science – Page 20 – Awesci

Deal with Poverty or Go to Mars?

by Anupum Pant

Indian Space Research Organization (ISRO) launched its Mars orbiter, Mangalyan (Translation: Mars Craft) on November 5^th 2013 with a hope to become the 4th such organization in the world, to step into Mars exploration. I must say, it is quite a fete for a developing country which has to deal with a myriad of other socio-economic menaces. Besides that, this mission also placed India above every other Mars mission ever, in terms of the total cost involved. Frugal engineering, has helped ISRO to go to Mars with low costs – with a mere $73 Million dollar budget, MOM (Mars Orbiter Mission) has become the cheapest mission ever to Mars. [silly comparisions to put this into perspective]

Side note: India’s other pioneering low cost endeavors – World’s cheapest car; World’s cheapest tablet and cheapest house.

But, this successful launch came with a throng of detractors, ridiculing India for not using these $73 Million to deal with poverty (or “clean feces off its roads”). Clearly, they did not think it through before making such comments.

A nation’s economy is a huge and complex thing. Things aren’t as simple as, stop space exploration funds and divert them to tackle poverty. A number of things run in parallel. Also, every nation has its own set of problems and they don’t stop spending billions of dollars for technological advancement to focus only on social or economic issues. And, I’m sure that the government India is also taking enough steps to tackle its national issues with a firm footing on advancement of technological avenues like space exploration.
The main part of this article: In contrary to what is popularly believed, money spent on space exploration does not nebulously float out of earth (on the other hand, distributing this money among the poor would breed complacency among them and cause the money to literally float out). It plays a major role in creating new technologies, products, jobs and businesses. Let us take the example of NASA here:
Space exploration has led to development of many things that you use daily. There wouldn’t have been any computers, wrist watches, Velcro, cell phones, GPS navigators etc, if funds were never allocated to the “wasteful” space research. Without this, there is a chance that you wouldn’t have heard of solar energy, cryogenics or even robotics. Also, several improvements in health care, energy and the environment are a result of research done for space exploration. [10 NASA inventions you use everyday].
When you think of all this, $73 Million seems like an extremely small number. Remember, that this is also helping other businesses (vendors etc) flourish, which in turn are creating jobs for the poor and spurring innovation.
Thirdly, The Indian Space Research Organization is a unique organization which has managed to stay the world’s most profitable space organization and has sustained on a minuscule budget of about $1 Billion. It relies on the Indian low-cost mantra to develop innovative technologies. As a result, this intelligent government venture has helped to create a profitable environment for space research. Hence, it isn’t a “wasteful” allocation of funds. Additionally, with its engineers living off a small salary ($20,000) as compared to American engineers ($100,000), we can definitely place our trust on an organization like ISRO – Like previous missions, they’ll make much more than $23 Million from this mission too. In other words, they’ll bring money in, not let it float out (better option for dealing with poverty, than just distributing it among the poor).

That said, 21 out of 51 missions to Mars have failed and it means that there is still a long way for this absurdly low-cost Indian mission [also a risky one] to be a completely successful one. So far, it is doing pretty good. We can only wait and see, what the end will be like.

The Standard World Map is Misleading

by Anupum Pant

Mercator’s projection

Most of us have this image of the world in our minds. This kind of a map, today printed in almost every textbook, known as the Mercator’s projection was first created to make work easy for navigators. Even Google Maps uses a Mercator-derived technique to project the world on a flat surface. But, Mercator’s projection has only deceived our idea of geographical area for all these years. For instance, it has led us into believing that Greenland covers an area which is almost equal to Africa (Also, have a look at the size of Antarctica there. Gosh!). The comparison of these two land masses actually looks like this.

According to this infographic, the actual size of Africa is larger than US, China, India, Mexico, Peru, France, Spain, Papua New Guinea, Sweden, Japan, Germany, Norway, Italy, New Zealand, the UK, Nepal, Bangladesh and Greece, all of them put together. In short, Africa is around 14 times larger than Greenland. Do not underestimate its area.

You can try playing with various combinations on this web app – map fight. Try these: Australia vs. Antarctica; US (contiguous) vs. Russia; and of course Greenland vs. Africa; they’ll leave you spellbound.

Why does this happen?

Since our planet is a sphere (an oblate ellipsoid really), to project it on a flat surface like paper, the actual shapes and sizes of landmasses have to be distorted to some extent. There is no way around it. Today, hundreds of different projection methods meant for various purposes are available, but none of them can exactly show the actual shapes & sizes of the landmasses. Some preserve the shape, some preserves the size, and others preserve direction…so on…

Mercator’s projection, the devious one discussed above, for example, uses a cylindrical projection. That means, it stretches the areas on a globe, which are nearer to the poles. Hence, the imprecise size of Greenland and Antarctica.

What is a perfect map, then?

Even after developing hundreds of projection method, we haven’t been able to spot the perfect method, nor will it happen in the future. But, to get the right sense of area, a projection method known as the Peters (also known as Gall-Peters projection) projection, is said to be the most accurate (in terms of area). It is also one of the most controversial maps.

Peter’s projection also has a huge fan following in spite of its terrible appearance.

Bonus Map Facts:

National Geographic started using the, good looking, Robinson projection from the year 1988, and used it for ten years, then, it moved to the Winkel-Tripel in 1998.
An ideal Mercator’s projection would have infinite height if it doesn’t truncate some area near the extreme poles.
Peters pointed that the Mercator’s projection made developing countries seem much smaller than they actually are. He said that these errors made the struggles of developing nations near the equator looks much smaller to the developed world.
XKCD published a comic on projections – “What your favorite map projection says about you.” 977. [see the explanation here]

Super-hydrophobic Surfaces are Unbelievable

by Anupum Pant

It is almost impossible to get a lotus leaf wet. If you try pouring water on it, you’ll see that it will form little beads of water and quickly roll out of the leaf. This happens because a lotus leaf is super-hydrophobic. Although, even your raincoat doesn’t get wet, it isn’t super-hydrophobic. Water sticks to on the surface of a raincoat. Super-hydrophobic surfaces don’t let water stick on it. But how do they manage to do that?

The science – Contact angle

Every time a liquid sits on the surface of a solid, the liquid drop forms an angle of contact as shown below. Things that don’t get wet have a contact angle greater than 90 degrees and the ones that get wet form an angle lesser than 90 degrees. The greatest angle is always less than 180 degrees. Theoretically, a perfect bead will form at that angle.

Super-hydrophobic surfaces are able to push this angle to as high as 175 degreesto form almost a perfectly spherical water droplet on the surface (due to very high surface energy). This ensures that as soon as water falls on it, it rolls away. The surface never gets wet.

Advantages

Imagine things never getting wet. How about a completely water resistant phone, a shoe that never gets dirty, shirts that repel ice-cream and wind-screens rolling away rain droplets like magic? All these things are possible, if they can be converted into super-hydrophobic surfaces. [They can be. Watch the video below]

Besides repelling water, these surfaces can also prevent formation of ice, resist corrosion and prevent bacteria from sticking to it. The possibilities are endless.

How to do it artificially?

Today, we have managed to develop several artificial methods to make almost any surface super-hydrophobic. Commercial services like NeverWet, HydroBead and Lotus leaf coatings are making a roar in the market by offering amazing promises. Normally, they use simplified spray coatings to convert normal surfaces to super-hydrophobic surfaces, so any one can use them, anywhere.

Things You Should Know About Farts

by Anupum Pant

Flatulence, an expulsion of intestinal gas, commonly known as fart, is something no one likes to talk about because it is considered a taboo, almost everywhere in the world. To top it all, some might even sideline this article by tagging it as a vulgar one. In my defense, that is exactly the purpose of my blog – To talk about things no one will talk to you at school (or anywhere else). Our inclination here is to learn.

Avoid shaming others for it.
Firstly, it is important to know that, irrespective or gender, race or nationality, farting is an invariable result of digestion and everyone does it about ten times a day. Even dead people fart. So, by shaming someone for letting it out in an accidentally loud way, is hypocritical on your part; it [shaming others] can be avoided. As Eric Auld says, it is okay to fart.

Do not hold it.
Secondly, it is not okay to hold flatulence to avoid embarrassment. Doing this, has the potential to cause a life threatening condition called diverticulitis. This disease is prevalent among the urban people for obvious reasons. Urban people have a greater societal pressure to hold it, than a free-living farmer. To give you an idea, 30 million Americans are currently suffering from it (old data).

What is it?

Principally, it is a mixture of gases taken in through mouth with food and gases which are produced while digesting food. The composition of ‘gas’ varies with, people, the kind of bacteria in their stomach and the kinds of food they eat. Oftentimes, people don’t hate their own smell; at the same time, detest the gases coming out from others. A fart is comprised of gases like Hydrogen, Nitrogen, Carbon dioxide, Oxygen and Methane. It smells bad due to the presence of Hydrogen Sulfide, Mercaptans and Ammonia. And the presence of inflammable gases like Hydrogen and Methane makes them inflammable.

Farts in a humid environment can seem worse because during such conditions, our sense of smell is enhanced. This is the reason why farts smell worse in a shower.

Minimizing the effect

Although, there is no way you can end this trouble from your life, you can adjust your diet a bit to prevent this from happening in excess. Beans, cauliflower, corn, eggs etc are some foods which are notorious for producing gas in your body. These foods release a relatively greater amount of gas than other foods while getting digested in the intestines. Cutting their intake can help (of course consult your doctor first).

Another way to lower the problem is to prevent the odor from troubling others. This can be done by using products like “odor-proof undies”.

Coughing or suddenly moving your chair could help you to mask the sound.

A Bat’s Inverted Sleep Position

by Anupum Pant

I have written about sloths in the past. In that post, we appreciated the way their bodies are engineered to stay inverted for most of their lives. It turns out, a bat’s body is designed (rather evolved) in a similar way, which enables them to relax and sleep upside down. In this post, I would like to discuss – why did they evolve this way and how do they do it?

If you are interested to know more about bats, you will definitely like this post from the archives. [Bats can See]

How can bats manage to sleep like this?

Humans sleep in a horizontal position, cows sleep with their eyes open, horses sleep in a standing position, and of course, bats sleep in an inverted position. What makes an animal sleep in the position they do, is basically their anatomy – the way their bodies are designed. While sleeping upside down might seem as an anomalous behavior to us, it is a normal position for the bat’s body. Like we don’t exert energy when we are lying down, bats’ bodies don’t consume extra energy for hanging down like that.

Firstly, a bat’s claw is like a hook. A better way to understand why this helps is, to look at a converse behavior – the way a human hand works. We use up energy to contract tens of muscles and make up a hook with our fingers; this is not a normal state of our hand. Also, our relaxed hands are open where we don’t exert any energy and we sleep with our hands in that position. A bat’s claws are designed in a completely inverse fashion; they are hooked in the normal position. They don’t take up energy to make them into hooks, they are like that. And they sleep like that – which enables them to hang without using energy.
So, unlike our hands, a bats’ closed fist is their relaxed position. They have to contract tendons and use energy to open them up. This anomalous talon design allows them to hang in a relaxed position.

Secondly, unlike every other bird, a bat can’t take off from an upright position, or from the ground. They have to be inverted to start flying. This is because they have relatively weaker wings which can’t make them fly from a stationary position. Think of an X-51A Waverider, which has to be carried on a B-52 plane and dropped down to start a flight. They drop down for a very small amount of time and beat their wings vigorously to start a flight. Since, they have to wake up inverted to go flying and catch a meal, they go to sleep like that.

Why did they evolve this way?

They’ve evolved this way to simply stay away from the predators:

By hiding up in a place where not many predators would look – under a bridge, roof of the cave and dark tree canopies. Also, at places like these, they don’t have to compete with other birds for a place.
And by escaping quickly in case of an attack by attaining instant flight [see above].

That Sweet Scent of Rain

by Anupum Pant

When rain starts falling after a long dry spell, most of us notice a sweet-musky scent around us. Sometimes, it is as if you can smell the rain coming. Have you ever wondered what causes this peculiar smell?

Well, scientists have also wondered the same for a long time and now they have some concrete answers for us. According to them, this evocative scent is a mixture of several individual smells. In essence, there are three factors which combine to form the “petrichor” – The smell of rain.

Bacteria – The best (my favorite) of all the three is caused because of a specific type of bacteria in mud called Actinomycetes. The force, with which the rain water falls, disrupts the bacteria-produced-spores in dry mud, and the moisture present in the air carries them to our noses. Most people love this odor and associate it with rain.
So, spores of bacteria are responsible for the kind of smell you get, when rain falls on dry mud.
Plant Oils – A blend of oils produced by plants during the dry spell is another main source of this aroma. When it rains, volatile parts of these oils get released into the air. It is the kind of smell you get when you are getting wet in the woods.
Ozone – Another smell associated with the rain, is a minor part of petrichor and it smells like burning wires. This is produced by a reaction caused when lightning strikes, the Nitrogen and Oxygen present in air to form Ozone molecules.

Subjective senses

Besides that, smell is a subjective sensation. That means, you can’t explain a smell to someone, and you can never know what the other person smells. So, it becomes really hard for scientists to communicate to us, which scent is which.

Some of us like the bacteria smell, while others might like the third component of petrichor.

Some like the smell of rain, others don’t. But we’ll never know accurately, if the scent you adore is the same as the one your friend hates. One way to communicate some information about these scents is by comparing them with other popular smells (like I did above). This could probably give you a vague idea, but the exact sensation will remain elusive. It is like trying to explain the color red to a person who’s been blind all his/her life.

Bats Can See

by Anupum Pant

While every teacher around the world is busy teaching their kids that bats are blind, the contrary is actually true. Bats aren’t really blind and they can see pretty darn well even in low light. In fact, their eyes work better than our eyes do in a dimly lit environment (eg. Moon light).

None of the bats’ 1100 species are completely blind. Although, there are a few which depend heavily on a technique called echolocation to navigate around objects which are near, they still have to use eyes to see objects which are far away. Additionally, most bats like to hunt in complete darkness (to avoid competition from other birds), so they use echolocation during such times [because eyes need at least some amount of light to be present]. The daylight hours spent by them to groom or sleep don’t demand much of their visual skills, but that doesn’t make them blind.

One way in which bat’s vision is poorer than our visual ability, is that they can’t see colors like we do. Everything they see is in black and white. This disability, if you may call it one, is compensated by their ability to detect light waves whose frequencies lie beyond the human visible spectrum. Flying foxes, however, which are actually bigger bats, can see colors.

So, simply put, bats can see, but they don’t have to use their eyes to hunt or move around. This makes your teacher wrong when he/she says chides you with the phrase – “Blind as a bat”

Bonus Bat Facts

Bats don’t carry rabies. However, like humans, the disease affects some bats.
Apart from vampire bats found in Mexico, Central America and South America, no other bats suck blood.
Bats hunt insects above your head, they aren’t interested in your hair or your eyes.
Bats can catch insects with their tail or wing membranes.
Fruit bats are also known as flying foxes, they eat fruits.
Bats collectively eat tonnes of insects and protect our crops.
Some bats eat fish and frogs.
Bats’ dung, is rich in nutrients. It is mined from caves, bagged, and used by farmers to fertilize their crops.

Echolocation: A bat echolocates by sending out streams of high-pitched sounds through its mouth or nose. These signals then bounce off nearby objects and send back echoes. By “reading” these echoes with its super-sensitive ears, the bat can determine the location, distance, size, texture and shape of an object in its environment. In some cases, a bat can even use echoes to tell insects that are edible apart from those that aren’t. – [Source]

Horror Movies are Good for You

by Anupum Pant

It is Halloween today and most of us must be busy making plans for the day. But if you’ve missed including a horror movie in your plans, after reading this post, you might want to consider putting it in the list.

Studies have shown that watching a horror movie can actually be beneficial to your health. In two separate experiments, scientists were able to record two different ways in which horror movies can be good for you. Of course, this shouldn’t encourage extremely sensitive people to force horror movies onto themselves. In spite of these proven benefits, pregnant women, old men, little kids and people with heart disorders must try to stay away.

Moreover, the benefits found, were not practically too big. So, if you are thinking of leaving your healthy diet plan and making up for it by starting to watch more horror movies, you are mistaken. But, scientifically, the discovery of such co-relations are considered as noteworthy.

The first study (increase in immunity)

Researchers suggest that while people watch horror movies, their brain secretes chemicals like dopamine, glutamate and serotonin. As a result, there is an increased brain activity, which makes the mind alert for a while. Additionally, threat signals that pass through the brain stimulate adrenal glands to produce adrenaline, which has an anesthesia like effect.

Secondly, a half-hour watch was found enough to boost the number of active white blood cells in their blood – they are responsible to keep diseases away. In the test, a first time watch of Texas Chainsaw Massacre by 32 men and women led to an increased immunity for some time. [Source Paper]

The second study (burns calories)

In another study conducted recently, scientists observed an average of 184 burnt calories among the people who watched The Shining (the 1980 thriller). Jaws took the second spot, with people burning on an average of 161 calories after watching it, and The Exorcist came third, with 158 calories. Top 5 calorie burning movies were as follows:

1. The Shining: 184 calories
2. Jaws: 161 calories
3. The Exorcist: 158 calories
4. Alien: 152 calories
5. Saw: 133 calories

Increased heart rate, muscular contractions, a surge in adrenalin, oxygen intake and greater carbon-dioxide output were the main reasons that these extra calories got burnt. So, the next time you are watching a horror movie (working out), avoid popping popcorn. [Read more]

The Sun’s Unusual Behavior – Seen from Mercury

by Anupum Pant

The sun – as seen from Earth

For most of us living on Earth (closer to the equator), the sun has followed a simple path throughout the years. It rises, goes up at noon and then sets for rest of the day. It is a simple straight line for the complete year.
For people living a little away from the equator, things get a bit interesting. There, the summer sun at noon is overhead, but the winter sun is low at noon, not overhead. It isn’t very easy for a person living near the equator to grasp this phenomenon well. You’ll have to go there and see for yourself. Or simply, the simulator at the end of this paragraph will help you understand it better.
At poles, the sun almost moves horizontally for many days. It keeps on making a horizontal circle around you. There, it is day for 6 months and night for the next 6 months. [Here is a sun path simulator for Earth]

However, nowhere on earth, things get as interesting as they get in the skies of Mercury.

The sun – as seen from Mercury

On Mercury, the sun appears to briefly reverse its usual east to west motion once every Mercurian year. The effect is visible from any place on Mercury, but there are certain places on its surface, where an observer would be able to see the Sun rise about halfway, reverse and set, and then rise again, all within the same day. It is indeed an unusual performance which isn’t easy for us Earthlings to digest. [See animation in the next paragraph]

Why does it happen?

Let us consider a simpler analogy – some planets (like Mars), as seen from earth, take a similar path. [see the animation for Mars’s path as seen from earth]

The planets, including Earth, all travel around the Sun in a continuous orbit. We can see them make their way across the sky in a straight line usually. However, every now and then a planet appears to turn around. After turning around, it appears to move back the way it came. This is called a retrograde orbit and is caused due to the difference in speeds at which the planets circle the Sun.

So, as we see Mars do a reverse from earth, a similar motion of sun is observed from the surface of Mercury.

[Apparent Retrograde Motion – Wikipedia]

Why is a Metal Plate “Colder” Than a Plastic Plate?

by Anupum Pant

No, it isn’t!

What is Cold?

According to the dictionary, a body at a relatively lower temperature, especially when it is compared to the temperature of a human body is described as a colder one. So, any object below the normal human body temperature – about 37 degrees Celsius – is a cold thing. But wait a minute!

When you touch an object, what does it tell you about the temperature of the object? Can you really judge if it is a cold one or a hot one? Unfortunately, our bodies aren’t thermometers, we are not so smart when it comes to judging the temperature. Consider the following case.

A book and a steel plate kept in the same environment for a long time attain the same temperature eventually (it is called thermal equilibrium). This can be checked by using a thermometer on both the objects. But, when people are asked to touch a metal plate and a book, they find the former to be much cooler. You can try this out yourself by touching different materials around you. You’ll see how some things ‘feel colder’ while the others feel warmer. A YouTube channel Vertasium conducted a social experiment to record this on camera. See the video below:

There is no cold – only heat

So, in the video, ice melts faster, if kept on steel plate than on a plastic plate, even when the steel plate ‘feels colder’. Common sense dictates that the colder thing is supposed to sustain the ice block for a longer time, just like your refrigerator does. So why does the opposite happen?

A better way to understand this ‘contradiction’ (not really a contradiction) can be this:

According to thermodynamics, simply put, everything has heat in it. So, even a cold ice block has some amount of heat stored in it (say, around 273.15 Kelvin or 0 degree Celsius). When one object comes in contact with other object, it loses or gains heat till their temperatures get equal or till they attain ‘thermal equilibrium’. Which object loses heat and which one gains it, is decided by their relative temperatures. In case of ice and steel, ice has a lower temperature than steel (assuming it isn’t already freezing out there). Therefore, here, ice gains heat from steel till they attain the same temperature and ice melts.

Side note: The ice is also in contact with a relatively ‘hotter’ atmosphere. Hence, it gains heat from there also. In this case, we are only concerned about the steel and ice interaction.

Why does it melt faster on steel?

There is a particular property which depends on the kind of material and is called thermal conductivity. This is the parameter which decides which objects lose heat quicker and which ones do it slower.

Here, for instance, steel has a higher thermal conductivity than plastic. Hence, the steel plate gives away heat to the ice block faster than a plastic block does. As a result, ice melts faster on a steel plate than on a plastic one.

Incidentally, this effect can also be used to explain why one plate feels colder than the other, in our hands. Think of it like this, the ice is replaced by our hand. So, a steel plate, due to its better thermal conductivity, draws heat faster from our hand than a plastic plate. This makes us feel that the steel plate is colder than the plastic one.

As checked by a thermometer, both the plates have the same temperature, our bodies are only fooled into believing that the thing we feel is temperature; it isn’t. None of the plates is actually colder than the other (according to the dictionary – see first paragraph). We don’t feel the temperature. What we feel is actually the rate of heat being drawn away from our hand. Faster an object draws heat, the colder it feels.

Understanding the Impending Helium Crisis

by Anupum Pant

There is too much Helium?

Helium is the second most abundant element in the observable universe, present at about 24% of the total elemental mass. Helium is also the second lightest element. So, 24% by mass is too huge a mass for a single light element. It equates to a measure that is probably millions of times more than what humanity could use up in millions of years. Close to about 12 times the mass of all the heavier elements combined, this element will almost never run out. But, that is only when we talk about the universe. Back in Earth, it is completely a different story.

Helium sources for us

On Earth, Helium is relatively rare. It amounts to only a 0.00052% volume of the earth’s atmosphere. Although 0.00052% is not too less, you also can’t consider it as an abundant element. Moreover, extracting Helium from air is almost 10,000 times more costly than fractional distillation (mentioned in the next paragraph). So, all that Helium in air is nearly useless to us till better methods of extraction are invented.
Thankfully, Helium is also present under the surface of the earth. The source of this kind of deposit is, radioactive decays which take place down there. It mixes with the natural gas and is lost to space, if released into the atmosphere. It is separated from natural gas using a process called fractional distillation – The best process to make Helium.

The largest known underground reserve estimated to contain about 10 billion cubic feet of Helium is a federal reserve (mostly under Texas and Kansas). For years US reserves had been the largest global suppliers of Helium (90%). Even today, these reserves contribute to more than 35% of the total global supply. The price of Helium coming from this source has remained almost unchanged for a long time. While during the same period (10 years) privately held Helium prices have tripled. The gap in prices is increasing every day, creating a big distortion in the market.

Helium Usage

Uses of Helium range from manufacturing smart phone screens (all LCD screens) to optical fibers (Internet cables) to health care (MRI scanners) to scientific research etc. [Uses of Helium]

The Problem

Since Helium has been made artificially cheap due to the Helium privatization act, it is popularly believed to be a cheap gas and is wasted a lot. Instead of using it up for important things, we consume it by filling up party balloons, distort voices and other entertaining activities. In fact, the warning issued by the Nobel Prize winner Robert Richardson that Helium could be depleted within a generation, seems to have had no effect on us. We still continue to waste a lot of Helium, release it into the air and keep losing it forever. Not many realize that it is a non-renewable resource.

We have almost reached a crisis already, but it was temporarily averted by the congress. In the future, after about 6-7 years, when the Federal Reserve stops supplying it (at below-market prices), it could be a big problem. I’m not very optimistic about market adjusting within such a small span either. In under a decade, we’ll probably see smart-phone prices, optical fiber prices and health care (MRI scans etc.) prices shoot up precipitously due to this artificial market distortion, if we do not start using Helium properly.

Plasma Speakers

by Anupum Pant

Not many would have heard of speakers other than those which use magnetic materials to produce sound. But if you still haven’t heard about Plasma speakers or ionic plasma tweeters, you are really missing something great. Read on for more.

About Plasma Speakers

I talked about sound a few days back and mentioned that it is something that propagates through a medium due to pressure changes. Normally, magnetic speakers create these pressure waves by moving a diaphragm with the help of a varying magnetic field. But, plasma speakers do this by varying the air pressure through a high energy electric arc. This arc is produced by ionizing the gas present in between two terminals (ionizing reduces the electrical resistance of air which creates a visible arc).

These speakers use an extremely high energy arc which also increases the temperature of surrounding volume of gas to very high levels. So, before learning anything about them, the first thing you have to know is that these seemingly harmless things can kill you.

The Dangers

Plasma speakers are not toys. Old men, people with heart problems, kids etc should stay away from them. Even if an adult is handling them, they need to be informed about what they are doing first. It is better to have someone close who knows well, how these things work. Although the commercially available speakers are fairly safe, DIY kits can prove to be fatal. The kind of dangers involved with these devices:

1. The electric discharge – Think of it as a lightning. The dangerous high voltage device has the potential to kill you, if any of your body part comes close. Keep all bodily parts away.

2. Gas danger – The constant supply of ozone used for this project can actually be much more dangerous than the electric arc. Ozone used in this project, silently increases in concentration which can be fatal. It is important to keep the room well ventilated.

A few more things about them

Invented by WIlliam Duddells in the year 1900 these are not speakers, but tweeters. That means, that there will be no window cracking bass that is going to come out of them. Unlike magnetic diaphragms, the arcs have no weight and are able to produce a very crystal clear sound by moving back and forth very quickly. See the video below.

They work by changing temperature inside the gas chamber which makes them go red to purple as the frequencies of a song change. However, an un-modulated arc will just produce noise, something like you hear at first in the video. Also, they need a constant supply of Helium and Ozone coming into the chamber. These gases get ionized inside to produce the arc.

[Read this for more history]

Where can I get them?

In 1970 Magnat used to produce them, but they no longer produce plasma speakers now. The point is, they were the pioneers in bringing this to the masses.
Acapella sells them for an eye-popping price of 23000$. These costly ones are revered for their sound quality.
Other DIY kit can be bought for as low as 100$ [here]
Build one on your own for cheaper. (if you are willing to risk your life) [tutorial here]

Harnessing The Power of Nature – Biological Data Storage

by Anupum Pant

The present storage technology

Storage technology has come long way from the year 1956 when IBM, the massive corporation started pushing this technology. Its journey started with data storage densities of orders as low as 40 bits per square inch in 1956 (RAMAC 350). This effort from their side indeed brought in great results and IBM could set a record of density record of 14.3 billion bits per inch, by the year 2000.

Today, in the year 2013, most HDDs (Hard Disks Drives) are able to store with densities of around 500 Billion bits per square inch; technology at this level has brought Terabyte sized HDDs to our computers. The research being done on increasing density of data is still a bustling area. As a result, we often see news breaking in with breath-taking new storage technologies almost every month.

Latest Stories

Just a few months back, using a technique called nanopatterning a team from Singapore was able to show 3300 billion bits per square inch. That is almost 6 times the density of a normal HDD. It means that a 1TB HDD of present size could hold 6TB if this could come to manufacturing units.

Seagate, in another story, promised data densities of the order 1TB per square inch (8000 billion bits per square inch) within the next decade. Which would enable hard drives of up to 60 TB in capacity.

A similar thing has happened to compact disks. From CDs to DVDs to Dual Layer DVDs to BluRays and several other storages that didn’t last – from zip drives to holographic storage. The data storage densities have improved dramatically.

Is it enough?

Although, our present ability to store a lot of data in small physical spaces is enough for now, to meet the future demands we will need to keep progressing with an unbelievable rate. The fact – physical storage is reaching its limit gradually, could bottleneck our progress in the future.

Biological Storage Devices

The exact storage concept used in amazing natural systems like the human brain and DNA has remained elusive for decades now. To keep up with the rapid pace of development it is important that we step up our work in this area. I think, the answer to our demands lies with the nature.

A brain, for instance, is estimated to be able to store something closer to 2.5 petabytes (or a million gigabytes). The sad part, we don’t exactly know how it stores. Moreover, we don’t even know how we could precisely calculate their storage limits. These estimates are just a theoretical calculation. We still have a long way to go.

The greatest storage device

Recent successful experiments with storage and retrieval of data in the human DNA has come with a new hope for the future. Teams at the EU Bioinformatics Institute and Harvard University have successfully stored famous speeches, photos, and entire books, and then retrieved them with 99.99% accuracy.

Being able to store data in the DNA will confer upon us three advantages. Firstly, it will be fast (very), yes, faster than the flash drive. Secondly, it won’t age with repeated storage cycles (around 10,000 years), at least not like HDDs which have moving parts. Finally, DNA will enable us to reach data densities of unimaginable levels. Imagine being able to store of half a million DVD disks in a single gram of DNA! Technically that would amount to 700 terabits per gram (measuring in area is difficult for an entity like this). Others have reached to densities as much as 2.2 petabytes per gram.

Bring DNA drives to our PCs I say!

A Few Things About Sloths Everybody Should Know

by Anupum Pant

A few days back, on 20th October, Sloth Day was celebrated all around the world. You’d be thinking, what is so good about these strange animals, that makes people have a special day around them. Well, in that case, you need to read this.

What are these creatures?

Sloths are slow animals that make even cows look extremely active. They are so slow that they are almost stationary and algae grows on their hair. Most of their life is spent on trees hanging upside down. They hang on trees to protect themselves from the predators on the ground. Their bodies are so well engineered to stay inverted that the hair on their bodies, is oriented in the opposite direction – growing from stomach to back (This helps them to stay dry by draining water easily). Even dead sloths have been know to retain their grip and remain suspended after death. They come down only around once a week to excrete. They eat, sleep, travel, find partners, mate, give birth and even raise young ones in the canopies.

Although sloths might seem gross, creepy and unseemly, they really aren’t that bad. Sloths are sweet looking [1] [2] [3] animals (especially their babies, they are adorable) who can also swim efficiently and move wisely. We can definitely learn a lot from them.

Their diet is unbelievable

Sloths eat only leaves throughout their lives. They chew leaves slowly like cows to extract whatever nutrients they can. Sloth intestines are also adapted to extract the maximum out of their poor quality food, they are unusually long. They often like to shift to a different kind of leaf after a day or two. This balances their nutrient intake. Humans couldn’t possibly survive on a leafy salad diet for a very long time.

To save energy, sloths drop the temperature of their bodies at night. Even their bodies have more bones than muscles to prevent wastage of energy through muscular movement. After the Orangutan they are the most energy efficient animals.

Other facts about them

Sloths have blunt teeth to chew leaves properly, have large claws to hang on to branches and inverted fur orientation (as also mentioned before). Another interesting thing about them is that they have remained physically un-evolved for a long time because they don’t really have to compete with anyone else for their diet.

Mutualisms

This is where the awesomeness of Sloths come in. Sloths are home to a several kinds of other organism (tiny ones living in their fur). These organism depend on sloths (hosts) for various things and in turn provide an advantage to their hosts. This is called mutualism.

Algae + Sloth – Algae, for instance, uses the long grooves on sloth hair to grow with a secure footing. As a rent for this safe apartment, the algae gives them [sloths] a nice shade of green color to camouflage on trees. This and their still bodies make them virtually impossible to spot with the naked eye. The camouflage protects them from eagles.
Bacteria + Sloth – Apart from the several other bacteria which live inside a sloth to digest the leafy diet, two kinds of Cyanobacteria live on sloth furs too. These bacteria also give sloths a nice gray hue which helps them in the same ways as above.
The Sloth Moth – The Pyralidae Moth also live on Sloths. These feed on the algae which grows on the fur. In return for the good food, moths give them nothing. Yes, nothing. This is called Commensalism.
Others – Similarly, various other organisms like flies, mites and three types of beetles are often found living in a Sloth. Up to 900 beetles have been found on a single Sloth!

There is so much more to write about these amazing little creatures who provide for so many other creatures too. I’ll keep it for the second part that I’ll write some other day. So the next time you see a Sloth crossing the road, carefully pick it up by holding its mid body and gently place it on a tree. Remember to use a glove/cloth.

Bricks Which Are Lighter Than Air

by Anupum Pant

What would smoke look and feel like, if you could solidify it?

Aerogels

Although, first made in 1931, Aerogels are relatively newer materials and a tremendous amount of research is being done on them everyday. Lightest solids ever, Aerogels weighing about seven times lesser than air have been made. Their extreme properties have given a fascinating field of interest to students and scientists. [Read the last paragraph]

How are they made?
Aerogels, also known as solid smoke or frozen smoke are extremely light materials. They are made by a process called sol-gel process which involves removing all the moisture from a specially made gel (Hypercritical Drying). Although the procedure may sound simple, there is a lot of technology involved in making them. Moreover, practically usable Aerogels which can endure moist conditions and high stress conditions are much more challenging to make. Also, it is very expensive to make them. [They can be made at home – with costly equipment of course]

Why is it so light?
The whole lot of porosity left inside due to drying of the gel is what makes it so light. You can think of them as a sponge which is hard like pumice. But, when you think of a sponge, remember that mostly Aerogels aren’t very resilient. That means, unlike sponge they won’t get back into the previous shape after they’ve been pressed a lot. They are much sturdier/tighter than sponges. A small (not very small; due to very low density they occupy large space) piece of Aerogel weighing just 2 grams has been shown to hold a 2.5 kg brick without deforming. Poorly made Aerogels, on the other hand can also not be very sturdy. They would deform with a hard press of a finger and stay deformed.

How light are they?
Agreed, they can be lighter than air, but the practical mass varies greatly. And they don’t float in air because, with air present inside them, they are slightly heavier than air (weight of air inside + solid material), but can be made to float in air by replacing the air inside it with Hydrogen ~~or Helium~~. Their lightness and density is completely dependent on the amount of porosity included during the fabrication – which can be controlled. Also, the kind of gel used to make it, affects the weight of the final block. So a block with 3 feet in length, breath and height can weigh anything from 1 kg to just 160 gm.

Aerographite, a carbon Aerogel made by German material scientists from Kiel University and the Hamburg University of Technology, was said to have weighed only 0.2 mg per cubic centimeter. It was 5000 times less dense than water and 6 times lighter than air (counting only the solid material’s weight of course). [Published Paper]

Graphene Aerogel: As if that wasn’t enough, recently, Chinese material scientists developed a lighter material than Aerographite. It was based on Graphene. A Graphene Aerogel; seven times lighter than air. This one, unlike other silica Aerogels, can recover like a sponge after getting deformed. [Published Paper]

Other Properties

Aerogels exhibit various other desirable properties which make them useful for a myriad of applications [See the Wikipedia Article]. For instance, they are very good insulators of heat. A nicely made Aerogel block which is just under a centimeter thick can protect things from a direct flame. Other desirable properties are high surface area, high thermal and acoustic resistivity, low dielectric constant, and low refractive index.

Aerogels absorb water or moisture from the air and even from human skin easily. Handling them with bare hands can cause blisters. But, the ones which repel water have been made successfully by altering fabrication parameters. Also, if particles of it are inhaled, it can cause problems. Hence, hand gloves and respiratory masks are used to handle them.

I want to study interesting materials like these

If you think Aerogels and Wolverine’s claws are interesting things. You can make a career in researching materials like these by making a foray into Materials Science and Engineering. Most good universities offer a course in it. It is a budding field, growing at a rapid pace with loads of opportunities waiting for you.