought a rainbow was the path made by Iris, the goddess of the rainbow, between heaven and earth, linking gods with humans. “Rainbow” in Latin is arcus iris or arcus pluvius, a “rainy arch”.
The iris of the eye is named after her, because of its colour.
The Greeks used the word “iris” to describe any coloured circle, such as the “eye” of a peacock’s tail. The flower called iris gets its name from the Greek, as does the chemical iridium (Ir), compounds of which are highly coloured. Iris is also the root of “iridescent”.
Place a linear polarizer over the camera whilst capturing a rainbow and you get pulsating rainbows.
Source
A double rainbow is a phenomenon in which two rainbows appear. They are caused by a double reflection of sunlight inside the raindrops. Similarly multiple rainbows are a possibility as well.
Observe that the colors in the second rainbow are inverted because the light is reflected twice inside the water droplet
PC: Janbazian
This video of a man witnessing a double rainbow for the first time went viral, featuring on numerous popular talk shows. Pure ecstasy!
Whilst standing on earth, we see rainbows as magical arcs across the sky, but rainbows are full circles. The bottom part of the full circle is usually blocked by the horizon.
Pilots however do not face this difficulty. Under the right sky conditions, pilots are spectators to one of nature’s most beautiful spectacles - The full rainbow.
PC : Steve Kaufman
Everything has beauty, but not everyone sees it.
Have a great day!
It has been a blissful month in physics with the nobel prize for the work on gravitational waves and LIGO swiftly striking back with the detection of a neutron star merger.
At FYP! we have started to dwell a little bit into the essence of condensed matter physics while exploring some really cool science and engineering along the way.
Here’s what went down on FYP! this month:
Nobel prize in physics article on Gravitational waves
Gravitational waves, Light and Merging neutron stars
Paramagnets and Combinatorics
Diamagnetic levitation - Ig Nobel prize(2000)
Levitating frogs and superconductivity
Revisiting rolling shutter
Cooking with a computer (the importance of a heat sink on a computer)
Cartoon laws of physics
Beautiful proofs (#3) - Euler’s sum
Have a great day!
One of my math professors always told me:
Understand the concept and not the definition
A lot of times I have fallen into this pitfall where I seem to completely understand how to methodically do something without actually comprehending what it means.
And only after several years after I first encountered the notion of cross products did I actually understand what they really meant. When I did, it was purely ecstatic!
I mean this is one of the burning questions regarding the cross product and yet for some reason, textbooks don’t get to the bottom of this. One way to think about this is :
It is modeling a real life scenario!!
The scenario being :
When you try to twist a screw (clockwise screws being the convention) inside a block in the clockwise direction like so, the nail moves down and vice versa.
i.e When you move from the screw from u to v, then the direction of the cross product denotes the direction the screw will move..
That’s why the direction of the cross product is orthogonal. It’s really that simple!
Now that you get a physical feel for the direction of the cross product, there is another way of looking at the direction too:
Displacement is a vector. Velocity is a vector. Acceleration is a vector. As you might expect, angular displacement, angular velocity, and angular acceleration are all vectors, too.
But which way do they point ?
Let’s take a rolling tire. The velocity vector of every point in the tire is pointed in every other direction.
BUT every point on a rolling tire has to have the same angular velocity – Magnitude and Direction.
How can we possibly assign a direction to the angular velocity ?
Well, the only way to ensure that the direction of the angular velocity is the same for every point is to make the direction of the angular velocity perpendicular to the plane of the tire.
Problem solved!
That my dear friends is a CT scan machine. Stripped off all the body parts, you can see clearly see what goes on inside.
A computerized tomography (CT) or computerized axial tomography (CAT) scan combines data from several X-rays to produce a detailed image of structures inside the body.
CT scan of Brain
Pretty cool, don’t you think ?
Extras
Difference between MRI and CT scan
Why dont you spin the patient instead ? - Awesome reddit thread
Better quality gifs : here
Source Video: Micheal Jonnson
Thought this was important to post.
Flexible, wearable electronics require equally flexible, wearable power sources. In the journal Angewandte Chemie, Chinese scientists have introduced an extraordinarily stretchable and compressible polyelectrolyte which, in combination with carbon nanotube composite paper electrodes, forms a supercapacitor that can be stretched to 1000 percent in length and compressed to 50 percent in thickness with even gaining, not losing capacity.
Supercapacitors bridge the gap between batteries, which are merely energy-storing devices, and normal capacitors, which release and take up electric energy very quickly but cannot store so much energy. With their ability to charge and release large amounts of electric power in a very short time, supercapacitors are preferably used in regenerative braking, as power buffers in wind turbines, and, increasingly, in consumer electronics such as laptop computers and digital cameras. To make supercapacitors fit for future electrics demands like, for example, wearables and paper electronics, Chunyi Zhi from the City University of Hong Kong and his colleagues are searching for ways to endow them with mechanical flexibility. It can be achieved with a new electrolyte material: they developed a polyelectrolyte that can be stretched more than 10 times its length and compressed to half its thickness retaining full functionality, without breakage, cracking, or other damage to its material.
Read more.
Liquid penetrant testing (LT) is a non-destructive testing technique utilized to detect defects or discontinuities (such as cracks) on the surface of any type of non-porous material such as metal, plastics or ceramics. Liquid penetrant testing (also known as dye penetrant testing or penetrant testing) is primarily utilized in the industrial sector to test metal materials such as oil & gas pipelines and various metal machinery components to prevent failures or accidents. Some of the many defects that can be detected using this process include fatigue cracks, hairline cracks and porosity. A number of industries utilize liquid penetrant testing, including petrochemical, aerospace, engineering, automotive and many more.
Although liquid penetrant testing is the least technologically advanced method of non-destructive testing (with the others being ultrasonic testing, magnetic particle testing and radiography) – it is still widely used. That’s because liquid penetrant testing has the advantages of being low in cost, versatile and easy to perform. In fact, liquid penetrant testing requires very little training when compared to the other three main forms of non-destructive testing.
So exactly how does liquid penetrant testing work? The material to be tested must first be cleaned – usually using a simple spray cleaner that can be easily wiped off with a cloth or rag. A liquid penetrant solution is then applied to the surface of the material being tested using a simple aerosol spray from a can. The liquid is then left to soak for a predetermined length of time – and will eventually seep into or be drawn into any cracks or defects within the material being tested. After the appropriate amount of “soak time” has passed, the technician wipes the liquid penetrant off of the test object. A developer is then applied to the entire area being tested. The developer is usually a dry white powder such as chalk that is suspended in liquid and sprayed on in aerosol form. The developer then acts to draw out any liquid that may have seeped into a defect – giving a highly visible, colored indication on the surface of the test object.
Liquid penetrant testing relies solely on visual inspection – making the color contrast between the object being tested and the colored indication that reveals defects of utmost importance. For this reason, many technicians utilize fluorescents. This process is the same as conventional liquid penetrant testing, with the exception that a fluorescent penetrant is utilized and then the test object is viewed under ultraviolet light in a darkened environment. The result is that any defects present will glow brightly under the UV light – making visual inspection much easier.
Aside from the obvious advantages of being inexpensive and easy to use, liquid penetrant testing is also popular because of its versatility. In most cases, nothing more than three aerosol cans – cleaner, penetrant and developer – and a few cloths or rags are needed. This allows technicians to easily maneuver into tight spaces such as boilers or high places where ladders are required – easily completing testing in locations where other non-destructive testing techniques are difficult or impossible. For these reasons, liquid penetrant testing continues to be a viable and popular non-destructive testing method.
Tech Service Products is a stocking distributor of industrial supplies and non-destructive testing products such as liquid penetrant testing products.
Why are wheels circular? Why aren’t they triangular or square shaped?
That is a question that you might have pondered at some point in your life ( perhaps as a shower-thought? ) But sometimes even the most simple questions have the most elegant answers!
A square wheel can roll smoothly if the ground consists of evenly shaped inverted catenaries of the right size and curvature.
Well, it is the curve that a hanging cable assumes under its own weight when supported only at its ends. You find these everywhere!
Those chains on the pavement,
those hanging cables on a power transmission station,
or maybe a chandelier is of your type
All are catenaries!
Although it superficially resembles a parabola, it is NOT!
The mythbusters (like always) decided to give the four wheel vehicle a try.
And found out that, get this - with speed, a truck fitted with square wheels can deliver a relatively smooth ride, despite that bouncy start!
Well, although circular wheels still remain as the king of wheels, it is nice to know that we do have some alternatives up our sleeve!
Merry Christmas :)
PC: Etan J. Tal, kamel15
Fight waves with more waves!
A tsunami’s immense wall of water may not be stoppable. But there may be a way to take the ferocious force of nature down a few notches, using a pair of counterwaves.
If released at the right moment, a type of sound wave known as an acoustic-gravity wave could subdue a tsunami, applied mathematician Usama Kadri of Cardiff University in Wales reports January 23 in Heliyon. These acoustic-gravity waves, which reach deep below the ocean’s surface, can stretch tens or hundreds of kilometers and easily travel long distances at high speeds.
Understand the concept and not the definition.
If you have studied vectors, then the notion of a cross product is something that you might be familiar with.
Although it is taught in many colleges and schools in its mathematical glory, this post aims to supplement the same but with an real-life example.
The magnitude of the cross product is the area of the parallelogram with two sides A and B.
The orientation of the cross product is orthogonal to the plane containing this parallelogram.
I mean this is one of the burning questions regarding the cross product and yet for some reason, textbooks don’t get to the bottom of this.
It is modeling a real life scenario!!
The scenario being :
When you try to twist a screw inside a block in the clockwise direction like so, the nail moves down and vice versa.
i.e When you move from the screw from u to v, then the direction of the cross product denotes the direction the screw will move.
That’s why the direction of the cross product is orthogonal. It’s really that simple :D
Have a good day!
A2A : Anonymous
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