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Chulmleigh Community College

Chulmleigh Community College, Chulmleigh, Devon, EX18 7AA

A Pollutant's Tale

Visiting lecturer speaks to Year 9's

Dr Tim Harrison, lecturer in Chemistry and Science Education at Bristol University, has travelled all over the world with his lecture/demonstration on the science of air. The Royal Society of Chemistry sponsored him to bring this to five schools in Devon, and we were lucky to be one of the five.

On Friday 13th February, just before half term, Dr Harrison spoke to all of our Year 9 students.

He began by comparing the planets in the Solar System and their atmospheres, pointing out how different Earth is to all the other planets. Instead of an atmosphere of carbon dioxide and methane, which most other planets have, Earth has nitrogen and oxygen.   Most of the universe is hydrogen and helium, two very light gases, one of which is very unreactive, the other of which explodes when set alight.

He went on to show us how nitrogen is a very unreactive gas, but this property actually makes it very useful. Nitrogen boils at -1960C, which is far colder than any place on Earth. Using liquid nitrogen he demonstrated how this affects the properties of things like rubber, how it expands when turning to gas, and how this can be used to inflate and explode balloons.

Turning from nitrogen to oxygen he illustrated the reactivity of oxygen, making it from hydrogen peroxide and a catalyst and producing an overflowing table full of bubbles with the help of washing up liquid. Dr Harrison explained the use of oxygen in explosives, comparing a sealed detonator with an open one and filling the hall with smoke.

In the last few minutes he turned our attention to carbon dioxide, showing some of the properties of dry ice (solid carbon dioxide), singing frying pans and more smoke!!

I am very grateful to Dr Harrison for including us in his schedule, and to the RSC for sponsoring his tour of Devon. Our Year 9 were encouraged and enthused to consider science subjects as they select their GCSE options.

Nick Brown, Science Teacher



Comments from students:

The science lecture on the last day of term was really enjoyable and really fun to watch! He showed us a range of different experiments that linked to chemistry and there was a well thought out slideshow presentation too. He explained everything very well and gave a brilliant understanding of some aspects of chemistry. :)  Jess Waters.

I really enjoyed the visit from Dr Tim Harrison. He showcased the type of things that we aren’t allowed to have in schools, things such as liquid nitrogen and hydrogen gas. He also advertised to us Bristol University and got us involved with experiments. He did this by asking us questions about certain aspects of the experiments. It was really interesting and if I had the choice I would ask him to come back to the school.

Michael Corfield.

The lecture we received with Dr Tim Harrison was a greatly interesting experience. I really enjoyed being able to witness the reactions of the experiments face-to-face, as they were carried out using expensive equipment which is usually unavailable to schools. I also really liked the simple way he explained very complicated ideas, as it meant that I could build on the information he gave to form a clearer idea in my head, leading to a greater depth of understanding of the reactions being demonstrated.  The reactions he showed us were intriguing, and left me thinking for a long time after he had left. For example, when he showed us how helium and hydrogen reacted differently, before asking us if you would be able to explode the gas giants in our universe. The answer was no, as there is no oxygen to burn in space. This made me think about the differences between the planets in our solar system, and how different environments can affect an experiment to extreme levels.

Overall, I thought that the lecture was engrossing, and I feel privileged to have had the demonstration from Dr Harrison. 

Olivia Jenkins