CAJ 3 - How was graphene discovered?

Phillip R. Wallace was the first to study graphene. In 1947 he studied graphene as a limiting case for theoretical work on graphite. The earliest TEM (transmission electron microscope) images of few-layer graphite were published by G. Ruess and F. Vogt in 1948.

Gordon Walter Semenoff, David P. DeVincenzo and Eugene J. Mele discovered in 1984 that the electric current could be theoretically carried by effectively massless charge carries in graphene.

S. Mouras is the first to mention the name graphene in 1987.

In 2004 graphene crystals were first isolated by two University of Manchester scientists, Andre Geim and Konstantin Novoselov.

(Andre Geim and Konstantin Novoselov)

Geim and Novoselov were trying to make graphite as thin as possible using lab equipment. They were struggling for months as they could not  make it thinner than 10,000 layers. After their work the lab surfaces were often covered in graphite and they would use scotch tape to clean it. Most of the time they would just look at the scotch tape to see what was happening to the graphite but would then throw in into the trash can. One day, instead of throwing it away, they decided to look at it under the microscope. They saw transparent pieces of graphite – graphene.

It is a true miracle that Geim and Novoselov continued their research on graphene because they wanted to give up on it since they overheard that other scientist at the university also use Scotch tape to clean graphite before putting it under the lens.

(a TEM image of the porous graphene)

The two scientists were first very surprised by their discovery because their physics intuition told them that this material should not exist since we live in a 3D world and graphene is a 2D material. However, they found a way of transferring the ultra-thin flakes of graphene from Scotch tape to a silicon wafer. After succeeding, they were able to examine the electrical properties of graphene.

Andre Geim and Kostya Novoselov were awarded the 2010 Nobel Prize in physics for their work and experiments regarding graphene. They continue to research graphene and other related two dimensional crystal materials.

The Nobel committee was not just blown away by the discovery the two scientist had made but also by the way they did it. The playfulness the two scientists showed while experimenting with graphite was the key to their success. “A playful idea is perfect to start things but then you need a really good scientific intuition that your playful experiment will lead to something, or it will stay as a joke for ever,” Novoselov says. Geim is known in the scientific community for his playful experiments. In 1997 he levitated a frog to demonstrate his work in magnetism.

XOXO A.

P.S. Many great discoveries that changed the world were accidental. It seems that sometimes the only thing standing in the way of a great discovery is a little bit of luck.

Isaac Newton was supposedly sitting in his garden when he discovered gravity. He saw an apple fall straight down from a tree. He wondered why they apple never falls upwards or off to a side. Newton soon discovered that all things fall straight down and that there is an attractive force pulling them down. Twenty years after that the published his theory of gravity.

In 1927 Fleming was experimenting with the properties of staphylococci. Before leaving his laboratory in August for holiday with his family, he had stacked all his cultures of staphylococci on a bench in a corner. After he returned, he noticed that one culture was contaminated with a fungus, and that the colonies of staphylococci immediately surrounding the fungus had been destroyed. Other staphylococci colonies farther away were normal. Fleming then grew the fungus in a pure culture and found that it produced a substance that killed a number of disease-causing bacteria. He identified the mold as being from the Penicillium genus, hence calling it penicillin. 

CAJ #2 - Difference between graphine and graphite

Graphene! What comes first to your mind? Did you, just like me, think that graphene is the material used in pencils? If you did, you were wrong. The central core of a pencil is called graphite. Graphite is a mineral that naturally occurs in metamorphic rock in different continents of the world. It contains two layers of carbon sheets and each layer contains very strong bonds. The layers of graphite are able to slide across each other. Graphite's abillity to conduct electricity and heat well makes it an outstanding material. Graphite can be found in pencils, batteries, brake linings, refractories and many other products.

Graphene is extracted from graphite. It is entirely composed of carbon atoms forming only one single layer of graphite. The two-dimensional crystal in only an atom thick. No material is thinner than an atom because if it were, it would not count as a material anymore. This means that graphene is one of the lightest and thinnest materials in the world. A square meter of graphene is a thousand times thinner than paper. Furthermore, graphene is one of the strongest materials known to mankind. It is about 200 times stronger but six times lighter than steel. A single sheet weighing only 0.77 milligrams can support a 4kg cat. Another astonishing property of graphene is that although it is only one atom thick, it is visible with the bare eye.

Graphene is almost entirely transparent. It is impermeable to gasses, even those as light as hydrogen or helium. Graphene is often called „the most diverse material known to mankind“ because of its many properties that are only exploited when graphene is combined with other materials, including gases, metals, and sources of carbon. Chemical components can be added to its surface to alter its properties. 

For a long time copper and silicon have been considered one of the best conductors of heat and electricity. However, the discovery of graphene showed otherwise. Graphene conducts electricty a thousand times better than copper. In comparison to silicon, graphene is better bacause it is highly flexible, not brittle and conducts electricity much more efficiently. 

XOXO A.

Migrant Mother - Description

Depressed, hopeless and gazing into space, Florence Owens Thompson depicts the sorrow surrounding her. She is in the center of the photograph, taking up most of the image. Her arm is supporting her head, looking like she is in fear of the future. The long and bony fingers are touching her narrow and dry lips, which have not tasted proper food and clean water for quite some time. Deep wrinkles around her mouth and eyes make her look older than she probably is, as well as revealing her concern for the family's future. The mother is wearing a checked shirt and a vest that look old, torn and itchy, as if they were made out of burlap. Hidden in her arm lies an infant wrapped in a dirty blanket. Next to the mother are her two older children leaning on her shoulders. Both children are not facing the camera but have instead buried their faces in their hands. It seems as though they are trying to hide behind their mother where they feel safe and protected. What can be easily noticed by looking at the children is that they have the same hairstyle, namely a bowl haircut. The light hair color of the child standing on the viewers right side makes a good contrast to the mother’s and other childs dark hair. Last but not least, the pale background illustrates the hopelessness and bleakness of her situation.

(237 words)


XOXO A.

#CAJ1 - Graphene and other super materials...

“Graphene and other super materials“ is my CAJ topic. The list we could choose from contained various interesting topics but I chose this one because I wanted to know more about graphene and how it could possibly change the world we live in. Before doing research I did not know much about graphene. I knew that it was one of the three naturally occurring allotropes of carbon, and thought that graphene is the material used in pencils. However, while doing research I discovered that graphene and graphite are two different things and are not to be confused. You will be able to find out more information about graphene and graphite in my blog posts. In the posts that are to follow I will also write general information about graphene, how it was discovered, how it could change the world, what green technology has to do with graphene and much more. I will also try to incorporate videos and pictures to help you visualize what I am writing about. No one can really predict how graphene will influence our future but it is sure that its possibilities are endless. I will not only focus on graphene but will also try to introduce you to other super materials such as stanene. I hope that you will learn something new by reading my blog posts and realize what a great and significant discovery graphene really is.  

XOXO A.

House of horror

Prior to entering the “house of horror“, as the neighbors have been calling it since the recent discovery, police officers had no idea what was awaiting them. At first glance, the house seemed like every other in the neighborhood, a swing hanging on an oak tree in the garden and a flower path leading to the entrance door of a small family house in Lancashir, Great Britain. However, the inside was not as picturesque as the outside. The smell of a rotten corpse hit the police officers as they opened the door, making them want to vomit. The wooden floors were completely covered in animal feces and leftovers. Dogs and ferrets were moving around freely. In a room covered in trash, in the back of the house, a 4-year-old was lying on a dirty mattress. 

(135 words)

http://www.dailymail.co.uk/news/article-2596730/Mum-jailed-child-neglect-seriously-ill-son-4-living-home-absolute-squalor-crammed-TWENTY-uncaged-ferrets-FOURTEEN-dogs.html