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Growing crystals: Helping pupils let their inner chemist shine

Nov. 2, 2017

Potassium aluminum sulfate dodecahydrate (what a mouthful!); as complicated as it may sound, can cause quite a stir. Breaking away from the chemical compound’s common industrial and cosmetic uses, pupils in Belgium used it to create the perfect single crystal, to claim the winning prize of the 17th national crystal growing competition. Since its inception in 2000, this inspiring initiative from the Belgian National Committee for Crystallography is supported by Thermo Fisher Scientific, through donations of the chemicals required to grow the crystals.

A noble cause and a whole lot of fun

The Belgian annual crystal growing competition is open to all pupils in secondary education. Over a period of four to five weeks, participating teams (under the supervision of their science teachers) grow their own crystals in the classroom. Each team then sends their best single crystal to the local coordinator. Submitted crystals are assessed by a national jury and winners are selected based on weight and quality criteria, including the absence of inclusions (unwanted material that has become trapped inside the crystal), how well-formed the crystal surfaces are, and brightness.

This year Thermo Fisher Scientific supported the competition, providing 35 kilos of potassium aluminum sulfate dodecahydrate. This resulted in an impressive 135 crystals being submitted by 26 schools from across the country. This is part of an international initiative to trigger the interests of young people in all things chemistry, and lays the foundation for creating the scientists of the future! Our colleagues from the Geel site in Belgium (the facility which supplied the chemicals) couldn’t have been prouder of the participating pupils, who gathered at the Palace of Academies in Brussels to honor the winners.


Participants of the competition, gathered at the Palace of Academies in Brussels for the winners’ ceremony

The science (or is it an art?) of growing crystals

Growing crystals using potassium aluminum sulfate dodecahydrate is, it transpires, fairly straightforward (provided you’ve got all necessary equipment and a flair for science). First, you need to create a supersaturated solution by dissolving the chemical in hot water — remembering to cover the container to prevent contamination. You then mix a small amount of an unsaturated solution with a lot of green food dye. Once the solution is partially vaporized, small green crystals are formed, from which you should select the largest and best-formed one and use it as your seed crystal.

The final step involves attaching the seed crystal to a wire, submerging it into the supersaturated solution — which should have cooled down to room temperature — and letting it grow. All the while keeping in mind that crystals are sensitive, capricious creatures, meaning that in order to grow a large single crystal, the solution will need to be re-saturated regularly. While doing so, it’s important to remove the crystal and gently dry and clean its surface to resolve any impurities or irregularities. It is also important to ensure that there won’t be any significant temperature fluctuations at this stage, as even a low rise in temperature will reduce the saturation of the solution and the crystal will start dissolving. As such, it is a good idea to place the crystallization container in a picnic cooler or styrofoam box to avoid temperature fluctuations!


Some of the winning crystals from the competition

For pupils participating in the Belgian national crystal growing competition, the main challenge was to create a single crystal, and not a cluster of crystals. Close monitoring of the growth conditions was therefore necessary to prevent accelerated growth, which normally results in the simultaneous formation of several crystals.

Growing beautiful minds

Chemistry may be a challenging and often perplexing science, but its beauty and necessity cannot be argued. After all, the modern material world wouldn’t have been possible without the science and art of chemical bonding and synthesis. Being passionate about chemistry myself, I believe that initiatives such as the Belgian annual crystal growing competition are the perfect platform to provide young people with the unique opportunity to go beyond their textbooks, and actually experience science first hand. It is with great pride that we have been supporting the competition’s noble cause, which is in line with our own vision to contribute to the education of today’s aspiring chemists and biochemists.

Are you an educator looking to inspire the next generation of scientists?

Get in touch to find out how Thermo Fisher Scientific may be able to help accelerate the education of your students!


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