By Kevin Power, The Nobel School
As teachers, we exist as experts in our respective fields. For us, the idea and concept of a new unit and topic hits us with a sense of excitement as we begin to impart our wisdom on eager minds. The problem comes when our excitement to teach new information inadvertently creates room for misconception or mistaken information.
Typically, when I teach about catalytic converters my starter consists of recalling the combustion reaction and identifying the different compounds involved, both harmful and unharmful. During the previous year, students learned about the Periodic Table and balancing chemical equations so I assume that they have mastered or at least retained enough information to get through it. After we have briefly self-marked the starter, we move into the introduction of our main topic.
Reif’s equation for cognitive load sums up the potential problem with this route perfectly. What may seem to be a basic task in fact has many essential parts that can severely tax the working memory. If the task requires too many pieces of new information and you provide limited external resources, the task works against our goal: adding information to long term memory. Taking this into account, I decided to attempt lowering the demand of the task by scaffolding essential knowledge into individual aspects of the lesson.
In order to explain catalytic converters to students, we need them to understand many other things that may not be fully embedded in long-term memory. By helping students connect these ideas, they can bring a large amount of internal resources to the working memory without overloading it.
The pre-requisite items for catalytic converters consist of but are not limited to;
- how to identify compounds from elements (basic chemical formulae)
- use of subscript numbers and coefficients
- differences between compounds and elements
- balancing chemical reactions
- definition of catalysts
- idea of harmful gases
- combustion reactions
- haemoglobin (to talk about the dangers of Carbon Monoxide)
Of course, this is quite a heavy list of items that if not fully understood can cause overload, resulting in retention issues and worst of all indifference or behavioural issues. In previous years, this was evident as students struggled to comprehend the importance of the catalytic converter or explain their necessity in society.
Today I broke each of these down into their respective parts and visited each individually with space for practice. First, we spent time revisiting the Periodic Table followed by identifying some of our key elements. This included retrieval practice with “Groups and Periods”, referencing back to noble gases and explanations of atomic number and mass number. From elements we moved to compounds and revisited the idea of diatomic molecules as well as using numbers in complex compounds. Retrieval practice consisted of cold calling and a no-opt-out approach to increase rigor and maintain high expectations. Students were encouraged to use information from prior practice to work through challenging questions. Soon after, I demonstrated how to balance an equation and then allowed students time to do the same using my example as a resource. This process allowed students to revisit the core components needed before they could learn the new content. Over time, these components had decayed, and had I just assumed student knowledge of them they would not have been able to grasp the new material. Although there is more time and extra work involved, it allowed students to learn from small blasts of information without an overload of working memory. Soon, their schema were becoming better connected and we could begin to add tasks with a higher level of demand.
My low attaining students and even my more advanced learners were invigorated and focused intently – the likes of which I have not seen in a long time. That smile and exclamation of understanding that we all look for was across the entire classroom. I was able to reinforce concepts that my students had trouble with, and thereby gave them the opportunity to shine. I decided to push on with the lesson in the same fashion and worked this theory into my questioning. Again, I did not assume prior information and worked through my basic requirements. After demonstrating how to answer the core questions and providing an exemplar answer, students now had a resource they could refer to in their plenary. Adding a support like this meant that I could begin to increase the demand and eventually students can have more autonomy in their solving of complex questions.
Not only did student attention and disposition improve dramatically, but the work produced was sound with deep insight and explanations. Studying catalytic converters the day before half term should have brought dread and chaos but it brought an invigoration to my classroom. The excitement of my students continued as they became eager to leave and begin their independent research project. The increase in participation, positive behaviour and overall comprehension has inspired me to completely rethink my expectations and practice.
Trained in the United States, Kevin moved to the UK to take up a position at the Nobel School in Hertfordshire. Kevin is hoping in the future to continue using cognitive science in my classroom to improve understanding and increase the number of students moving to higher education of science.
CogSciSci 