GCSE SCIENCE LIVE The first lecture was by Dr Kate Lancaster, a physicist who works with laser-driven fusion. Her lecture was about how nuclear fusion works, and how it could solve the energy crisis. Fusion is the process which powers stars. On earth, by fusing two types of hydrogen called tritium and deuterium, we get the products of helium, neutrons and a lot of energy. However, for them to fuse, they need to be heated to 100 million kelvin. This temperature causes the fuel to turn into plasma, a fourth state of matter. The problem with this is that this process of fusion needs to be done without touching it. There are two ways to effect this. In Magnetic Confinement Fusion, the plasma “levitates” in a doughnut- shaped chamber called a Tokamak. There is also Inertial Confinement Fusion, which uses high-power lasers to compress the hydrogen into a high-density pellet. Some advantages of fusion are no emissions, fuel is abundant and there is no long-lived radioactive waste. The second lecture was by Professor Steve Jones, a Professor of Genetics at University College London. He spoke about human characteristics and whether they are affected by our environment or whether we are born with them. He explained that in the past, we used to be killed by external agents such as filthy air, but now we are often killed by internal agents such as cancer, heart disease and diabetes. They are all heritable (passed down from genes) which are made up of DNA. There is enough DNA in one single human to stretch to the moon and back 8,000 times. He gave the example of obesity, a threat to humans in the modern world. Obese people may reduce weight by going on a diet, an environmental effect to get a normal body weight. However those born with too much of a hormone called leptin can never be fat, because of the genetic effect of this hormone. He talked about the concept of “Nature vs. Nurture”, a concept relating to this example. The third lecture was by Professor Lord Robert Winston, a biologist who studies reproductive and developmental biology, and a pioneer of IVF treatment. He spoke about the reproductive system and how fertility occurs. He showed the path of an egg and how it travels through the fallopian tubes and the defences it uses to ward off external threats, including sperm cells. He also talked about the pre-implantation genetic diagnosis, which is when you examine an embryo and remove any disorders it may have. He is now studying transgenetic technology, which uses equipment to alter the genome of a species and make it better. The fourth lecture was by an examiner who told us how the GCSEs of 2018 have changed and what the examiner is looking for when they mark your paper. He explained there is slightly less emphasis on recall and more on application, more emphasis on practical work and longer papers with more marks as there is now no coursework. He also explained how to revise and gave us some tips and techniques: You should discipline yourself by making a timetable and not procrastinate; be adaptable; use past papers constantly; get enough sleep and rest and the day before the exam, relax and not revise the night before the exam. The fifth lecture was by Professor Lucie Green, a solar researcher at University College London. Her lecture was about the sun and the atmosphere around the sun. The sixth and final lecture was by Professor Andrea Sella, a synthetic chemist from UCL. In his lecture, he showed that ice floats in water, and is the only substance to do so. The density of ice is actually lower than liquid ice – water. He explained that the reason we put ice in drinks is not to cool it down, but to actually maintain a constant temperature while you drink; ice absorbs the energy from the drink and does not let it warm up to room temperature. He then talked about the melting point of water, and how it changes depending on pressure. On the surface of the earth, where there is one atmospheric pressure, the melting point would be 0oC. But as you increase altitude, the pressure would decrease, changing the melting point. This can be seen by the graph below. Professor Sella finally explained how ice on earth found at the poles and mountains should be contained. This is because it keeps the temperature of the earth constant, and if the ice was to melt, the earth would not only have higher sea levels, but will warm up more quickly. A very enjoyable and useful day! Syed Ali, Year 10 19