Posts Tagged ‘chemistry’

If you were to ask people to name a famous scientist you are likely to hear answers such as Newton or Einstein.  If you were to ask me I would reply Mendeleev.  So why I do I think Mendeleev should be as famous as those other two guys? What did he do that was so important, I hear you cry? Well I will tell you, Mendeleev devised the Periodic Table, the most incredible document in the world of chemistry!

Mendeleev was a chemistry genius, not only did he manage to arrange the 80 or so  known elements of his time into the first ever Periodic Table, he left gaps in his table for elements he knew were yet to be discovered. Even more impressive, he correctly predicted the properties of the still to be discovered elements. If that was not brilliant enough, this was all happening in the days before we knew about atomic structure yet Mendeleev still managed to arrange the elements in order of their atomic number before atomic number even existed…that’s just totally WICKED, some would say INCREDIBLE.

If you look at the Periodic Table below it does not look very much like our modern day version but there are loads of similarities if you know where to look. The pink coloured elements are ones discovered after the death of Mendeleev but he had left the pink gaps to be filled in later. He was a very clever man.

Mendeleev's Early Periodic Table

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Non Newtonian fluids

Posted: January 4, 2012 by Mr Pimentao in Physics
Tags: , , , ,

Many people have heard of Sir Isaac Newton. He is famous for developing many scientific theories in mathematics and physics. Newton described how ‘normal’ liquids or fluids behave, and he observed that they have a constant viscosity (flow). This means that their flow behaviour or viscosity only changes with changes in temperature or pressure. For example, water freezes and turns into a solid at 0˚C and turns into a gas at 100˚C. Within this temperature range, water behaves like a ‘normal’ liquid with constant viscosity.

Typically, liquids take on the shape of the container they are poured into. We call these ‘normal liquids’ Newtonian fluids. But some fluids don’t follow this rule. We call these ‘strange liquids’ non-Newtonian fluids.

The viscosity ( how “runny” a fluid is) of a non-Newtonian fluid depends on things such as the stress, or pressure applied to them. This means that a quick change in the pressure applied to such a fluid might change its viscosity.

Cornflour solution on a speaker cone.

This is the reason that explains the formation of these cornflour “creatures” . Corn starch is a shear thickening non-Newtonian fluid meaning that it becomes more viscous when it is disturbed. The changes in pressure created by the sound vibrations change the viscosity of the fluid, and the result is fantastic. Check it out here.

Another classic example is Mr. Tickle walking on custard.

What’s the link between zebras, climate change and giant lasers?

The answer is they’re just a few of the topics discussed by some of the country’s top scientists at the GCSE Science Live! Event on the 25th November. Mr Bilton and Mrs Camm took 32 members of 11 Sci 1 to the talks held at the Dominion Theatre, London.

The event attracted around 1600 GCSE students from across the country, who had gathered to listen to five scientists discuss a range of fascinating topics.

Prof. Steve Jones, a geneticist, talked about the relative merits of the nature vs nurture argument. Prof. Sir David King, who was once the Chief Scientific Adviser to the Government, spoke about Climate Change and the problems that will need to be tackled in the future. The infamous Prof. Richard Dawkins posed the question ‘Is Evolution Predictable’ and Dr Kate Lancaster explored the use of high-powered lasers to trigger nuclear fusion reactions – a source of incredible energy. The talk was concluded by chemist Prof. Andrea Sella, who looked at the connection between chemical reactions and the patterns found in the skins and fur of animals.

The talks were delivered in a thoroughly engaging manner by scientists that conveyed their passion and love of the subject. The students really enjoyed themselves and were still discussing the lectures several days later.

The 5 scientists who spoke at GCSE Science Live!