Tag: chemistry

Screaming Coin and a Singing Spoon

By Anupum Pant

Dry ice, or Cardice – as British researchers call it, is a solid form of carbon dioxide. When carbon dioxide is cooled below temperatures of -78.5 degrees centigrade, the gas gets directly frozen into a solid form. -78.5 degrees centigrade is extremely cold, and handling dry ice without proper protection can be very dangerous – could cause frostbite / burns. The point being, it’s extremely cold.

Since it’s too cold compared to something at room temperature, even everyday objects at room temperature can make it vaporize. A simple metal coin at room temperature would feel like a hot pan to dry ice. So, when a coin is shoved into a piece of dry ice, it creates a funny sound, just like water would, on a very hot pan; or, you could say the sound be very much like a hot metal ball being dropped into a cold bath of water (the temperature difference being much less in this case, of course).

This is how it works: The metal piece at room temperature vaporizes some amount of carbon dioxide from the piece of dry ice when it comes in contact. There’s a pressure difference (Bernoulli’s principle) associated with this process and the gas tries to escape. This makes the metal vibrate very fast, creating that funny sound. This is how it sounds…

Metals work best because they have a good thermal conductivity. For the sake of trying it out yourself, if you have a piece of dry ice lying unused, you could dip a spoon in hot water and make it touch the piece of dry ice. A slightly warmer spoon will probably give you a better effect. And then the spoon will be singing…

Nanokids and Nanoprofessionals

By Anupum Pant

In the year 2003, a group of researchers headed by James Tour at Rice university designed and synthesized a series of organic molecules that they thought would get kids interested in chemistry.

These organic molecules resembled human figures and were named Nanoputians – A portmanteau of nanometer (a unit of length used to measure extremely tiny distances) and Lilliputian (the tiny human-like fictional characters from Gulliver’s travels).

The synthesized nanokid molecule basically consisted of two benzene rings and a couple of carbon atoms for its body. For the limbs  acetylene units ending in an alkyl group were used. The upper body and the lower part were both created separately, and were joined using Palladium and Copper compounds. Here’s how…

nanokid body parts

The head of a basic Nanoputian was a 1,3-dioxolane ring. However, after using an advanced microwave irradiation technique, the team created a couple of other variants (called Nanoprofessionals) to replace the Nanokid’s head. Here is what the series of head variants that were created. As if that wasn’t enough, there is a nano ballet dancer too.

nanokids and nanoprofessionals

Now, in the scientific community, James and his team are better known for synthesizing a much more cooler thing – A nanocar. The nanocar they synthesized was a single molecule car which could be pushed around using a scanning tunnelling microscope. And another one which is fuelled by light!

There are a couple of other cool molecular machines they’ve made too.

via [FutilityCloset]

The Landolt Clock Reaction

By Anupum Pant

Steve Spangler Never ceases to amaze me. Once again I found this old video of him on the Ellen show. These are a few experiments he does on the stage…

  • Lights a tube light with his bare hands and Ellen’s.
  • A transparent liquid suddenly instantly changes colour.
  • Blows the hydrogen and oxygen mixture on Ellen’s hand.
  • And makes someone from the audience walk across the table on a non newtonian fluid.

Steve doesn’t exactly explains what happens there, but the second experiment is my favourite. It is the one in which he asks Ellen to pour two transparent liquids into each other and mix them well. Then Ellen waits for a few seconds and the liquid instantly turns into an ink like colour.

The magical effect is actually a chemical reaction known as the Landolt Clock Reaction. It actually involves 3 different solutions (read about them). The reaction happens quicker once the mixing starts and leads to a third reaction which happens immeasurably fast. It’s totally instantaneous and thus the transparent solutions turn into a bluish black iodine starch complex. As steve’s website puts it…

The sudden change from a colorless solution to the blue-black solution is the result of four sequential reactions. First, the bisulfite ions (HSO3-) reduce some of the iodate ions (IO3-) to form iodide ions (I-). Next, the iodide ions (I-) are oxidized by the remaining iodate ions (IO3-) to form triiodide ions (I3-). The solution now consists of triiodide ions (I3-) and soluble starch. In the third reaction, the triiodide ions (I3-) get reduced by the bisulfite ions (HSO3-) to become iodide ions (I-). That continues until all of the bisulfite has been consumed. Finally, the triiodide ions and starch combine to form the dark blue-black starch complex that looks like ink.

See more at: SteveSpanglerScience

Liquid Nitrogen Experiments

By Anupum Pant

Short of time and keeping up with a busy schedule, I looked around for something interesting to learn today and I found this cool video of very interesting experiments that were done with liquid Nitrogen on ScienceDump. There are 11 such experiments that are shown in the video…

The first one is a Liquid Nitrogen explosion, something like this professor did some time back. To demonstrate his students how Liquid Nitrogen expanded, he blew up a container of Liquid nitrogen to toss 1,500 ping-pong balls. [Video]

Is an Aeolipile, or a rocket styled jet engine made using liquid nitrogen A.K.A Hero engine. Liquid nitrogen heats up inside a container, expands and comes out of tiny orifices to create a jet that makes the container spin. A simpler version of it can be done using a ping pong ball (again). [Video]

The third one simply is a demonstration of what happens when you eat a biscuit dipped in Liquid Nitrogen.

Fourth one again is something you’ll have to see to get really impressed by what some solids at very low temperatures can do. A nice demonstration of something similar is done on this video. [Video]

Fifth one! Oh, the Leidenfrost effect. We’ve talked enough about it already. [Here]

Others are all pretty interesting too. The eight one probably takes the cake – brings back a dead creature to life, or does it…. But I won’t spoil them for you. Watch the video now…

The Evil Powdered Alcohol or Palcohol

By Anupum Pant

As if liquid alcohol wasn’t itself causing enough menace, now we have this futuristic powdered alcohol. They call it “Palcohol”.

All you need is, to mix a little of it with water, and there, you have your doze for the day. Other way to consume it would be to snort it for an “instantaneous high”, which by the way, is nothing less than deadly.

On an unrelated note, I find the host of this show is so adorable.

Problems

  • Palcohol certainly makes it easy for kids (and others) to carry alcohol around, and also to move it into places where it isn’t allowed (football games and concerts), which is definitely not desirable.
  • Also, the powder is highly flammable. Who wants a bomb in their pocket?
  • Another really bad thing about it is that it can easily kill you. Snorting can damage your mucous membrane. Also, since it is alcohol in high concentration, you can easily overdose on powdered alcohol and pass out.
  • The nightmare of every person, date rape, well, that just got a lot easier. Scary! How easy would it be for a creep to slip this powder into a drink of an unsuspecting victim – This is also Lacy’s primary concern (watch the video below).
  • So many new laws need to be in place before it gets available for public.

The patent to create powdered alcohol was published long back, in the 70s, but it is only now that they have got a federal approval. However, the Fed’s approval was taken back due to some issues. It is interesting to note that several other countries like Japan, Netherlands and Germany already have such products that are being sold in the market. How do the authorities in those countries  deal with this menace!

Nevertheless, Palcohol, a new and improved way to get drunk is here. It’s not going back.

Good news (?) is that it can be made at home. Read this PopSci article for the recipe.

I see only problems with Palcohol. I don’t think it needs to be in the retail market. What do you say?

Is Helium Beer Possible?

By Anupum Pant

Background

For the fizz, almost all beers have carbon dioxide dissolved in them. However, some others have also experimented with Nitrogen beers. But as fas as I know, no other gases have been used to make beers. Tell me in the comments section if you know any other gasses that have been used to do this.

But, on April 1st  Samuel Adams announced a Helium beer on his YouTube Channel. Note, the date was 1st  April. Here is the video of the announcement.

Save Helium and Science of the Fake Beer

Of course it was an April fools stunt. But what if it was real?

In his “HeliYum beer” Adam announced that, instead of carbon dioxide to create the fizz, he had used the Helium gas in the beer. In the video, as an additional effect, the new beer gas also created a funny atmosphere by affecting the voice of beer tasters. Now, I certainly didn’t like the idea of using Helium to keg beers because I’m very touchy when it comes to wasting the precious gas – Helium. Why? Well, read this Helium article I wrote some time back.

Also, I was adamant in believing if it was even possible to do that. Firstly, the date was 1st  April. Secondly, the science clearly didn’t allow this. Here’s why…

1. Helium is about 700 times less soluble in water as compared to carbon dioxide. It is one of the least soluble gases in water and only about 0.0016 g of Helium would get dissolved in a litre of beer. While, at the same conditions, 2.5 g of carbon dioxide is usually present in a litre of beer. This dissolved carbon dioxide is what realeases slowly and creates the fizz. No slow fizz can be done with Helium. Undissolved helium in beer would coalesce into one or two big bubble and…ploop, would go out as soon as the seal would break.

2. Even if Helium was forced into the beer and sealed in a beer can, it would be useless. As soon as the seal would break, all the meaningful amount of helium present inside, undissolved, under pressure, would come out so quickly (due to less viscous beer) that it would bring out a lot of beer with it. It would create a mess. And you wouldn’t be able to even bring the can near your face by the time the whole gas goes away.

Had carbon dioxide been used for the same purpose, the gas would, like it normally does, come out steadily. It would make the bubbles last.

Verdict: No. It’s useless to try to make beer with Helium unless you make it so viscous that it won’t let the Helium pass so easily. In that case, it won’t be beer really. Also, I’m not sure if the fermentation process could take place in such a viscous condition.

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Five Mundane Things That Can Be Turned Into Diamonds

By Anupum Pant

Background

Diamonds are natural things…or are they?
All of those who have bought a wedding ring, have most probably been informed at the shop that diamonds can be made in the laboratory. And these diamonds are virtually indistinguishable from the real (mined) ones. Today they go by the name, laboratory-created, lab-grown, synthetic diamonds or man-made diamonds and are available at almost all jewelers. They have the same physical and chemical make up as that of the mined diamonds. The primary difference between the real deal and the lab diamond is their price. The lab-grown ones are usually easier on your wallet.

Normally, synthetic diamonds can be made using 2 different processes – high temperature and high pressure method and Vapor deposition method. The former is used to convert most mundane things into diamonds. But the later is used too…

Note: If this post reminds you of the classic track, Diamonds made from rain by Eric Clapton, then for a minute, you might want to stop playing it in the back of your head. And for the record, no, diamonds cannot be made from rain.
Fun fact: However, scientists say it does rain diamonds right here, in our own solar system, in the planets Jupiter and Saturn. But that is for some other day.

For now, I have collected a small and interesting list for you below. Four out of 5 are made using a similar process (number one from the two mentioned above). The list has been made to realize how there are diamonds hidden and lying around you. Let’s see what are those mundane things that can be turned into diamonds, right here on earth, in laboratories. Continue reading Five Mundane Things That Can Be Turned Into Diamonds

5 Visually Incredible Science Experiments You Cannot Miss

By Anupum Pant

Here is a small list of visually incredible science experiments that will keep you visually mesmerized for a couple of minutes. Later, you’ll be left wondering about what you just saw.

The list is a small one, to not overwhelm those avid readers who follow the articles everyday. I think, more than 5 videos, is just too much wonder to take for a single day.
I do have a collection of hundreds of other such incredible experiment videos (in my bookmarks) that I’ll be sharing in the future…probably with the same heading suffixed with “part 2”.

Now without any more delay, here is the list. Have fun and do share if you like them! Ask me in the comments section if you have any questions.

1. Decomposition of Mercury (II) Thiocyanate

2. Liquid Nitrogen + 1500 Ping Pong balls

3. Dry Ice + Water

4. Quantum Trapping / Quantum Locking

5. Flying top

Harmless Flour is an Incredibly Explosive Substance

By Anupum Pant

Background

The next time you are biting off from a bread, pizza, pancake or a doughnut, you should probably take a minute and pay a silent acknowledgement to the people who work in flour mills to bring flour to your homes. Yes, because flour, the seemingly harmless cooking ingredient can be an incredibly dangerous substance – It explodes.

Wait a minute. It isn’t a minor explosion I’m talking about. I’m talking about really big explosions. Read on to know more.

Burning Flour

Flour is almost completely starch (or carbohydrate). Since Carbohydrate is nothing but a large molecule which is essentially a couple of sugar molecules linked to each other, it burns like sugar. And everybody who has tried burning marshmallows on a candle knows how easily sugar catches fire. Agreed, carbohydrate isn’t as sweet, but it is just like its cousin sugar when it comes to flammability.

So, that is how flour can catch fire. But what is it that makes it bring down full-sized buildings?

Flour in air

Flour in your kitchen’s flour container can be a very boring thing. The fun starts when the tiny flour particles are suspended in air.

Flour particles suspended in air, or for that matter, almost anything suspended in air that can catch fire, is a dangerous thing. For example, look at one of the most hazardous situation you can have in a coal mine – There is coal dust around and accidentally there is a small sparkle around it. The whole place explodes like a bomb. This has resulted in some of the worst ever mining accidents in the history.

Such explosions happen because anything that is in powdered form and is suspended in air, has a far more surface area exposed to oxygen per unit weight, than normal lumps of the same substance. This is true for industrial stuff like powdered coal, sawdust, and magnesium. Besides that, mundane substances can explode too – like  grain, flour, sugar, powdered milk and pollen.

All it takes to cause a disaster is a suspended combustible powder and a little electric arc formed from electrostatic discharge, friction or even hot surfaces – A little spark is enough.

Such settings are common in flour mills, where there is flour floating around literally everywhere. This is what caused a giant explosion in a flour mill in Minnesota on May 2nd, 1878, killing 18 workers. But that was more than 100 years ago. Kitchens are relatively safe because you don’t have enough flour in the air to catch fire and produce great volumes of air that are enough to cause an explosion.

This happens even today. From the year 1994 to the year 2003 there have been 115 such reported explosions in food processing industries in the US.

[Source 1] [Source 2] [Source 3]

Experiment

The following is a simple experiment you can do at home (obviously with adult supervision) to understand the explosive nature of a harmless cooking ingredient. [Video]

What you need: Safety glasses, Tin can (with lid), Candle, Matches, a long Straw and fine white flour

  • Take a tin can, one with a relatively tighter lid. Make a hole at the lowest point in the side wall (just enough to fit in a straw).
  • Open it up and put in a handful of flour inside it. Now is the time to put on your safety glasses.
  • Now, burn a candle and carefully place it inside the can.
  • Close the lid, insert the straw into the hole. Now blow at the base of the can, in a way that flour stirs up inside without extinguishing the candle.
  • Watch the lid pop up 10 feet into the air.

Einstein Couldn’t Figure How the Drinking Bird Worked

By Anupum Pant

Background

DrinkingBirdThe Drinking Bird is a toy which almost every one of us has heard of. If you haven’t, may be this picture of it rings a bell. Otherwise, it is a funny looking bird-head made of felt, mounted atop a glass or plastic straw, with a little bulb at its lowest point. The whole contraption is suspended at two points, which allows it to swing smoothly like a pendulum – drinking water at regular intervals, from a glass, for ever.

The amusing thing about this little toy is that, once it starts, it keeps swinging and “drinking” for ever. Upon giving it a cursory look, it seems to be a perfect perpetual machine – a contraption that can run indefinitely without an external source of energy. In reality, it isn’t a perpetual motion machine. There is a complex physical and chemical activity going on inside the toy, which keeps the simple heat engine running forever without a battery – Something so complex to deduct, that even one of the greatest Physicist ever, Albert Einstein himself couldn’t figure out the correct mechanism that keeps it running.

Don’t worry, it isn’t as difficult to understand the mechanism.

How does it work?

Assuming you have properly understood the parts of the toy, you will notice that the little bulb at the bottom of it has a colored liquid in it. This colored liquid is a chemical called Methylene chloride – A chemical that dissolves caffeine and can be used to decaffeinate coffee, teas and colas. The special property of this chemical which makes the toy work is its extremely low boiling point. It has a high vapor pressure at room temperature.

At room temperature the vapor pressure in the tube and head is high. The fluid remains in the bulb and the bird is upright due to the weight of the fluid.

The first thing you do is, you make its head dip in water. That way, the head made of felt absorbs water. The water cools due to evaporation (like our sweat cools our body), drops the temperature of the head and the bird comes up.

While swinging in the upright position, as the head cools further, the vapor pressure at the head decreases, while the pressure at the bulb becomes relatively higher. This causes the chemical to rise up the tube and it changes the center of gravity (CG). Due to the change in CG the bird tips its head back into the water.

Absorbs water and the process starts once again. It keeps on going till the bird can no longer reach the low water level. You, then have to fill up the reservoir.

Source of energy?

There is a lot going on in the toy so it isn’t really easy to point a single source of energy. However, it is pretty clear that the bird isn’t a perpetual motion machine. Anyway, watch the insightful video now. The simple toy is indeed a beautiful thing to marvel about. [Video]

Making Glow Sticks at Home is Fairly Easy

By Anupum Pant

Glow sticks or Light Sticks are so much fun and assuming you are able to get the required chemicals from a lab supply shop (online or offline), making them at home is as simple as mixing tang.
I came across this interesting video which teaches you how to make glow sticks at home. The best thing: You don’t have to worry about mixing exact measurements. An experiment definitely worth a try!

As the video tells you in the beginning, making these at home will cost you more than a ready-made glow stick. That is because the chemicals required to make it cost much lesser when bought in bulk. Nevertheless, it should be fun to try at home. If you can’t watch it, I’ve mentioned everything in detail below. [video]

1. SOLVENT: The first thing you need is Diethyl Phthalate (DEP). It is a fairly common substance because it is used a lot in detergent, sprays, cosmetics industries. Although it is clear and looks almost like water, you should avoid touching it with bare skin. In fact, none of these chemicals should be touched. Gloves are extremely important here. DEP will be your main solvent. All the magic will happen in it.

2. COLORS: The second part of making glow sticks involves the color. For this, you’ll need something called the fluorescent dyes. The ones used in the video are:

  • 9,10-bis(phenylethynyl)anthracene for Green – Orange in solid state.
  • Rubrene for Yellow – Red in solid state.
  • 9,10-diphenylanthracene for Blue – White in solid state.
  • and Rhodamine B for Red – Green in solid state.
  • Mix the blue and Yellow solutions for the white glow stick.

3. ENERGY: To make enough energy to light it up you’ll need a mixture of three chemicals. The first one is TCPO (DNPO or CPPO can also be used). It is an expensive chemical. It can be made for much cheaper [video]
The second chemical is added to keep the liquid in alkaline state. Sodium Acetate (Remember Hot Ice).
In the end, you add, Hydrogen peroxide and shake to give the final glow. It acts as an oxidizing agent, reacts to form an unstable compound, which excites the dye to an excited state. The dye emits light when it comes back to the ground state. This is the reason you need Fluorescent dyes – normal dyes won’t work.

For more of such interesting chemistry tricks do subscribe to NurdRage on Youtube.

To make a permanent Glow Stick

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Mpemba Effect – Hot Water Freezes Faster Than Cold Water

By Anupum Pant

In the past, we have seen that when it comes to estimating temperature, we are not so smart. Once again seeing the Mpemba Effect defying all known logic, reminds me to be careful about applying logic to most of the natural phenomena which are seemingly simple but in reality are extremely complicated.

By applying simple logic, a 7-year-old could tell you that cold water should turn into ice quicker than hot water would. It should, because a hot liquid contains a lot more heat as compared to a colder liquid, which [the heat]  has to be removed in order to freeze it. Yes, it is what anyone who is unaware of the Mpemba Effect would think. But, that isn’t the case with water. It turns out that a very common substance – water – is not as simple as it looks.

Mpemba Effect

Since the time of Aristotle and Descartes, scientists have noted that hot water can freeze faster than cold water (and yet the effect is not popularly known among us today). Although the effect was noted back then, the actual mechanism which caused it remained a mystery all along…until the year 2013.

All this time this effect must have been known by some other term because, it was not until the 1960s it was named “Mpemba effect”. It was named that after a Tanzanian cookery student Erasto Mpemba when he observed that hot ice cream mix froze faster than the cold mix.

Several theories have tried to explain the mechanisms that cause the Mpemba Effect. Not even one of them was convincing enough. Probably this is what propelled the geniuses from Singapore who could finally solve this mystery during the month of October this year.

What causes it?

In simple words, Hydrogen bonds cause this effect – faster freezing hot water. Normally, individual water molecules are connected by this bond called the Hydrogen bond. Think of the water molecule as a string with two bullies – hydrogen bonds – one on either side. These Hydrogen bonds pull this string from both sides. As a result, the string stretches. We’ve all fought with rubber bands and know that a stretched string has a butt load of energy stored inside it. The same thing happens with water. Energy is stored in stretched water molecules at normal temperature. This extra energy has to be removed to cool water.

At a higher temperature, the heat kind of weakens these bullies. So, the weak bullies aren’t able to pull the string as much. Now, individual molecules sit apart. They are no longer stretched. Thus, not much energy is stored in these strings anymore. They have given up energy. There is no longer any extra energy that needs to be removed. Hence, cooling is faster.

Sorry: Today I don’t have my buddy – the internet – with me. So, you won’t see any outgoing reference links today. I have a just a bit of internet (a slower 2G connection) which I’m using up to publish this.

The Musty Old Book Scent

By Anupum Pant

Note: Since I’ve been getting quite a lot of visitors on this blog now, I think it would make sense to imbue a conversational tone in my posts. At least with enough readers, I won’t feel as if I’m talking to the air. So, instead of just creating a repository for archived trivia, I’ll take freedom to write my blogs in a more personal way from now on. You’ll have to wait for comments though (Tomorrow I’ll tell you why). Till then, you can get in touch through my about page.

The state of reading

No longer does a major chunk of human population has the drive or patience to go through a long chain of black letters. Instead, we prefer a stream of individual quick-visual-gags (memes). Others like to listen to audio books while they are slashing fruits on their smart-phones; some others like to ‘read’ info-graphics instead of blog posts.
A blog post without images is quickly discarded as an uninteresting one (like mine). Nevertheless, I believe, among those billions of people on the internet now, there is a tiny chunk of people who like to read. And a tinier part of that tiny chunk of people have come here to read this. I salute you. Salute me back on twitter.

That said, I’m not against info-graphics. I love them too. Also, it doesn’t mean I’m against audio books or memes.

So, if you’ve read past the two paragraphs above, I can safely assume, you are one of those who like to read. And I think we’ll connect well if I state – There is nothing like the smell of an old book; or a fresh book for some. Both ways, I think it makes sense to book lovers.

The smell according to experts

Unike Petrichor, the smell of old books does not have a specific name but you could call it “musty” in a good way. Experts need a much more detailed phrase to communicate the subjective experience. Back in 2009, the lead scientist who looked into what actually caused the smell described it as:

A combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness. [Source]

The pleasant aromatic smell is due to aromatic compounds emitted mainly from papers made from ground wood which are characterized by their yellowish-brown color. They emit vanilla-like, sweetly fragrant vanillin, aromatic anisol and benzaldehyde, with fruity almond-like odor. On the other hand, terpene compounds, deriving from rosin, which is used to make paper more impermeable to inks, contribute to the camphorous, oily and woody smell of books. A mushroom odour is caused by some other, intensely fragrant aliphatic alcohols. [Source]

What causes the book scent

A typical “old book” smell is a mixture of fragrant volatile substances and does not comprise of any single compound. So, all books do not smell the same, as materials and printing inks vary from book to book.

As a book ages, a compound called Lignin that makes up the cell walls of wood used to make paper, starts breaking down. It releases a smell that is a lot similar to Vanilla. In fact this is the same compound that makes Vanilla smell like Vanilla. This smell is a major contributor among several other scents that make up the characteristic book scent.
Other factors that may cause the scent to vary could be due to the kind of ink and chemicals used to process the paper.

Bring it home

It is a good thing for book worms who just can’t stop smelling their books. A creative enterprise, Lucky scent, sells it in a bottle – Paper Passion perfume – sold here.

If you prefer reading eBooks and at the same time also miss the sweet  book scent, you’ll find this interesting – Classic Musty Scent and New Book scent.

Another company CafeScribe shipped “musty-smelling” scratch-and-sniff stickers with every eBook order. I’m not sure if they still do it. This was around 6 years back.

Disclaimer: I’m in no way related to the above products, they aren’t affiliate links.

Gallium Metal Melts in Your Hands

By Anupum Pant

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Atomic number: 31
Symbol: Ga

At first what seems like an uninteresting material, Gallium, in truth has, much more to it than meets the eye.

Gallium’s melting point

Like most other metals, Gallium is solid at room temperature (or liquid if it is too hot in your room). But, if it is held [in hands] for long enough, it melts in your hands, and doesn’t poison you like Mercury would. This is because of its unusually low melting point of (~29 degree Centigrade). It can melt by drawing heat from a human body which is normally at around 37 degrees.

Buy Gallium: This property, and the affordable price of $24 for 15 grams, probably makes it an appropriate gift for science geeks. They will love making mirrors at home by sticking it onto plain glass sheets.

Talking about a classic prank, it is advised to beware of the scientists who would offer spoons made out of Gallium to unsuspecting guests at a tea party. These spoons melt in hot tea and make it a potentially harmful concoction to ingest.

Since it isn’t poisonous like Mercury, Gallium is often mixed with Indium to further lower its melting point to -19 degrees. This makes it a safer option for us to use in thermometers instead of Mercury.

Interesting uses and compounds

  • Dilute sulphuric acid changes the surface properties of Gallium due to the formation of Gallium Sulfide on the surface. It no longer sticks that badly to glass, gets pulled up into a ball and starts beating like a heart when dichromate is added.
  • 98% of the world’s Gallium metal is used as Gallium Arsenide and Gallium Nitride, used in the electronic industry for making semiconductors, LEDs and high-speed circuits. In fact the laser in your Blu-Ray player is also made using Gallium.
  • Probably the most amount of Gallium used in a single place is at a Neutrino observatory in Russia. It houses around 57 tons of liquid Gallium.
  • With Silicon, Graphite and Molybdenum, Gallium is also used in ski wax to make skis more slippery.
  • Finally, nothing beats a metal that melts in your hands.

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.