Old Persean talks volcanoes
27 Jan 2015
Yesterday, Dr Mel Rodgers, volcanologist and former Perse student visited the School for this week’s ’42’ lecture.
Sixth former Izzy Picton-Turbervill attended the lecture entitled ‘Volcano – will it blow or will it flow: why volcanoes behave in such different ways’, and shares her thoughts below on this fascinating session.
“Continuing the success of the ‘42’ lectures, Old Persean Dr Mel Rodgers from Oxford University came to discuss the endlessly complex reasons why volcanoes erupt. She took us through the multiple types of volcanic eruptions, and why they aren’t all columns of explosive lava that many people imagine them to be.
A highlight was an experiment which was modelled on the ‘rubbish-bin bang’ experiment. In the video she showed of the ‘bin bang’, a coke bottle was filled with liquid nitrogen, the lid replaced and put into a bin containing water and plastic balls. The vaporising nitrogen pressurised the bottle until the plastic failed, causing the balls to shoot up into the air, just like an eruptive column of a volcano. Scaled down to fit into the lecture theatre (and to avoid unseemly levels of destruction!), Mel used a small plastic cup, a film canister, salts and small plastic balls. We all waited in anticipation for the balls to explode, and, just as we thought the experiment had failed, water and balls flew up into the air, much to everyone’s excitement. As well as being very entertaining, this experiment also gave us an insight into how volcanoes erupt when magma is under pressure.
After the lecture, the members of the Upper Sixth studying geography were lucky enough to participate in a workshop with Mel, examining the aftermath of the disastrous volcanic eruption in 1997 over the Soufrière Hills in Montserrat. We were split into five groups to represent airport workers, farmers, shelter occupants, the government and scientists. This was to show each group’s point of view, leading to an interesting debate as to how people should have reacted when the disaster occurred. I think it is fair to say that we were all shocked and puzzled at the difficulties they faced – trying to put yourself in the shoes of these people really highlighted to us the conflict of interests. For example, should the government have set off sirens to give citizens a 90 second warning of a risk, or was that essentially providing a false sense of security with a totally inadequate warning time?
It was a really interesting day, with lots learnt. Thank you very much to Mel for coming back to The Perse and sharing her challenging ideas with us.”