The Simple Physics Behind A Fidget Spinner

What have eclipses ever done for science? Quite a lot, actually!

The first measurement of the width of the Atlantic ocean in the 16th Century

When British settlers arrived in Virginia in the US, they weren’t sure how far across the globe they’d gone. They recorded the local time of a total eclipse of the moon - which is seen all across the night-time side of the planet. Their colleagues in London did the same, and when the travellers returned they could figure out the five hour time difference.

Edmond Halley discovered that the moon is moving away from the Earth

Halley realised you could back-calculate when previous eclipses would have occurred. But he noticed a mismatch between his predictions and the history books. The reason, he discovered, what that he was assuming the moon stayed the same distance from the Earth. It is actually getting further at about the rate your fingernails grow. And that means that one day (in a few million years, that is), the moon will be too far away to create any more total solar eclipses.

In 1919 a solar eclipse proved Einstein’s theory of relativity

Einstein’s theory predicted that the sun’s gravity should bend the light of nearby stars, meaning that in theory we should be able to see stars that are hidden just behind the sun. However, sunlight always blocks our view of these stars, and it was only during a solar eclipse that there was a short window to see if hidden stars were visible, as predicted. Astronomer Arthur Eddington travelled to West Africa and took photos that proved Einstein right.

Scientists still use solar eclipses today

It’s very hard to study the sun’s corona - a tenuous hot gas, which just one millionth of the light intensity of the sun. The shapes and lines of the corona show the nature of the sun’s magnetic field, and are only visible to study during an eclipse. NASA are also using this opportunity to help create the first thermal map of Mercury!

Want to know more? Watch our full video.

What is glass?

When most people think of glass, their mind probably jumps straight to windows. And perhaps they’ve heard that old myth - that glass is actually a liquid, not a solid.

So what is glass?

Well, you’ve probably seen something like this before:

The three common phases of matter - gas, liquid, and solid. But you’ll notice that the solid picture is labeled crystalline state. Most people consider glass to be a solid, but it doesn’t quite look like that.

Crystals have a well defined structure, exhibiting long-range order. Glass is what’s called an amorphous material, exhibiting only short-range order. 

Basically, glass is a different kind of solid:

The quartz shown above is an example of a crystalline material. The molecules of glass on the other hand are disordered - yet still solid. 

To create glass, the liquid melt has to be cooled fast enough to prevent the substance from crystallizing. This fast cooling locks the atoms or molecules in the disordered state that looks like the liquid phase. 

Characterizing a substance as a glass also means that this glass transition is reversible. 

While most glass is optically transparent, the properties depend on the composition of the glass. Most of what you see every day is soda-lime-silicate glass, but there are many different kinds of glasses, including sodium borosilicate glass (Pyrex), lead-oxide glass, and aluminosilicate glass.

Sources: x x

apparently one whale years ago was observed doing this for hours and now more and more whales in the area are seen copying it so we think it’s a whole new behavior and it seems to be a response to shrinking food sources.

Instead of expending any energy actively hunting, the whale just holds its mouth open wherever fish are being hunted by birds. To escape the birds, the fish try to hide in the whale’s mouth because it’s a darker area that looks like shelter. …They’re turning into giant, sea-mammal pitcher plants.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/mms.12557?referrer_access_token=bXLTS5BeSw_vlIKHkM0bYIta6bR2k8jH0KrdpFOxC654HjreJ8D19K86UreR5JPsSRb0CuGhiJSV1L1ht-N1Gf_K_1a9MREFzQGU9oJDNctsKDin_HXcYEdsLg3EbcTl

How did the Greeks know ?

Greeks had a strong geometric approach towards problems and as a result their methods are very intuitive.

In this post, we will look at the Method of exhaustion formulated by Archimedes that stands out as a milestone in the history of mathematics

Method of Exhaustion - Archimedes

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In order to find the bounds of pi, Archimedes came up with a remarkably elegant ‘algorithm’, which is as follows:

Lower bound

Inscribe a n-sided polygon in a circle —> Measure its perimeter(p) —> Measure its diameter(d) —> pi_min = p/d —-> Repeat with  n+1 sides.

Upper bound

Circumscribe a n-sided polygon in a circle —> Measure its perimeter(p) —> Measure its diameter(d) —> pi_max = p/d —-> Repeat with  n+1 sides.

And by following this procedure one could obtain the upper and lower bounds of pi !

Heres an animation made on geogebra for a circle of diameter 1. Watch how the lower and upper bounds vary.

Archimedes did this for a 96 sided polygon and found the value of pi  to be between 3.14103 and 3.1427. This is a good enough approximation for most of the calculations that we do even today!

Happy Holidays !

What is Liquid Penetrant Testing?

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.

Solar System: Things to Know This Week

Reaching out into space yields benefits on Earth. Many of these have practical applications — but there’s something more than that. Call it inspiration, perhaps, what photographer Ansel Adams referred to as nature’s “endless prospect of magic and wonder.“ 

Our ongoing exploration of the solar system has yielded more than a few magical images. Why not keep some of them close by to inspire your own explorations? This week, we offer 10 planetary photos suitable for wallpapers on your desktop or phone. Find many more in our galleries. These images were the result of audacious expeditions into deep space; as author Edward Abbey said, "May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view.”

1. Martian Selfie

This self-portrait of NASA’s Curiosity Mars rover shows the robotic geologist in the “Murray Buttes” area on lower Mount Sharp. Key features on the skyline of this panorama are the dark mesa called “M12” to the left of the rover’s mast and pale, upper Mount Sharp to the right of the mast. The top of M12 stands about 23 feet (7 meters) above the base of the sloping piles of rocks just behind Curiosity. The scene combines approximately 60 images taken by the Mars Hand Lens Imager, or MAHLI, camera at the end of the rover’s robotic arm. Most of the component images were taken on September 17, 2016.

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2. The Colors of Pluto

NASA’s New Horizons spacecraft captured this high-resolution, enhanced color view of Pluto on July 14, 2015. The image combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC). Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode.

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3. The Day the Earth Smiled

On July 19, 2013, in an event celebrated the world over, our Cassini spacecraft slipped into Saturn’s shadow and turned to image the planet, seven of its moons, its inner rings — and, in the background, our home planet, Earth. This mosaic is special as it marks the third time our home planet was imaged from the outer solar system; the second time it was imaged by Cassini from Saturn’s orbit, the first time ever that inhabitants of Earth were made aware in advance that their photo would be taken from such a great distance.

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4. Looking Back

Before leaving the Pluto system forever, New Horizons turned back to see Pluto backlit by the sun. The small world’s haze layer shows its blue color in this picture. The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles called tholins. This image was generated by combining information from blue, red and near-infrared images to closely replicate the color a human eye would perceive.

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5. Catching Its Own Tail

A huge storm churning through the atmosphere in Saturn’s northern hemisphere overtakes itself as it encircles the planet in this true-color view from Cassini. This picture, captured on February 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. The storm is a prodigious source of radio noise, which comes from lightning deep within the planet’s atmosphere.

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6. The Great Red Spot

Another massive storm, this time on Jupiter, as seen in this dramatic close-up by Voyager 1 in 1979. The Great Red Spot is much larger than the entire Earth.

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7. More Stormy Weather

Jupiter is still just as stormy today, as seen in this recent view from NASA’s Juno spacecraft, when it soared directly over Jupiter’s south pole on February 2, 2017, from an altitude of about 62,800 miles (101,000 kilometers) above the cloud tops. From this unique vantage point we see the terminator (where day meets night) cutting across the Jovian south polar region’s restless, marbled atmosphere with the south pole itself approximately in the center of that border. This image was processed by citizen scientist John Landino. This enhanced color version highlights the bright high clouds and numerous meandering oval storms.

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8. X-Ray Vision

X-rays stream off the sun in this image showing observations from by our Nuclear Spectroscopic Telescope Array, or NuSTAR, overlaid on a picture taken by our Solar Dynamics Observatory (SDO). The NuSTAR data, seen in green and blue, reveal solar high-energy emission. The high-energy X-rays come from gas heated to above 3 million degrees. The red channel represents ultraviolet light captured by SDO, and shows the presence of lower-temperature material in the solar atmosphere at 1 million degrees.

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9. One Space Robot Photographs Another

This image from NASA’s Mars Reconnaissance Orbiter shows Victoria crater, near the equator of Mars. The crater is approximately half a mile (800 meters) in diameter. It has a distinctive scalloped shape to its rim, caused by erosion and downhill movement of crater wall material. Since January 2004, the Mars Exploration Rover Opportunity has been operating in the region where Victoria crater is found. Five days before this image was taken in October 2006, Opportunity arrived at the rim of the crater after a drive of more than over 5 miles (9 kilometers). The rover can be seen in this image, as a dot at roughly the “ten o'clock” position along the rim of the crater. (You can zoom in on the full-resolution version here.)

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10. Night Lights

Last, but far from least, is this remarkable new view of our home planet. Last week, we released new global maps of Earth at night, providing the clearest yet composite view of the patterns of human settlement across our planet. This composite image, one of three new full-hemisphere views, provides a view of the Americas at night from the NASA-NOAA Suomi-NPP satellite. The clouds and sun glint — added here for aesthetic effect — are derived from MODIS instrument land surface and cloud cover products.

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Discover more lists of 10 things to know about our solar system HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Dissecting Iron Man Suit - An Engineering Analysis

Structural, energy, and thermal analysis of Iron Man Suits specifically Mark I to Mark XLVI which have the following capabilities in common: external armor, supersonic flight, hovering, weaponry, and decoy flares.

1. STRUCTURAL ANALYSIS 

Wear Resistant and Shock Absorbent Exoskeleton  The physical protective value of exoskeleton is its ability to resist any penetrative loads as well as any shock loads. However, the whole thickness of exoskeleton panels should not be too hard because it will pass on the external impact load into the suit’s internal hardware, or even the human body inside it. All of this can be achieved by combining more than one materials; a hard material on the outside and the soft material on the inside

Hard Outer Layer for Penetrative Loads The materials needed for the exoskeleton’s outer layer should be hard and tactile. Titanium Alloy would be an ideal choice. Fiber glass has good tensile strength but not good shear strength, while titanium has both .Titanium Alloy is not only much stronger, but is also lighter than steel, which will provide more fluidity of movement compared to any heavy material counterparts.

Ductile Inner Layer for Shock Loads There should be a soft inner linings behind titanium panels to serve as shock absorbent. Sorbothane is a material that is extremely soft and has the ability to convert shock loads into heat transfer at a molecular level. It is a proprietary, visco-elastic polymer. Visco-elastic means that a material exhibits properties of both liquids (viscous solutions) and solids (elastic materials).

Sorbothane is a thermoset, polyether-based, polyurethane material. Sorbothane combines shock absorption, good memory, vibration isolation and vibration damping characteristics. In addition, Sorbothane is a very effective acoustic damper and absorber. Even if one drops an egg from the top of a building into a bed of sorbothane, this remarkable material is soft enough to cushion the impact and would not allow the egg to break.

This technique of having a hard material on the outside and the soft material on the inside is not new. It has been used for centuries in Japan for making samurai swords. The hardness of its outer layer give the swords its cutting edge and penetrative power, and its ductility allows it to absorb shock loads when it strikes or struck. 

2. ENERGY ANALYSIS : Hovering Capability

Hovering using thrusters (aka repulsors) requires tremendous amount of energy, particularly when the suit is used for a long duration. Energy usage for hovering is dependent upon the hovering methods

Magnetic Levitation requires no energy at all, but is limited to the presence of magnetic field.

Ducted and Open Propellers (helicopter blades). Several human powered helicopters have been made overtime that have achieved flight. It has been experimentally recorded that a 78 kg person in a 58 kg copter requires only 1.1 kW to climb using helicopter blades, and only 60 Watts to maintain altitude.

Jet Thrust is the least energy-efficient method. Because thrust-to-weight ratio needs to be greater than 1 to achieve lift-off, a Jet-pack requires over 1KN of thrust force, depending on the weight of the jet and the person. If wings are attached to the jet-pack, horizontal flight can be achieved with thrust to weight ratio lower than 1, thus improving the duration of the flight and its range.There have been jet-packs made in the past, most iconic display of it was in 1994 Olympics opening ceremony. The fuel used in the jet-pack was mostly hydrogen peroxide. It provides thrust at low temperature compared to other fuels. However, it has low energy density of 810 Wh/kg, giving the jet-packs up to only 30 seconds of flight-time. Jet’s flight time is limited even by using energy-rich fossil fuel. Yves Rossy (aka Jet Man) has successfully used kerosene oil in his flight, but the thruster jets have to be pushed away from the body for safety. His suit allows only several minutes of flight. In addition, if a heavier suit (greater than 25 kg) is used, hydraulics are needed, which would require additional energy and slow down mobility. The Iron Monger suit was an example of hydraulic-driven mobility suit.

3. POWER SOURCE

Tony Stark manages the suit’s energy requirements, including thermal management and artificial intelligence system, through the fictional arc reactor. The reactor is able to provides almost limitless clean energy despite being a very small device. In real life, the only thing that has an energy density comparable to the arc reactor, and would meet all the energy requirements of the suit would be nuclear power. Uranium (fission) energy density is 80.620.000 MJ/kg. However, nuclear power is not suitable to be harnessed in a manned suit, since it generates a tremendous amount of heat.

A more practical solution would be a battery energy-storage. If lithium batteries are used on propeller blades, minutes-long flight time can be achieved. Furthermore, these batteries can readily power suit’s electrical devices / electronics requirements. Lithium ion battery has energy density of 150 Wh/kg (0.5 MJ/kg). Fossil fuel, on the other hand, have a much higher energy density than batteries, but would require a clunky generator to power the suit’s electrical requirements.

Lithium sulfur batteries have 5 times more energy density compared to lithium ion batteries. Lithium sulfur packs had already powered the longest unmanned flight for more than 30 hours. Unless we discover something like an arc-reactor, lithium sulfur batteries could be just the thing to power up the suit. The downside is, it requires hours of charging for just minutes of usage.

There is an alternative option, though not a ‘reactor’ proper. A compact and high-output generator (standard car alternators crank out 50-70 amps at 12 volts for years, and some can go as high as 150 amps) could be spun by a small and strong output electric motor (all alternators have to do is spin). That motor can be powered by a high density battery like used for electric bikes in the 1500w to 2500w range at 20 something volts. This would power a strong and small motor at 3500 to 4000 rpm for hours. That’s more than enough to create power for a number of systems, if they’re built to take advantage of the amperage. And with new constructions of carbon arrays coming out every day, one or more of those could bring a meaningful electric output increase in an otherwise standard generator, even above what we have in cars now.

4. THERMAL MANAGEMENT 

The suit cannot be hermetically sealed. Human body heat evaporates water from the skin. Therefore, air ventilation is a must to remove them. It is also needed to maintain a good supply of oxygen. So, there must be a structure inside the exoskeleton that allows air flow. This would prevent any internal condensation to settle and will also remove buildup of body heat. The layer of sorbothene would act both as a thermal and an electrical insulator. This means that extreme external temperature would not be transferred to the inner layer. The suit would not get too hot or too cold from the outer environment. There should be small fans to draw and pull air from the ambient in controlled amount, and should be able to exchange hot air. With the technology available today, the thermal management of the suit is easily manageable. There are also solid state devices such as thermal pads and thermoelectric generators. Thermoelectric generators can surfaces hot or cold depending on the polarity of the electric current and thus can be an integral component of the suit for controlling the internal temperature.

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Adieu 2016 - Best of FYP!

2016 has been a great year for FYP!

And we would like to conclude it with some of the best posts that we have been able to produce

1. Black hole are not so black - series

Part - I , II, III

2.‘Katana’ - A sword that can slice a bullet

3. A denied stardom status - Jupiter

4. The Pythagoras Cup

5. On Pirates and Astronomers                                                           

6. Behold- The Space Shuttle Tile

7. Principle of Least Effort

8. Leidenfrost Effect

9. Major Types of Engines

10. A holy matrimony of Pascals and Sierpinski’s Triangle

11. Curves of constant width

12. Smooth Ride, Bumpy Road

Thank you so much following us ! Have a great weekend :D

 - Fuck Yeah Physics!

Fallstreak holes are natural phenomena that often get mistaken for UFOs. These ‘hole punch clouds’ occur when water droplets inside a cloud freeze and fall beneath it, creating a large gap that looks like a perfect hiding place for a flying saucer.

Aliens, obvi.

The rarity of fallstreak holes is what tends to throw people.

That paired with the tendency to look at anything in the sky and cry ‘UFO!’ is the perfect makings of a false alien alarm.

Sometimes these clouds have little rainbows inside.

They aren’t always circular, though…

They make all kinds of crazy shapes.

Including airplane/sword/cross/wieners.

Photos via: Rantplaces

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