Chemistry History

Today in Chemistry History – Stephanie Kwolek and Kevlar

Infographic on Stephanie Kwolek: born 31 July 1923, died 18 June 2014. Kwolek created the polymer known as Kevlar while working for the chemicals company DuPont. She also developed the ‘nylon rope trick’ classroom demonstration, which produces nylon in a beaker at room temperature. Kevlar is a polymer, a long molecule formed from the reaction of many smaller molecules known as monomers. Kevlar is used in body armour and bulletproof vests due to its high tensile strength. It is also used in fighter plane panels and wings, petrol tanks for Formula 1 cars, cut-resistant gloves, car and bicycle tyres, some ping pong bats, and some mobile phone casings. In 1995 Kwolek received DuPont’s Lavoisier medal for her research, and is still the only woman to have received this award.

Today marks the date of birth of Stephanie Kwolek, the US chemist who discovered the widely used polymer Kevlar. She also developed the nylon rope trick, in which nylon can be produced in a beaker at room temperature – a demonstration which is still used in classrooms today. In addition to this she is the to date the only woman to have been awarded DuPont’s Lavoisier Medal for outstanding contributions.

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Today in Chemistry History – Rosalind Franklin and the structure of DNA

Today in Chemistry History graphic on Rosalind Franklin and the structure of DNA. Rosalind Franklin was a chemist and  X-ray crystallographer whose work was instrumental in the discovery of the structure of DNA. She missed out on a Nobel Prize for her work as they are not awarded posthumously. Photograph 51 is an X-ray diffraction image of DNA taken during Franklin’s research. It was crucial in developing a model of DNA and confirming its double helical structure.
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Rosalind Franklin was born on this day in 1920. Her contributions to the discovery of the structure of DNA were key; she took photos of DNA’s structure using X-ray crystallography, and it was these photos that informed the work of Watson and Crick’s model of DNA’s structure. Sadly her contributions were not fully recognised until after her death, and she did not share in the award of the Nobel Prize for the discovery of DNA’s structure as the prize is not awarded posthumously.

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The History of the Atom – Theories and Models

An infographic history of the atom. Dalton identified that atoms of a particular element differ from those of other elements. Thomson discovered the electron and described the 'plum pudding' model of the atom: electrons scattered throughout a cloud of positive charge. Rutherford identified that the positive charge was concentrated in the nucleus of the atom. Bohr modified Rutherford's model by stating that electrons move in orbits of fixed sizes and energies. Schrödinger stated that electrons do not move in paths around the nucleus but in waves.
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All matter is made up of atoms. This is something we now take as a given and one of the things you learn right back at the beginning of high school or secondary school chemistry classes. Despite this, our ideas about what an atom is are surprisingly recent: as little as one hundred years ago, scientists were still debating what exactly an atom looked like. This graphic takes a look at the key models proposed for the atom, and how they changed over time.

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