For centuries people have dreamt of using alchemy to transform mundane materials into far more precious resources. One of the most famous stories of alchemy is King Midas in Greek Mythology, who could turn anything he touched to gold, even his daughter in an unfortunate incident. Fortunately, at our latest SciBar “The Alchemist’s Dream” nobody was turned into a golden statue and instead we were led through a lively and energetic showcase of microchemistry by our own “alchemist” Bob Worley.
Bob Worley is currently the chemistry advisor for CLEAPSS (Consortium of Local Education Authorities for the Provision of Science Services) who advise and support practical science work in schools, so naturally he was an excellent choice to lead this Scibar. He was joined by his “fellow chemistry nerd” Andreas Tretiakov, who has spent years working as a science technician and enthusiast. Together they made an entertaining duo bouncing off one another to create an engaging session for all who attended.
Since this event involved a large number of chemistry practicals and demonstrations we had to move from our usual venue to one of the science labs at the City of London Academy, Islington. As many of us haven’t set foot in a school laboratory for many years, this was a nostalgic setting, but exciting nonetheless.
So what did we do? Microchemistry does exactly what the name suggests, it was all on a small scale. Some of the first few experiments highlighted just how beautiful chemical reactions can be. Flame tests burnt in a spectrum of colours depending on which elements were added to them, for example potassium burns with a lilac flame and copper will give a blue-green flame. We also had a go at precipitation by diffusion where we introduced two different compounds on either side of a droplet of distilled water, where the two compounds meet in the middle they create a colourful precipitate.
Lead Nitrate and Potassium Iodide meet in the middle and form a yellow precipitate of Lead Iodide.
Andreas presented us with another exciting experiment where we had a go at making instant “stalagmites”. He did this using a supersaturated sodium acetate solution, which means that the solution was heated up so that extra sodium acetate could be dissolved into it. In the same way that you can dissolve more sugar into hot water than cold water. Once this solution is cooled the sodium acetate stays in its dissolved state. The fun thing is that when you pour it onto a crystal of sodium acetate the solution instantly crystallises and you can build up a tower by slowly pouring more and more on top.
Some of the sodium acetate stalagmites we made.
Finally, it was time to try some proper alchemy by turning copper into “silver” and then “gold”. We used electrolysis to draw zinc ions out of a zinc nitrate solution and plate them onto a piece of copper giving the silver appearance. Then you can gently heat the zinc coating on the copper and the two metals fuse together to form brass. As brass has that lovely golden colour, that is as close to true alchemy as we came. We even repeated this procedure with a 1p coin and made ourselves some novelty souvenirs.
The evening finished with a bang as Bob used a small Hofmann Voltameter to produce hydrogen and oxygen for rocket fuel. Using that he launched several small rockets across the lab. Many thanks to Bob and Andreas for the hard work they put into preparing the evening.
I’ll leave you with this joke: Silver walks up to Gold in a bar and says, “AU, get outta here!”
Reporter: Ben Johnson-Newbery