Perse chemistry students enjoy Science Live event
26 Nov 2019
Jude Burling and Minjae Kim (both Lower Sixth) share their experience of attending the Science Live conference in London, featuring talks from five of the country’s leading chemists.
The first speaker was Dr Suze Kundu, who gave a lecture on Adventures in Nano Scale. She explained the differences between working at such small scales compared to conventional chemistry, using the example of graphite and graphene and explaining how fast the latter could conduct heat. She was able to show one of the ways in which nanotechnology was making a meaningful difference to the world through buckminsterfullerene, a tiny ‘ball’ that can be made one atom thick, which scientists believe could be used to target cancer cells in the body. Despite the fact that humans have only recently started to use nanotechnology, Dr Kundu revealed they occur in nature from the way that butterflies colour themselves, to waterproofing on lotus leaves and geckos’ feet sticking to walls.
The next talk was on a completely different scale, going from nanotechnology to the world around us. An around-the-world tour of atmospheric chemistry from Professor Lucy Carpenter looking at both the history and the science of air pollutants was especially interesting. Scientific papers on air pollutants and their adverse effects date back to 1755 where P Potts linked chimney sweeps and the soot they breathed in to consequential testicular cancer. However, air pollution did not get widespread interest until the London smog of 1952 when thousands of people died due to the air quality. This led to the Clean Air Act of 1956 which became a template for similar acts in other countries ever since. The two main types of pollution Professor Carpenter focused on were the ammonia from farming and VOCs (volatile organic compounds) from consumer products. Ammonia is dangerous in the atmosphere where it can react with either nitric or sulphuric acid to form ammonium nitrate or ammonium sulphate, which are particulate in nature. Professor Carpenter finished off the talk by encouraging the audience to change their ways of life to prevent further atmospheric pollution.
The third talk was given by Professor Peter Atkins and was much more fundamental and abstract than the previous lectures. Titled Energy and Entropy, it was based on the zeroth, first and second laws of thermodynamics. Professor Atkins began the lecture by talking about Isaac Newton, who had no concept of energy and only referred to forces. Energy did not become a scientific term until it was used by Thomas Young in April 1807. Professor Atkins believes that energy has more applications due to the fact that it is less tangible and therefore does not limit itself to specific scenarios. The zeroth law of thermodynamics states that if two objects are each of the same temperature as a third then they must be the same temperature. This introduces temperature as a quantity which can now be used. For example, Professor Atkins showed that for positive temperatures, lower energy molecules were exponentially more common in a substance than higher energy molecules and, thus by reversing this, explained how to get negative temperatures in Kelvin. Through the first law, which shows that the total energy in the universe must remain constant and was proved by Noether due to the symmetry of the flow of time, he showed the difference between two different energies of work and heat. The difference lies in the randomness of heat and the uniformity of work, which is why fire was used long before combustion engines. Professor Atkins finished off by telling the audience that the total energy in the universe is equal to zero due to positive energy being cancelled out by negative energy. He completed the talk through the second law which states that entropy must increase over time and that the universe is becoming more disorderly. This is true even when entropy seems to decrease. For example, photosynthesis is making ordered molecules out of disorder. However, the energy this process requires comes from nuclear fusion in the sun, which increases entropy.
Dr Peter Wothers came next with a detailed history of the periodic table, since 2019 is the International Year of the Periodic Table. The concept that everything could be broken down into a small number of substances originated with the Greeks who believed that everything was made of earth, air, fire and water. The first scientist who tried to group elements was Lavoisier, who separated elements into metals, non-metals, gases and earths. Already elements which would end up in the same group were appearing close to each other. In 1806, Jane Marcet released Conversations on Chemistry which had a list of elements (alongside light and heat which were believed to be elements as well as ‘earths’ which turned out later to be metal oxides). In Marcet’s book, atoms were again grouped and also the ‘earths’ were split up such that Group 2 oxides were together and Group 1 hydroxides were together despite no-one knowing what they were. In 1805, Dalton first tried to calculate atomic masses but was mostly unsuccessful.
The final talk was given by Professor Andrea Sella on Nerve Agents and Chemists’ Dirty Secrets, which revealed the chemistry and dark history of nerve agents and other poison gases. Chemical warfare is present throughout history. For example, the Hittites tipped their arrows in snake venom to kill their enemies. However, chemical weapons only became widespread in the First World War where tear gas, chlorine, phosgene and mustard gas were used, first by the Germans and then by the British. During the Second World War, the Nazis used chemicals which had been developed as pesticides in order to create nerve agents and tested them on Jews in Auschwitz. In total, the Nazis created 12 tonnes of chemicals where mere milligrams would kill a person, however most were never used. He traced history through the Cold War, Iraqi and Syrian attacks.
In our opinion, the best talk was given by Professor Peter Atkins. He had a subtle but effective sense of humour to make us understand difficult concepts such as the Boltzmann Distribution. The quality of the lectures and the fun we had during the trip made it worth it.