Category: Chemistry

Airbags Do Not Have Air

By Anupum Pant

One important thing about the airbag is that it has to get deployed within milliseconds to save lives during an accident. A pellet of a very poisonous compound called Sodium Azide, or NaN3, does the trick.

The airbag system consists of a deceleration detecting device. Mostly this is a cylindrical tube with a metal ball inside whose movement is dampened by a spring or magnets. This prevents the ball from sliding the other side when the car goes on potholes etc. So, when the car hits something and stops suddenly, the ball goes to the other side of the cyllinder and completes the circuit.

Sodium azide decomposes at 300 degrees centigrade. The completed circuit supplies enough heat for sodium azide to burn/decompose and form the Nitrogen gas at a very rapid rate. The expanding Nitrogen gas blows out at about 200 miles per hour and inflates the bag within miliseconds.

The reaction also produces sodium which could cause a fire. So, we have two other compounds KNO3 and SiO2 with the sodium azide pellet. These are only to remove the dangerous sodium from inside the airbag.

Now, since the bag come out so fast and inflates into a rock hard balloon, it isn’t exactly soft enough for a face to hit it. So, after it is inflated, the bag is programmed to deflate a little. And it has to be quick enough to expand before the face even reaches it. Or the bag surface travelling towards you at a speed of ~200 miles per hour isn’t a good thing to hit when you have an other accident to deal with. That’s the reason sodium azide is used.

And that’s the reason an airbag does not have what its name says it has – air. It has Nitrogen. Which of course is almost air, because air is about 70% nitrogen. But it still isn’t the same thing.

Largest Molecule Synthesised

By Anupum Pant

Previously polystyrene was considered to be the largest single molecule that was synthesized artificially. A single molecule of it could weigh as much as 40 million hydrogen masses.

It was hard to make bigger molecules in the lab because they tend to break as you reach a certain limit.

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However, in 2011, Dieter Schlüter and his collegues at the Swiss Federal Institute of Technology in Zürich synthesized an artificial molecule that weighed as much as 200 million hydrogen atoms. It’s called the PG5. The molecule was so huge that it spanned 10 nanometres and had so many bonds that it could hide other substances (like drugs) inside of it.

It had to be done by taking a carbon backbone and adding other molecules and atoms to it. It took about 170,000 such new bonds to create this massive tree like molecule.

via [Scientific American]

Chasing, Avoiding, Attracting and Dancing Droplets

By Anupum Pant

These droplets intentionally coloured differently are different, not because of their colours, but because of different concentrations of propylene glycol and water. In this beautiful video coming from a team of researchers in Stanford demonstrates how a droplet with more propylene glycol seems to chase a droplet with more water etc. For instance, in the one where this chasing happens, which looks more like the droplets have brains of their own, the droplet with more water actually exerts a higher surface tension tug, pulling the propylene droplet along.

$761 Jar of Peanut Butter

If you have been active on the internet, there’s a great chance that you noticed this image of a peanut butter jar which had its price labelled as $761. That’s too expensive for a jar of peanut butter. Especially for a jar of it which has no added precious metal powder, or diamonds or anything else either. It is a standard ordinary form of the most popular american spread – the peanut butter.

If you are interested, you can buy it here on the National Institute of Standards and Technology’s website, as a standard material of reference. It’s up to you to decide because for 761 dollars you would only get around 500 grams of it. Or you probably can’t even buy it because it is meant as a standard material for scientists, governmental regulatory agencies and manufacturers around the world. According to NIST, it is perfectly homogeneous. That is to say that any part of it you take, you’d get the same composition.

This is one of the 1400 such items you can buy on that website. Others are lake Michigan fish tissue, spinach slurry, new york waterway sediment, SPAM (meat homogenate) and more… all of these for around 700 dollars or more.

More about it on [Smithsonian]

What do You Know About Lithium?

By Anupum Pant

You probably know that Lithium is the lightest metal, and the lightest solid element too. But I’m sure there’s a lot more about it you have never heard.

This chemical element with an atomic number of 3, despite how ordinary it seems, is one of the strangest elements in the periodic table, and the universe itself. It probably shouldn’t even exist on earth. Ben Lillie explains why…

In The Limelight

By Anupum Pant

If you are famous, you are “in the limelight”. There’s an interesting origin to this phrase which goes back to the theatres of 19th century.

During those times, the stage in a theatre was lit using all sorts of gas lamps. But the star of the show had to be in a sharp and focussed “limelight”. For that, well, lime was used. That is where the world limelight comes from.

Quicklime is Calcium oxide. Back in the day, in theatres, it was just another form of lighting. When it is heated at very high temperatures, at about 2400 degrees centigrade, it glows brightly. The mechanism isn’t very different from a usual bulb – which uses a filament of tungsten, heated using electricity (resistive heating). A different source of heat, hot enough to make lime glow, something like a blow torch was used. Lime was cheap, and unlike thorium oxide which could be used to do the same thing, it wasn’t radioactive. It didn’t wear easily and lasted for long times. Thus, limelight.

Rainfall Spews Aerosols

By Anupum Pant

Remember the time I mentioned petrichor? No one at that time was totally sure about what caused this. The constituents which made it up certainly were known, but the mechanism was hidden.

There’s a good chance that mechanism is no longer a mystery. A team of MIT researchers, using hi-speed cameras seemed to have found something which has never been directly observed till date. It’s amazing that rain falls all the time, everywhere, and so many people have access to hi-speed cameras, yet only the ones who are observant enough have first seen it.

When a raindrop falls on a porous surface, very tiny bubbles get trapped under it. Pretty soon, like the bubble rising from the bottom of your coke, these rise up to the surface of the bubble and escape. These escaping tiny bubbles spew a fizz of aerosols into the air – which probably is constituted of several compounds and gives the rainfall its signature smell. This could be the mechanism, or not. It’s a hypothesis for now.

What amazes me the most that no one thought of looking through a hi speed camera to see what causes petrichor. A simple thing to be discovered, yet a major discovery. I can’t think over enough, wondering how many simple things around us are happening every minute and are still waiting to get discovered.

via [MIT News]

Finding if There’s Juice Left in a Battery

By Anupum Pant

It’s hard to tell a dead battery from a good one. Or is it? Like you can find out if an egg is spoiled by dropping it in water, a bad battery can be spotted by simply dropping on a hard surface. If a battery bounces more and fails to stand up, it certainly is a bad one. But if it doesn’t bounce as much and stands up on the hard surface, if dropped from a small height, it is a good one. But how does this really work. Or does it?

Yes, it sure is a good test to find your bad alkaline batteries. According to a popular theory, this works because gas gets collected inside a battery which makes it pressurized, so it starts bouncing more as the juice goes out. This has been tested, and not found to be true.

Instead, what makes this work is pretty different from that theory. In a good battery, the inner part of it is very mushy – or, not firm. That is mostly due to the presence of Manganese dioxide, which is added to prevent the gas from collecting inside a battery. So, this mushy matter inside it contributes to an anti bounce mechanism.

As the juice gets used up, the manganese dioxide changes to a more firmer manganese oxide, and a relatively hard core is left inside a finished battery. So, when it is dropped, it bounces more than the battery that has mushy stuff inside it.

The following video tests it –

Electrons Faster than Light. No.

By Anupum Pant

The Rutherford-Bohr model or simply the Bohr model described the structure of an atom. In it, the nucleus consisted of protons and neutrons, and was positively charged due to the presence of protons in it. Electrons revolved around the nucleus in circular orbits. It was a very simplified description of an atom and served as a good introductory means to teach the structure of an atom. However, several decades back this model was superseded by the Shrodinger model of atom which described the structure of an atom using quantum theory.

The Bohr model fails on many levels – these have been listed here. [Link]

Richard Feynman, using the postulates of Bohr model, argued that the last possible element that could possibly exist would be the one with the atomic number 137. That is to say, no elements greater than atomic number 137 could exist. This argument comes from a simple analysis.

When you consider the Bohr model, and keep filling the nucleus with protons, a point reaches when the charge inside a nucleus becomes very high. In order to maintain a stable orbit around such a high atomic number element, the electrons in the lowest level (having the smallest radius of orbit) would have to move really fast. Or they’d simply crash into the nucleus. When the atomic number reaches more than 137, the calculations using the Bohr model tell you that the lowest electron (1s electron) in such an atom would have to revolve around the nucleus with a speed that would analytically end up being larger than the speed of light – which of course isn’t possible because nothing travels faster than light. So, the element 137 just cannot exist, or so argued Feynman.

Stainless Steel Soap

By Anupum Pant

How in the world would a piece of metal be used as soap. I never knew something like that could be used to clean your hands. But it does and there’s a fairly scientific hypothesis explaining why it works.

Stainless steel soaps are real and you can buy them in stores. These soaps apparently help to remove or neutralise strong odour from your hands after you cook – like the smell of garlic, fish or onions. Although not everyone agrees that there is a solid scientific explanation for it, but it does work and you can try it at home. Even if you prefer not buying a soap to test it out right away, you could use any stainless steel surface for it.

So, when you have strong odour on your hands after cutting, say onions or garlic, you could try rubbing your hand while the water is running, on a stainless steel sink’s surface, or any other utensil made out of that alloy. This is how it is believed stainless steel soaps work.

The sulphur from stuff that causes odour to stick to your skin can bind stronger to the stainless steel surface than your skin, or that is what they believe. So, when the sulphur goes away and binds to the stainless steel surface, the odour from your hand is gone.

The exact working of this is not known. But, catalytically induced oxidation of odor molecules and an absorption of molecules on the surface of the stainless steel (especially a chemical compounding with ferrous, manganese and/or molybdenum molecules).

Onions and garlic contain amino acid sulfoxides, which form sulfenic acids, which then form a volatile gas (propanethiol S-oxide), which forms sulfuric acid upon exposure to water. – About.com

Like we all know, using only water makes it worse. Why not try it out for once.

For hardcore scientists like Dr. Bob Wolke, a professor emeritus of chemistry, this doesn’t seem to work. Granted he didn’t conduct a perfect scientific study. Probably if he did, he might something. Well, it does work for people, if it works for you too, great. How does it matter.

via NPR

Wood Turned to Stone

By Anupum Pant

For a whole semester I had not noticed a huge 5500 pound log in front of one of the buildings at college which I used to pass by everyday. Probably because trees are everywhere and to prevent me from getting overwhelmed with excess information, my subconscious chose to filter it out. Today, while parking my bike I did chose to give it a conscious look. There was a board by the log which mentioned what it was and it was clearly something that was worth displaying.

petrified woodThis thing I was looking at was a petrified wood specimen. Yes, a piece of wood that turned into rock several million years ago. It was 220 million years old. Elated, I posted its picture on my instagram. This is what it looks like.

At first, not knowing how it must have formed, I thought it must be due to high pressures, like diamonds are formed. However after going through some text online I found out that the process by which these things are formed is very different from how gems like diamonds are formed.

Very specific conditions need to be met in order for a wood to turn into stone. It starts with a piece or a stump of dead tree getting engulfed with sediments or something else. This prevents it from coming in contact with the atmospheric oxygen. The cut off oxygen supply delays the decomposition of this log. So, now the log would take centuries before it is decomposed. It remains intact inside.

Now, if the wood comes in contact with mineral rich water or volcanic as (in ways that doesn’t burn the wood), the water starts soaking into it and starts replacing the organic matter with minerals. The whole log’s cell and fibre structure is preserved because all of this takes place at a microscopic scale. Over millions of years these minerals like silica crystallize and forms the petrified wood. The rate at which this whole process occurs is not very well known.

326346_1348795063If there’s just silica, they aren’t usually coloured. But if it gets infused with other element rich minerals like copper, cobalt, manganese etc, these woods can end up getting lined with beautiful colours. Other times silica can crystallize in different form an create an opal inside a wood. These make rare and beautiful gems like this one. [more pictures]

Due to the crystals that are formed in it, these usually break with clean cuts and give it an appearance like the wood stem was cut using a chainsaw.

Petrified wood is not too rare. Often, you can find them strewn over rock formations. I would very much like to stumble over one some time. I still consider it precious because it’s millions of years of history sealed in wood. But then that can be said about every stone you come across. This however is something that happens when very special conditions come together.

Sometimes whole forests get petrified and among these some trees can remain standing. In such cases a standing petrified stump is a beauty to watch. Here’s a 15 million year old standing petrified wood caught on video.

Researchers have made instant petrified wood in laboratories too. For this, a few material scientists from Pacific Northwest National Laboratory cut a cube of wood and gave it an acid and silica bath a couple of times, air dried it and then cooked it for 2 hours in an argon filled furnace at 1400 degrees Celsius. [Link]

Petrified wood is often cut into little pieces, polished and used in lapidary work, or to make jewellery. Tabletops are made out of slabs cut out of huge logs.

[Ref 1] [Ref 2] [Ref 3]

Making Caesium at Home

By Anupum Pant

Caesium is a soft, silvery-gold coloured alkali metal with a melting point of 28 °C. Like the other alkali metals, it reacts vigorously with water – it explodes when it is put in water. Even in air, it catches fire – due to a spontaneous reaction with the oxygen and water vapour in the air. To store it, an atmosphere of noble gas surrounding the metal has to be used. In all, it is a very interesting metal. And like always, interesting things come at a price.

Caesium is expensive. A gram of it costs about as much as the same weight of gold. So, Thunderf00t – a youtuber – who wanted to be able to go about watching it explode in water, or burn in air all the time, decided to make Caesium at home – using a soap dispenser and a barbecue grill.

Since Caesium boils at a relatively low temperature (of about 700 °C), in theory it can be distilled out when two relatively cheap reactants – Caesium chloride and Lithium – react. Here’s how it can practically be done at home. Amazing!

Seaborgium

By Anupum Pant

Until now I hadn’t even heard about an element called Seaborgium. That is because it is one of the most unstable elements which don’t usually exist naturally. Since it doesn’t last for too long, to study Seaborgium, it has to be artificially made (which itself is very difficult) and then studied in the laboratory very quickly before it goes away. Here’s is more about it, “periodic videos” explains.