Contextualisation In Chemistry: What Does It Mean To Students?

Chemistry is a subject that underpins the fundamentals principles of many related scientific areas including for example, pharmacy, life sciences, sport science and nutrition. Much of the chemistry theory associated with these discipline areas is taught in the earlier years of these programmes. The principal focus of this paper is contextualisation in chemistry. Research in using a context-based approach will be highlighted and how this approach can influence the learning of chemistry. A review of current research in this area will also be included to support the rationale behind this research.

Firstly let`s examine learning chemistry and explore any issues and barriers that exist. As chemistry is broadly related to the structure of matter, many of the concepts in chemistry are abstract for example, atoms and elements and hybridisation of atomic orbitals. It has been shown that misconceptions in chemistry arise when students generalise these concepts (Gabel, 1999; Hofstein, 2004; Özmen, 2004). A Chemistry Concept Inventory (CCI) is being trialled by Krause et al (2004) to provide linkages between misconceptions in chemistry and those topics which reappear in later engineering courses. The aim is to use this tool of multiple-choice questions to develop pedagogy in introductory chemistry courses.

Another barrier relating to the learning of chemistry is the language, symbols and chemical structures used which can feel very new to students. Similar to learning a language, lack of understanding of specific terminology provides a barrier to learning when students encounters such terms in subsequent learning environments. Students must first understand how to convert a symbol into its meaningful representation (Robinson, 2003). Bodner and Anderson (2008) examine the difficulties faced by a good student in learning organic chemistry. Although the student attended class and read the recommended textbooks, there was a significant barrier to learning organic chemistry. This was attributed to the use of chemical structures which required `conscious thought and effort to interpret these structures correctly.` Although all the concepts and theories were explained in both the lectures and textbooks, the explanations took the form of lines, letters and curved arrows which did not correspond or link to meaningful reality for the student. The constant interplay between the macroscopic and microscopic levels within chemistry presents a significant challenge and difficulty to chemistry learners (Bradley and Brand, 1985; Sirhan, 2007). Real understanding demands the bringing together of conceptual understandings in a meaningful way. The difficulty for students is in applying their knowledge and extending it into the real world Bodner (1991). So now let`s examine contextualisation and what this means for learning and teaching chemistry.

Contextualisation or context-based approaches extends to the read world using applications as a starting point to introduce a scientific concept. More traditional approaches introduce the theory first and then examine how the theory links to applications. Contextualisation helps to answer the `why?` in students` minds. An understanding of why this is relevant, why I should learn this information helps them to focus on the topic in a more positive state of mind. Ramsden (1997) compared a context-based approach (Salter`s Science Course) versus the more traditional approaches in science teaching to pupils of age 16. The study found that students who followed the context-based approach demonstrated greater enjoyment and interest level in chemistry. The extent to which contextualisation aids understanding of chemical concepts is less conclusive. Bennett et al (2007) have reviewed context-based approaches extensively from 17 experimental studies and eight different countries. Their findings also support an improvement in attitude to science and that the understanding of scientific ideas is comparable to that of more traditional approaches. One useful and noteworthy feature of many context-based courses worldwide is that the concepts are re-visited during different points in the course (Watters, 2004). An interesting study by King et al (2008) reports the experiences of context-based chemistry programme and a content driven chemistry programme from a student who experienced both programmes with the same teacher. The student was able to make real-world connections between chemical concepts and theory. Her personal engagement and interest was increased and the student became aware of being able to identify connections and sequences of concepts. This recent initiative is still in the trial stages. A cautionary comment for the long-term future implications of using a context-based approach is highlighted: `teachers can interpret quite differently what it means to "teach contextually". Teaching contextually in this new syllabus involves using the context to influence and drive the curriculum design, it does not mean the sequential systematic introduction of contexts similar to a concept approach. Such a complete shift in teaching approach would require a change at both the secondary-tertiary interface to maintain alignment. The designs of a number of contexts which address the same key concepts have been used to revisit and reinforce the conceptual links (Kortland 2005). Regardless of how teaching contextually is defined, the need to introduce this approach in conjunction with traditional teaching or as a new curriculum design entity can only be considered a major step forward in the learning and teaching of chemistry.

Resnick (1987) found that students engage more with problems that are embedded in challenging real world contexts and have relevance to their lives. If the problems are interesting, meaningful, challenging and engaging then the students are more motivated intrinsically. As Holbrook (2005) notes, concepts such as atomic structure and chemical bonding are common topics in chemistry courses yet in daily life for example - improving the quality of the air is potentially a more relevant starting point.

Memory and Learning: Let`s examine the learning process and how contextualisation can influence the learning of chemistry. There is no learning without memory (Rose). Initially new information is taken into short-term memory where it is then either lost or passed into long-term memory to interact with information already stored there. Miller (1956) was the first to indicate that while our long term memory has a large capacity, in the absence of special circumstances our short term memory recall is limited. Most can recall 7 digits when asked to read aloud with rate of one digit per second. Short term memory is a temporary storage device which allows us to concentrate on one thing and not be consciously aware of every little bit of information that is recorded in the mind (Higbee). To perform this simple calculation (5 x 12) + 12, you would use the short term memory, first to calculate the multiplication (5 x 12) and then remember this answer temporarily before adding 12 to it giving the final answer. Also when reading a sentence it is the short term memory that retains the words for long enough at the beginning of the sentence to make sense of the whole sentence (Rose). In 1975 Craik and Tulving reported an experiment in which subjects were asked to remember words on one of three bases; the visual appearance of the words (15%), the sound of the words (29%) and the meaning of the words (71%). The figures in brackets are the percentage of correctly recalled words after only two presentations of the list. Encoding the meaning is 3-4 times stronger. So to understand a piece of information which has meaning for the person personally allows associations in the mind with other words and facts that are already known and understood. Otherwise new information without personal involvement or meaning will be processed only at a superficial level. Connections or pathways develop in the brain between neurons which become the routes through which we access our experiences. When stimulated our neurons grow dendrites, similar to branches on a tree to form connections with another neuron. The first time we learn something we are relatively slow but the next time is easier because the route has already been forged (Lucas). Experts in a given field have much more extensive connected maps in their long-term memory than novices. An expert can engage a greater depth of familiar concepts when encountering a problem or application. Students see problems more as isolated parts and not how the part fits into the bigger picture. Learning and familiarization with the overall context prior to the details of the microscopic chemistry explanations would help students to link new concepts into their pre-existing networks in long-term memory.