My interest in science was stimulated by many observations, including the night sky and books on discoveries and inventions. But the greatest stimulus was undoubtedly my firsthand experience of my first chemistry laboratory exercise, at grammar school in England.
We 11-year-olds were instructed to make a solution of light blue copper sulphate crystals – the pentahydrate chalcanthite, CuSO4 · 5H2O – in water. To that, we were then told to add aqueous ammonia drop by drop, and to note our observations. An initial blue-green precipitate of copper(II) hydroxide, Cu(OH)2, dissolved in additional ammonia to give a beautiful deep blue solution. The latter was poured onto a covered clock glass, and left for a week.
At the next laboratory class, I found marvellous, glistening, deep-blue crystals – a new substance derived from the copper sulphate. I immediately wanted to understand the source of these colour and chemical changes. It also seemed likely that with chemistry, one could make materials that had not been known before. This was confirmed for me when I read of the discovery of the first synthetic dye – mauve – by the nineteenth-century English chemist William Perkin.
Neil Bartlett is author of The Oxidation of Oxygen and Related Chemistry (buy this book from Amazon (UK) or Amazon (USA)), and a contributor to Fluorine Chemistry at the Millennium (buy this book from Amazon (UK) or Amazon (USA)).