Introduced by Mike Hollingsworth, Science Subject Adviser, over 200 members enjoyed three very different presentations from John Marriage, Mike Trevethick and Mike Gray. Each lasted 45 minutes and was followed by questions posted on Chat.
Darwin – the geologist
John Marriage introduced us to Charles Darwin the Geologist who became involved with several men who were starting to transform geology from its practical origins in mining and quarrying, to a well organised branch of Natural History.
His trip on the Beagle gave him the opportunity to expand his field experience. Wedded to the idea of a “simple model” of geology, he started to deviate, month by month, from the model he’d been taught by his mentors and was persuaded by a new movement promoting huge timescales and the slow persistent action of processes still visible.
On his return, he then became involved in one or two British geological problems which turned out not to fit with his “simple geology”, and which he explained incorrectly. This experience was a painful shock to his system; he had to admit that he’d been wrong.
His subsequent work on evolution was another “simple” all-encompassing theory which claimed to be capable of explaining everything within its scope. There were other influences too, but having his fingers burnt with geological theory was an important contribution to his well-known reluctance to publish The Origin of Species twenty years later.
Covid Vaccines are here – what are they and how do they work?
After a short break, Mike Trevethick spoke about the arrival of COVID vaccines and their efficacy. He started by explaining coronavirus and how our bodies tackle the infection, what Vaccines are, how they work and how you make one.
He showed how Vaccination tricks our body into thinking it is under attack and the need to establish herd immunity by wholesale vaccination. He described 4 ways of making vaccines and talked in more detail about the Pfizer-BioNtech and Oxford-AstraZenica vaccines. Redeployment of the BioNtech &Oxford Technology Platforms Rapid Vaccine development programmes to Covid 19 resulted in the swift development of Clinical Trials for Covid Vaccine to prove that it was safe, would prevent COVID infection and where Covid infections are high, reduce Hospitalisation, severe disease and death.
There was a good immune response in all age groups, showing Antibodies from people vaccinated with Pfizer or AZ bind to and neutralise covid virus. Mike went on to show that data from the real world on the Pfizer and AZ reduced both the risk of infection and of hospitalisation. He also covered the New Covid Mutant in UK and the South African variant.
He brought us right up to date by showing how concerns about Blood Clots on the brain with Covid vaccines are clearly outweighed by the risks of COVID. Public Health England (PHE) analysis indicates that the COVID-19 vaccination programme prevented 10,400 deaths in those aged 60 and older in England up to the end of March. Despite the fantastic progress, there’s still more to do: including people under 18, the effects on virus transmission, what happens if the virus mutates and can we mix and match vaccines.
Chocolate – what is chocolate?
Mike Gray gave us a potted history of chocolate from Mexico, to Spain and other parts of Europe by 1606. More recent history of chocolate covered developments in the 19th century and the 1890 Legislation introduced in Europe to protect chocolate which was being widely adulterated.
We learned what chocolate is legally, what milk and white chocolate are. On average it takes about 40 cocoa beans to make a 50g bar of 70% dark chocolate = a whole pod! Generally, each tree will produce 1 – 1.5 kg of dried cocoa beans per year with one year’s crop from one tree making 18 or 20 bars.
We learned about the location of coffee beans and what they contain, drying the beans and how it’s just the flavour of cocoa beans that varies from place to place. We also discovered how the grinding process had developed, the production of cocoa butter and cocoa powder and how most of Chocolate’s unique characteristics (and foibles) are due to cocoa butter. It melts rapidly in the mouth, why care must be taken with sugar crystals and the impact of low and high viscosity.
Mike took us through the various production and refining stages, conching and the continuous fat phase of chocolate. We learned that chocolate is Non-Newtonian because it has a yield value, what Crystallisation and Polymorphism are, what tempering is and the many causes of Bloom.
Mike ended his fascinating presentation on the science of chocolate by showing the many uses of Chocolate and the varied ways it can be used to make finished products by Moulding, Enrobing, Panning, Extruding, Spinning and Sculpting.
Because it was a virtual presentation, unfortunately there were no handouts!
The second Virtual meeting will take place on Wednesday 11 August and the third on Thursday 14 October. Keep an eye on the u3a Science network website for further details.