How Does Sand From Sahara End Up In Your Windshield ?

You might be an engineer if you know how long a zeptosecond is. (It's a trillionth of a billionth of a second!) http://ow.ly/uUUb30caXrH 

These 17 Women Changed The Face Of Physics

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coolest physics thing that u know??

The coolest physics thing that I know keeps changing over time. But here is one that is extremely fascinating ( and also exaggerated for the effect ; but true! ):

Person living at the top of a skyscraper experiences time faster than one at the bottom

It is a known fact that the higher you are in the earth’s ** atmosphere, the lesser the effect of gravity is.

But the lesser the effect of gravity is, the faster the time ticks.

By how much you ask? Even if you live on the top floor of the Burj Khalifa  your entire life, you would have aged more only by a few milliseconds than your friends at the bottom. 

( Sure, doesn’t seem like much, but hell would break loose if we don’t consider this on the bigger scale of things )

This is known as Gravitational time dilation and is at the foundations of General Theory of Relativity. (More about this in an upcoming post)

Have a great day and thanks for asking!

EDIT: ** Lets just say hypothetically the earth is not spinning( just to ignore special relativistic effects) and we are looking at only the effects of height.

Impressive artwork.

Dr. Greg Dunn (artist and neuroscientist) and Dr. Brian Edwards (artist and applied physicist) created Self Reflected to elucidate the nature of human consciousness, bridging the connection between the mysterious three pound macroscopic brain and the microscopic behavior of neurons. Self Reflected offers an unprecedented insight of the brain into itself, revealing through a technique called reflective microetching the enormous scope of beautiful and delicately balanced neural choreographies designed to reflect what is occurring in our own minds as we observe this work of art. Self Reflected was created to remind us that the most marvelous machine in the known universe is at the core of our being and is the root of our shared humanity.

h-t New Scientist: Brain images display the beauty and complexity of consciousness

Nature manifests itself in patterns. The interweaving of math with these patterns produces euphoria

What do you see ? Let use know in the comments :)

Quench your thirst for knowledge with:

More about Pascals triangle and Binary Trees - Vihart

Scary Sierpinski Skull Time

Mathematical secrets of the pascal’s triangle

Code to generate Pascal’s triangle mod in Python

The ocean is where the aliens live.

Transcript under the cut.

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Chances of hypersonic travel heat up with new materials discovery

Researchers at The University of Manchester in collaboration with Central South University (CSU), China, have created a new kind of ceramic coating that could revolutionise hypersonic travel for air, space and defense purposes.

Hypersonic travel means moving at Mach five or above, which is at least five times faster than the speed of sound. When moving at such velocity the heat generated by air and gas in the atmosphere is extremely hot and can have a serious impact on an aircraft or projectile’s structural integrity. That is because he temperatures hitting the aircraft can reach anywhere from 2,000 to 3,000 °C.

The structural problems are primarily caused by processes called oxidation and ablation. This is the when extremely hot air and gas remove surface layers from the metallic materials of the aircraft or object travelling at such high speeds. To combat the problem materials called ultra-high temperature ceramics (UHTCs) are needed in aero-engines and hypersonic vehicles such as rockets, re-entry spacecraft and defence projectiles.

But, at present, even conventional UHTCs can’t currently satisfy the associated ablation requirements of travelling at such extreme speeds and temperatures. However, the researchers at The University of Manchester’s and the Royce Institute, in collaboration with the Central South University of China, have designed and fabricated a new carbide coating that is vastly superior in resisting temperatures up to 3,000 °C, when compared to existing UHTCs.

Composites: Papercrete

Composites are materials composed of other materials in combination, often with a matrix that binds together fibers of some kind. Papercrete gets its name from its components, paper and concrete, though it is technically composed of cement, not concrete. In papercrete, a composite of paper and cement, the cement makes up the binding matrix that holds the paper fibers together.

Paper is composed of a natural polymer, cellulose, the structure of which can be seen in the bottom image above and fibers of which can be seen in the top left and middle right images. The fibers get coated with cement, often Portland cement, and lend strength to the new material that could not be found in the cement alone. (Paper is not only made of cellulose, but it is a key component which makes papercrete possible. Aside from paper and cement, papercrete is also made with water and some form of sand or earth - other materials can be used as well, just like in concrete).

The material resulting from this mixture, papercrete, has excellent sound absorption, is flame and fungus retardant as well as bug and rodent repellent, and is relatively light. More flexible then rock or regular concrete, papercrete is useful in earthquake prone areas. Though not the best load-bearing material, papercrete is a great insulator. Like any composite however, the exact formula used to produce the material can alter the properties significantly. Adding sand or glass strengthens papercrete and makes it more flame retardant, but also increases its weight. 

One of the beneficial things about papercrete is that almost any paper can be used to create it - cardboard, magazine paper, junk mail, newspaper, and other forms. Some work better than others but almost all can be used. Using waste papers such as these prevents them from entering landfills and allows paper to be recycled in a different way. 

Downsides of papercrete include its lower strength and durability, as well as the fact that - as of now - there is no code or standardization to its manufacture or use, limiting the projects it can be used in. A fair amount of papercrete is made by individuals working on ‘do it yourself’ projects.

Sources: ( 1 - images 1, 2, 4, and 5 ) ( 2 ) ( 3 )

Image sources: (Middle left)

Why most metals are silver (but copper and gold aren’t)

If we want to understand what gives a metal its color we first need to understand a little bit about the definition of a metal. Metals are materials that experience metallic bonding - wherein the atoms are so close that there is a veritable “sea of electrons” in the substance. (This is also what makes metals conductors, but that’s another story). Basically each atom donates an electron or two that is free to flow throughout the material, unattached to any particular nucleus. 

This proximity leads to an overlap in the allowed energy levels of electrons (shown in the lower left hand image above); basically the higher empty electronic levels are so close to the uppermost filled levels (also called the Fermi level) that they form an essentially continuous band of allowed energies. 

Now, backtracking a little bit, color in a substance is caused when a material doesn’t absorb a particular wavelength of light. Because of the empty energy levels mentioned above, metals generally can absorb all wavelengths of light in the visible spectrum. This implies that a metal should look black, except that the excited electron can immediately fall back to the state that it came from, emitting exactly the same energy, causing a flat piece of metal to appear reflective. Thus, the reason why most metals are silver. (Also, the flatter a metal, the more reflective, thanks to diffuse vs. specular reflection).

For a few select metals, like copper and gold, the absorption and emission of photons are noticeably dependent on wavelength across the visible part of the spectrum. The graph in the lower right image above shows the reflectance of aluminum, silver, and gold, including wavelengths in the infrared and ultraviolet. Aluminum is pretty reflective overall, and silver is highly reflective in the visible region (about 400 to 700 nm), but gold clearly absorbs wavelengths about 500 nm or below. Thus, it most strongly reflects yellow, giving it its characteristic appearance. 

Sources: (first image), 2 (second image), 3 (third image), 4