Chemistry is an abstract subject riddled with possible misconceptions and areas for confusion. One of the educationalists who made great contributions to tackling this was a Scotsman, Alex Johnstone. He approached chemical education from an information processing perspective, which views the mind in a similar way to a computer. The best way to deliver chemistry to young people, he argued, was to introduce challenging ideas in a concrete way first of all. There is perhaps no more concrete of examples to students than food and drink, and these have worked wonders for engagement and understanding.
To demonstrate the concept of conservation of mass in chemical reactions, it is common to carry out reactions on scales to show that mass is not created or destroyed. Inspired by Johnstone, I instead bought a pack of microwave popcorn and asked my Year 10 pupils to predict whether the mass of the pack would go up or down, or stay the same. To my surprise, the pack lost mass as well as whetting the appetite of the class before lunch. Students explained that this was caused by the pack not being air tight, allowing steam to escape. When it came to chemical reactions, they had little difficulty then applying their knowledge to explain mass changes in open and closed systems.
Popcorn typically goes down well with a drink however, and it was a 2L bottle of Pepsi Max which served me in demonstrating trends in the Periodic Table to both Year 8 and Year 10 classes. Using the bottle as an electron, I asked one student to hold onto it closely while another tried to take it off them. Of course, the ‘electron’ was held. I then asked the student to hold the bottle at full arm’s length, and repeated the exercise. The bottle was easily taken, and each class managed to use this to explain why elements lose their electrons more easily as their atoms get bigger.
Last but not least, chocolate. When tasked with teaching bottom set Year 10 classes about chemical formulations, I looked to the ‘concrete first’ approach for help. Chocolate is a complex formulation of cocoa, sugar, milk, and other ingredients, and the composition affects how it looks, tastes, and feels. My technicians were able to find the best white, milk and dark chocolate money could buy at Asda, and the students did the rest. Initially in disbelief at being allowed to eat chocolate in a science lesson, the students made excellent observations about how the different chocolates tasted, snapped, and melted. Students with usually very weak literacy skills used a wide range of good words to describe what they saw and relate these to the formulation of the chocolate.
The research literature shows that understanding is stronger if the learner actively engages with new information. In turn, this is more likely if that information is presented in relevant and relatable contexts. For this approach, Dr Johnstone, both my students and I have you to thank.
Further reading: The biggest contributors to 'meaningful learning' and its relation to engagement were Ausubel and Novak and a nice research paper, looking at students doing compulsory chemistry at American universities available freely, is: Grove, N.P. and Bretz S.L. 2012, A continuum of learning: from rote memorization to meaningful learning in organic chemistry Chemistry Education Reseasrch and practice, 13, 201-208 Accessed via: http://pubs.rsc.org/en/Content/ArticleLanding/2012/RP/C1RP90069B#!divAbstract (you may need to cut and paste this into your browser)
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