Lab: The Supercooling of Water

This lab is actuall very simple, but it isn great way to learn about how entropy and enthalpy come together in thermodynamics. I have written an article as theory for this lab and as an introduction to these terms, so for the sake of time I will just build off of that.

The supercooling of water is something that occurs when you have water that is still in liquid form under the freezing point, 32°F or 0°C.

This occurs because in order for the reaction to occur, the gibbs free energy of the system must be negative.

The first time I attempted this lab, I failed because the water I used wasn't pure enough, so it froze before I wanted it to. Less pure water has a smaller change in entropy because it has a higher entropy to begin with. The change in entropy generally must be quite great for a reaction to occur, and in this case must be greater than the change in enthalpy times the temperature (~2nd 71K).

Grpah representing the freezing point and the nucleization point of water at the point with high entropy relative to the time of the reaction.

When the lab finally does occur, it happens because the gibbs free energy is not yet negative, because the change in entropy is not great enough. In order to push it over the edge, the bottle must be smashed down, increasing the entropy of the liquid enough to make the gibbs free energy negative, thus allowing the reaction to occur. In this case, the reaction is a physical change, but these thermodynamic laws still apply. The reaction is the freezing of the water in the bottle in front of your eyes, beginning from the hearth of greatest entropy where you hit it.

The change itself is very exciting when you finally get it to occur. Just remember to make sure that your water is pure, and keep in mind that the change in enthalpy doesnt have to be as high if the entropy of the system is great enough, and the more water, the higher the entropy.

I will leave a video of the reaction below, so that you know what to look for. Good luck!

Vinay Konuru

An Introduction to Thermodynamics and the Gibbs Free Energy Law

I recently learned about the amazing science behind a part of thermodynamics, the bases behind the both the what and why of chemistry. Thermodynamics is one of two principles that defines an experiment, with the other being kinetics. Thermodynaics deals with whether a reaction will occur. Kinetics determines the rate at which a reaction occurs. These principles shouldnt be confused, because althiugh they seem interlocked by definition, they are actually independent of each other. This is why I have decided to keep this article as an intro purely to thermodynamics and principles like Gibbs free energy.

I already told you that the basic definition of thermodynamics is whether a reaction  can occur based on the entropy and enthalpy of the the reactants. Now it's time I start throwing some definitions at you so get ready. Entropy is the so called "order" or "randomness" of the system of the reactant. For example, imagine the molecules inside a cloud of smoke. The molecules in the system are going to be moving very fast and there is a large potential for different possibilities or configurations as they fly past each other. On the other hand, a solid block of ice will have little movement on a molecular scale, mostly vibrating in place based on its known properties as a solid. Entropy can be estimated based on logic, but it is quantitativelt measured in J/K based on the SI system.

A visual to understand  entropy. As the temperature increases, a trend can be noticed of large entropy increases during state changes.

The other important principle to calculate the thermodynamics of a system in a reaction is enthalpy defined as the total heat content if a system. This is measured by the internal energy plus the product pressure and volume. This isnt as easily imagined as entropy, but the easiest way to imagine it is simply state changes. The enthalpy of an ice cube is lower than that of water vapor because the gaseous state of water has greater internal energy. The unit of measurement for this is simply Joules by the SI system.

The graph above models enthalpy and expands upon what I said above. The products of a reaction typically have a lower enthalpy than the reactants. However, sometimes an initial activation energy to kick off this reaction, which is the hump in the graph.

Now for the exciting stuff. Thermodynamics is the key to calculate the Gibbs free energy of a reaction, which determines whether a reaction can happen. In laments terms, a system always wants to obtain a lower energy state, with exceptions of course. So if we had a way to calculate the internal energy in a reaction and find whether it is increasing or decreasing, we use the gibbs free energy equation.

∆G=∆H-T∆S

H is the symbol to reference enthalpy. S is the symbol for entropy. T is the symbol for temperature. G is the symbol for Gibbs free energy. If the change is enthalpy minus the change in entropy multiplied by the temperature, measired in K, is less than 0, we know the reaction can occur This is to represent that the energy is lower in the new system, shown by the negative, than before.

Demonstrates the effect of entropy and enthalpy on a reaction. The change in enthalpy(H) must be greater than the change in entropy(S) times the temperature for the change in Gibbs free energy to be negative.

Although this is a very simplified explanation of thermodynamics, it is where Ive decided to start my journey. The laws and science of thermodynamics is immense, and it takes years of study to even get a grasp on it. I have to start at some point though, so I've decided to begin with the gibbs free energy law. I will post the lab I did, the supercooling of water, to understand these certain principles further. and some interesting issues I found to have initiallt with it. It will be exciting, I promise! The theory behind kinetics will come after that but it may be a bit delayed, because I would like to conduct a lab to understand the equations better before I try to write about it.

 Stay tuned!
Vinay Konuru

Link to wikepedia articles:

Thermodynamics equations: https://en.m.wikipedia.org/wiki/Table_of_thermodynamic_equations

Gibbs Free Energy: https://en.m.wikipedia.org/wiki/Gibbs_free_energy

Entropy: https://en.m.wikipedia.org/wiki/Entropy

Enthalpy: https://en.m.wikipedia.org/wiki/Enthalpy

Bismuth and My Key to the Amazing World of Crystals

Bismuth is quite an overlooked element in comparison to some like iron and gold. Although it may not be used in everyday life as commonly as iron, and although it may not be as beautiful as gold, it's properties are where it's magic is held.

Last Saturday, I did an interesting experiment that sparked my interest about this element. The theory behind it is the fact that bismuth has an extremely low melting point for a metal at 271.4 degrees Celsius and when it oxidizes it creates really amazing colors.

This is the one I made on Saturday, but the liquid took the shape of the soup ladle rather than the shape of the crystal it makes

I originally got the idea to make this from a YouTube video created by nighthawkinlight who creates several DIY videos. However, it wasn't until later that I realized how interesting crystals actually are. 

A crystal by definition is a solid structure that is made up of a repeating geometric pattern. This pattern is called a crystal lattice or a lattice structure. This is the most stable form of ionic compounds, but crystals can also be formed by covalently bonded molecules when all the molecules share their electrons. Common crystals that you see in every day life include ice, snow, minerals, sand and much more. In fact, 90% of solids are crystalline. 

I started off with my experiment by purchasing 100 grams of bismuth off of Amazon.com for about 6 dollars. Although this is quite an expensive rate, the product is worth it. Utilizing its low melting point, I created a molten form of the metal using a soup pot as a crucible. Then I poured the pure molten metal into a soup ladle leaving the impurities behind. As the molten metal cools, it is exposed to the oxygen in the air. By letting it cool, you can create something similar to the picture above. 

However, I wanted to create a full crystal though; not just a mold of the bottom of a soup ladle. This is when I found something called the Czochralski process, and I used it to redo this experiment a few hours ago.

The Czochralski process is one used by the industrial manufacturing of silicon wafers for semiconductors. The process is defined by taking a seed crystal and dipping it into the molten metal until crystal starts forming around it. Then the crystal is slowly taken out as the crystal continues to grow around it. This creates a long crystal.  A seed crystal is a part of the solid crystal that you are trying to create that speeds up the reaction decreasing its kinetics, because the base of the crystal doesn't have to be formed based on random molecular movement. I will leave a link for a further explanation of the idea of a seed crystal at the bottom of this post. 

However, the process of putting the seed crystal into the molten metal while both accounting for the thermal gradient(the idea that you don't want the seed crystal to melt on contact with the hot liquid metal) and the fact that you have to have some way to draw out the seed crystal slowly. In order to solve this, I froze the seed crystal for a few minutes. Then I used a piece of clay that I wedged the seed crystal into. This was my apparatus to slowly draw the crystal out with. Other things that could work include a hot glue gun stick but an iron rod would work best due to the similar crystalline structure between iron and bismuth. 

This process can be used for any metal that can form a crystal, so I decided to try it with the the bismuth. Below shows my attempt. It created a very small crystal, but it's still a start. I could have created a better crystal, but the bismuth cooled very quickly when I poured it into to the soup ladle. I still got the crystal to form around the seed crystal, but the surrounding metal cooled forming a separate crystal that stuck to the soup ladle. 

Crystal that grew off of the seed 

Crystal that stuck to the soup ladle

I may repeat this experiment in the future using a greater amount of bismuth, better equipment, and now a better understanding on how to create a larger crystal based on the mistakes that I made this time. I highly recommend you guys at home trying this same experiment because actually getting to see the melting and cooling, and see the different oxidized layers is something that is much more valuable that simply watching a video or reading an article. I will leave links of all the videos I watched and sources I read so you can get a better understanding of the process that is going on before you conduct the experiment. Good luck and I hope that you end up with some good crystals.

Nighthawkinlight video: "How to Make Bismuth Crystals"

Explanation of seed crystals: https://en.wikipedia.org/wiki/Seed_crystal

Czochralski process: https://en.wikipedia.org/wiki/Czochralski_process

Other sources: 

https://www.nde-ed.org/EducationResources/CommunityCollege/Materials/Structure/solidstate.htm

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=bismuth%20melting%20point

https://www.youtube.com/watch?v=ObDL3hIGuIU

Note: I would personally recommend not using any utensils in this experiment that you intend on using later on, because once the bismuth cools on something, it will most likely never come off and never be clean again. Also, you may want to wear gloves whenot dealing with the molten metal so you don't burn yourself if you mess up!

Gels are AMAZING! (and a little bit about Sodium Polyacrylate)

A few days ago, I did an experiment with water gel powder (sodium polyacrylate) I bought online. The special thing about this chemical is that it is a polymer than can absorb over 400 times its volume in water. This causes it to create a gel on contact with water, which is why it is used in diapers and as a thickening agents in detergent. However, this got me interested in gels in general.

A gel by definition is a cross linked polymer that makes up a 3D structure encompassing a liquid and holds it together through surface tension. In laments terms, a cross linked polymer is a complex molecule made up of several covalent and ionic bonds. Then, when a liquid is added to this solid, it "traps" the water around it creating a gel.

Gels are a confusing topic because of the fact that its state and properties all depend on what aspect you are looking at it. If you are talking about the skeleton structure, it is a solid, but the liquid trapped in it is still a liquid. However, gels are still extremely important both in everyday life and on the frontier of science and technology.

You don't have to look very far to find a gel in your everyday life. There are plenty of things made of gels from toys like water beads to things like re-freezable gel packs. However, they are also used NASA shuttles in technology like aerogel.

Aerogel is an invention that was created in the 1930s and was the result of keeping a gels solid structure while dehydrating it. The outcome was the least dense solid known to man to this day. It is used as an insulator of the liquid hydrogen and liquid oxygen fuel tanks on a space shuttle in order to keep it in liquid form. Without this material, we wouldn't be nearly as successful at getting into space as we are today.

I hope to do further research into gels soon, but for now I'll leave it here. Gels are grosely underestimated for their significance in our every day lives and how amazing they truly are. The next time you see a diaper, just think about the science behind it. A dirty diaper might smell horrid, but it's also amazing.

Biuret Reagent Protein Test

Yesterday I conducted an experiment with Biuret Reagent, am indicator of peptide bonds that transmutes into a purple color when in contact with a protein. I did this with a goal to identify if almonds genuinely did have a large amount of protein and was a viable source of it during the day.

In order to conduct the test, I used water the Biuret reagent, protein powder as a positive control, water as a negative control, and crushed almonds.

The first step was create an aqueous solution with the substance being tested in it or water that has been decanted out of it. This can be done by crushing the substance, putting it in water, and after letting it sit, and decanting the water out. This means slowly pouting the water out without letting the substance get in.

Next, you put an equal volume of Biuret reagent in the water. Mix the reagent in until a color change occurs. The concentration of purple in the new solution reflects the concentration of peptide bonds in your substance, and thus it reflects the amount of protein in it. the deeper the purple, the greater the protein content.

The liquids in these beakers are water, dosa batter (Indian bread), almonds, and protein powder

(left to right)

Now back to the test I conducted. The protein powder turned dark purple and the water turned blue as expected. Then, I tested the almonds and I found it turned clear purple. This ascertained that almonds do in fact have a high protein content in them. Along with this, it showed that the protein powder had a even greater amount of protein that almonds.

In the next few days, I plan to conduct an experiment to test for the concentration of sugar in a substance, however this time I will go further by trying to calculate the actual amount of sugar in the substance. I will be testing chocolate syrup because it will be easy to turn into an aqueous solution. I hope you learned a little from this post about the way to measure protein content in food and encourage you to try it yourself

Sodium Silicate

This weekend I conducted an experiment with sodium silicate that I bought online. The product was a rubber like ball that was both bouncy, but brittle after a certain point. The compound was created by reacting 40 ml of sodium silicate with 10 ml of isopropyl alcohol and mixing them created the substance almost immediately. The reaction online involved ethyl alcohol, so I want to further research the reactive properties of different alcoholsizes and test what differences between the products.

Sodium silicate is NOT actually used to create rubber balls due to the fact it can break, however, it is commonly used as an industrial cement to create cardboard. Sodium silicate is also frequently used as a drilling fluid to avoid the collapse of boar walls and is used by builders to decrease the porosity of cement through a reaction that permanently bonds it to the surface. The best use I saw online is as a coagulation  agent in waste water treatment. I will further explore sodium silicate over the next few weeks.

The New Frontier: Nano Technology is the Future

When Columbus found America, he uncovered the "American Frontier." When we defied the barrier
of gravity and reached space, that was known as the "Space Frontier." Since Richard Feynman's famous speech in 1959, where he stated, "There's plenty of room at the bottom," the race into the nano-Frontier began. The book The Coming Era of Nanotechnology written in 1986 by Eric Drexler setting up the basis for the decades to come. Now about 30 years after, scientists are on the verge of breaking through and opening up the world a little wider but on a tiny scale. This new nano scale technology is the "New Frontier."

So what is nano technology? Nano technology is a new and budding field that utilizes molecules to create machines, known as molecular machines. that are just are generally between the size of 1 to 100 nano meters long, tall or wide. To put this into perspective, a piece of paper is 100,000 nano meters thick. This means that up to one hundred thousand of these machines stacked up on top of each other to equal the thickness of width of that piece of paper. It's astounding and these machines shouldn't be underestimated.

The importance of this field is obvious and has certainly been recognized in recent years both by world class scientists and the Swedish Academy who award the honorary Nobel prize. The 2016 Nobel prize in chemistry was awarded to Jean-Pierre Sauvage, Sir J. Fraser Stoddart, and Bernard L. Feringa jointly for research on molecular machines. This research is said to make the basics of molecular machines in the future because they showed the world how to connect our understanding of molecules to create engines, conductors, axles, rotors, and much more.   

There is currently research going on in several universities and institutions around the world who are trying to learn how to utilize these machines. For example, they are making remote controlled nano-rockets, nano "carrying packages" that bring necessary drugs and antibiotics to parts of the body that we can't. They are making nano cars, like the one shown in the picture, factories, and even malignant cell removers to fight cancer.  The more research goes into this field, the more it becomes conspicuous that this is where the future lies. But how are these complex machines being created by a few molecules in a lab?

These machines are created by synthetically created bonds that are heavily controlled by the chemist who is making them. However, this is a lot more difficult that it sounds. Molecules are constantly moving and it is very tough to control what it will react with, where it will move, and how it will bond with the other parts of the machine. A few chemists have gotten extremely creative in the last few decades on creating various structures that could come together into the astounding creations I spoke about b. I would recommend watching the videos below to get a better understanding of how everything comes together.

 These same scientists also figured out how to control these machines by using certain switches turned on and off by certain changes in the environment. These changes include triggering a reaction, or interlocking two molecules together to make one that could control the other. One type of engine that has already been created by a team at Rice University in 2006 used carbon molecule's that rotate when exposed to specific frequencies of light. An application of this that has already been implemented and is shown in the video linked below is the nano car that I was talking about earlier. They are amazing, and when I first saw it, it seemed like I was looking at the first step into the future. I believe this is how people felt when they saw the Wright brothers fly into the air or when man first laid foot on the moon. 

 Don't worry if this is still very confusing, and I understand since it is to me too to be honest, but the field is just getting up and running. The more research that goes into it, the clearer everything will become. But why does any of this matter? Why are people dedicating their lives to the research of going small, and how can this lead to dreaming big

The possibilities that were created by the research of these 3 scientists and their innovative way to make nano engines and machines were revolutionary. By using these machines, we could create anything at a smaller scale that ever before. The applications are endless and the future is open. In the next 10 years, scientists predicted, nano factories will have been created to create many machines for every day use. The future is small and it's coming a lot faster that it may seem. This is the new frontier.



Check out:
Research done by Rice University:
https://www.newscientist.com/article/dn9004-nano-car-gets-an-engine/


Nobel Prize Research Explanation and very amazing things that have been created using nano technology and future ideas including the Nano Car and the antibiotic carrying rockets I talked about! I would highly recommend watching both of these: