YEAR 8 SCIENTISTS TAKE CHARGE

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In June, our Year 8 scientists took part in global experiment called ‘Take Charge’. Run by the Royal Society of Chemistry, the project aims to educate students about the science behind batteries and the huge potential they have as a tool in the transition to more sustainable energy sources.

Participating schools were asked to choose from one of two investigations, either building a battery or comparing coin batteries made from different materials. At Kingsley we chose to focus on the latter, as did lots of other schools around the world who all uploaded their results to the Royal Society of Chemistry’s (RSC) website for comparison. Before commencing the experiment, students watched a video outlining why batteries are such an important part of our ‘bright energy future’. To tackle the growing climate crisis we need to move away from fossil fuels and embrace electrification. A crucial part of this journey is the development of bigger and better batteries; we need them to be a sustainable storage solution to ease our energy transition. Students also learned about the science behind batteries. Here’s a quick summary!... Batteries are made of one or more cells. Each cell has two electrodes made of different materials, usually dissimilar metals. One metal forms the positive electrode and the other the negative electrode. Between these electrodes is an electrolyte - a liquid (or gel) that allows charged particles to move through it freely. A chemical reaction takes place at each electrode providing the ‘push’ of energy that keeps the charged particles in motion. Method...

Students began by soaking a coin-sized cardboard disk in an electrolyte. To make the first cell, they stacked the cardboard disk on top of a copper coin (the negative electrode) and placed a disk of aluminium foil (the positive electrode) on top. They connected the cell to a voltmeter and recorded the potential difference. Students added more cells to their batteries (up to a maximum of ten) and, each time, they were asked to predict what impact this would have on performance. The same experiment was carried out with five different electrolytes - deionised water, saline solution, sodium hydroxide, vinegar and sulfuric acid - and the results recorded.

Our students results showed unanimously that sodium hydroxide is by far the best conductor. We were excited to upload them to the RSC website and compare them with the findings of other schools. To date, 8,382 students have participated in the experiment - including from schools in China, Malaysia, Australia and Brazil - with an impressive 4,516 batteries made! The collective results confirmed that sodium hydroxide is the best conductor. This is because it causes the chemical reactions inside the cell to happen at the fastest rate, creating a bigger ‘push’ of current around the circuit. Furthermore, the potential difference (in volts) increases as the number of cells increase as, again, this creates a bigger ‘push’. Vinegar was the worst performing electrolyte as it neutralises the chemical reaction inside the cell. Working towards net zero... The experiment got us all fired up at Kingsley! It was exciting making our own batteries and seeing the effect of the different electrolytes, and it made us realise just how important scientific research is in developing solutions to help tackle the climate crisis. The RSC is encouraging us all to get involved in working towards a net zero world by signing up to one or more of their energy commitments. Visit their website to find out more: https://edu.rsc.org/globalexperiment/make-a-commitment.

Did you know? • The first working battery was developed by Italian scientist Alessandro Volta in around 1800. • Batteries ‘run out’ when one of the chemicals taking part in the reaction has fully reacted and is no longer available. • When rechargeable batteries are connected to a charger, the chemical reactions are reversed, causing them to regain their charge. How clever is that?!