Topic XVI Investigative Study in Chemistry (20 hours)
Chapter 4 Learning and Teaching
4.3 Approaches and Strategies
4.3.1 Approaches to Learning and Teaching
Broadly speaking, there are three common and intertwined pedagogical approaches to learning and teaching Chemistry:
(1) “Teaching as direct instruction” is perhaps the best-known approach. It has a teacher-centred orientation and requires the teacher to transmit knowledge or skills to the learner. In this approach, teachers assess students’ understanding through questioning, provide opportunities for practice or application, and give assignments for consolidation. A brief lecture can help students to develop their understanding of topics such as the nomenclature of compounds, writing chemical equations or describing the safety aspects of a laboratory experiment. Moreover, a vivid presentation or a good video may convey the key points in a topic effectively in a short period of time. But still, good interaction between
in which learners take responsibility for their own learning. It advocates the use of learning activities such as problem-solving tasks which require various cognitive abilities, and inquiry-based experiments which involve testing hypothesis, designing working procedures, gathering data, performing calculations and drawing conclusions. The Investigative Study in Chemistry discussed in Chapter 2 is an example of how “teaching as inquiry” can be implemented in class.
(3) “Teaching as co-construction” is another important pedagogical approach which involves students and teachers constructing knowledge together. It stresses the value of students sharing their knowledge and generating new knowledge through group work, with teachers providing support as a partner in learning. Students can also work together with other experts to co-construct knowledge. For instance, students might work together on the choice of a site for establishing a chemical plant, and through this develop knowledge and understanding of the issues involved.
These three learning and teaching approaches can be represented as a continuum along which the role of the teacher varies, but is not diminished. For example, a teacher is more of a resource person than an information provider in a co-construction learning process.
Overall, it is important for teachers to adopt a wide variety of learning and teaching strategies and activities to help students attain the various learning targets. Teachers should note that more than one learning target can often be achieved by engaging students in a single learning activity. Learning and teaching activities appropriate for Chemistry are listed in figure 4.1.
Direct instruction Interactive
teaching Individualisation Inquiry Co-construction
Explanation
Demonstration
Video shows
Teacher questioning
Whole-class or group discussion
Visits
The use of IT and multimedia packages
Constructing concept maps
Reading to learn
Information searching
Writing learning journals / note- taking
Problem-solving
Practical work
Scientific investigations
Simulation and modelling
Group discussion
Role play
Debates
Project work
Figure 4.1 Learning and Teaching Activities in Chemistry
As mentioned above, the specific learning targets outlined in Chapter 2 of this Guide can be attained through a variety of approaches to suit the different learning styles of students. The three approaches above are not listed in any order of preference but should be adopted where appropriate.
4.3.2 Variety and Flexibility in Learning and Teaching Activities
This curriculum has an in-built flexibility to cater for the varied interests, abilities and needs of students. Teachers should provide ample opportunities for students to engage in a variety of learning activities to attain the learning targets, with different activities being used to match students’ learning styles.
The learning and teaching activities employed should aim to promote deep learning for understanding, not surface learning of unconnected facts. Deep learning is more likely to be achieved when students are active rather than passive, when ideas are discussed and negotiated with others rather than learned by oneself, and when the content is learned as an integrated whole rather than in small separate parts. In short, activities that encourage meaningful, integrated learning should be used as far as possible.
4.3.3 From Curriculum to Pedagogy: How to Start
Teachers have to make informed decisions on the approaches and activities which are most appropriate for achieving specific learning targets. In the learning of chemistry, activities should be made relevant to daily life wherever possible, so that students experience chemistry as interesting, relevant and important to them.
For example, the following factors should be considered when judging the appropriateness of an inquiry-based experiment in learning and teaching.
• Does the activity address something worth learning?
• Is the topic socially relevant, interesting and motivating?
• Is the cognitive demand appropriate?
• Do students have the required prior knowledge and adequate skills?
• Are resources such as journal articles, reference books, chemicals and apparatus available?
• Is the time available sufficient for the activity?
• Can laboratory supporting staffs help in its implementation?
Listed below are some learning and teaching strategies which can be useful in Chemistry.
They are by no means the only strategies that can be used. It should be noted that learning targets can be achieved using different strategies, depending on students’ strengths and learning styles, teachers’ preferred teaching approaches, and the classroom context.
(1) Constructing concept maps
Concept maps are visual aids to thinking and discussion, and help students to visualise and describe the links between important concepts. They can be used as tools to generate ideas, communicate complex ideas, aid learning by explicitly integrating new and old knowledge and assess understanding or diagnose misconceptions. Students should be encouraged to construct concept maps to review their understanding of a topic, and subsequently refine them in the light of teachers’ comments, peer review and self-evaluation in the course of learning. To familiarise students with this way of representing information, they may first be asked to add the links between concepts or label the links on a partially-prepared concept map. Apart from drawing them by hand, a wide range of software packages for concept mapping is available to enable users to create and revise concept maps easily.
(2) Searching for and presenting information
Searching for and presenting information are important skills in the information era.
Students can gather information from various sources such as books, magazines, scientific publications, newspapers, CD-ROMs and the Internet. Students should not just collect information randomly, but should be required to select, categorise, and analyse it critically, and to present their findings.
(3) Reading to learn
Reading to learn promotes independent learning. In particular, it enables students to understand various aspects of the past, present and possible future developments of chemistry.
Students should be given opportunities to read science articles of appropriate breadth and depth independently. This will develop their ability to read, interpret, analyse and communicate new scientific concepts and ideas.
Meaningful discussions on good science articles among students and with their teachers may be used to co-construct knowledge and to strengthen students’ general communication skills.
The development of the capacity for self-directed learning is invaluable in preparing students to become active lifelong learners.
Articles which emphasise the interconnections between science, technology, society and the environment can enliven the curriculum by bringing in current developments and issues, and so arouse students’ interest in learning. Teachers should select articles suited to the interests and abilities of their students; and students should be encouraged to search for articles themselves from newspapers, science magazines, the Internet and library books.
The main purpose of reading scientific articles is to extend student learning about chemistry.
A wide variety of after-reading activities can be arranged including, for example, simple or open-ended questions to help students relate what they have read to their chemical knowledge.
Students may be asked to write a summary, critique or report on an article, prepare a poster or write a story to demonstrate their understanding. They should also be encouraged to share what they have read with their classmates, either in class or using web-based technologies, in order to cultivate the habit of reading chemistry articles.
Example
In topic XIV “Materials Chemistry”, it is suggested that students should read articles or write essays on the impact of the development of modern materials, such as semiconductors and nanotubes, on daily life. This activity not only helps students to understand the latest developments in chemistry, but also to appreciate that knowledge about bonding is changing dynamically and is revised when new evidence arises, e.g. the discovery of the structure of graphene. This activity also helps teachers to assess what their students have learned.
(4) Discussion
Questioning and discussion in the classroom promote students’ understanding, and help them to develop higher-order thinking skills as well as an active approach to learning. Presenting arguments enables them to develop the following skills: extracting useful information from a variety of sources; organising and presenting ideas in a clear and logical way; thinking critically; and making judgments based on valid arguments.
Teachers must avoid discouraging discussion in the classroom by insisting too much and too soon on the use of objective and formal scientific language. It is vital to accept relevant discussion in the students’ own language during the early stages of chemistry learning, and then move progressively towards more formal and objective scientific language.
Student-centred strategies can be adopted in addressing issues related to science, technology, society and the environment. For example, in topic V, which considers environmental issues related to the use of plastics, teachers can start by raising the issues of domestic waste classification, and plastic waste collection in schools and housing estates. In the discussion, students should be free to express their opinions, and then pool their ideas on why plastic waste should be collected, and the difficulties of putting this into practice. Lastly, students can present their views to the whole class for their classmates and the teacher to comment on.
(5) Practical work
As chemistry is a practical subject, it is essential for students to gain personal experience of science through practical activity and investigation. In the curriculum, the design and performance of experiments are given due emphasis. The experimental techniques for this curriculum are listed in Appendix 2 for reference.
When students have sufficient knowledge and skills related to practical work, teachers are encouraged to progressively introduce manuals or worksheets for experiments with fewer procedural guidelines and ready-made data tables, so as to provide opportunities for students to learn and appreciate the process of science by themselves. In such inquiry-based experiments, students have to design all or part of the experimental procedure, decide on what data to record, and analyse and interpret the data. Because they are in charge of their own learning, students will show more curiosity and a greater sense of responsibility in their work, leading to significant gains in their basic science process skills.
It is better to design experiments to “find out” rather than to “verify”. Teachers should avoid telling students the results before they engage in practical work, and students should try to draw their own conclusions from the experimental results. This helps to consolidate the learning of scientific principles.
Figure 4.2 The Development of Understanding of Scientific Principles through Practical Work
Other than using ordinary apparatus and equipment, teachers may explore the use of microscale equipment to enhance the “hands-on” experience of students in practical work.
With careful design, some teacher demonstrations can be converted to student experiments in microscale practice.
Example
After some practice in volumetric analysis involving acids and alkalis in topic IV, students can be asked to design and carry out an experiment to determine which of the two brands of vinegar is the “best-buy”. The experiment can be carried out using either conventional titration apparatus or microscale chemistry apparatus.
(6) Investigative studies
Investigative studies, which are a powerful strategy for promoting self-directed and self-regulated learning and reflection, enable students to connect knowledge, skills, values
Experiments include
designing and planning
consideration of safety
prediction of results
manipulation of apparatus
collection of data
Conclusions and interpretations include
analysis of experimental results
evaluation of predictions
explanation for deviations from predictions
Scientific principles include
generating patterns and rules from conclusions and interpretations
Stage
Scientific method
and problem-solving Practical Communication Decision- making
Learning and
self-learning Collaboration Analysing the
problem and searching for information
Devising the
scheme of work
Performing the
investigation
Analysing and evaluating results
Reporting the
results
* The skills correspond to the learning targets listed in Chapter 2.
Figure 4.3 Science Process Skills in Investigative Studies
Short and simple investigations can be arranged, preferably from an early stage in the curriculum, to develop the skills required for a complete investigative study. As there are many ways to collect scientific evidence, it is desirable to expose students to different types of chemistry investigation, such as identification of the unknown, quantitative analysis, preparation of substances, making things or developing systems. Through these, students will progress from “cook-book” type experiments to more open-ended investigations which involve finding the answers to questions they have formulated themselves. An Investigative Study in Chemistry can be pitched somewhere between the two extremes of the teacher-directed and student-centred continuum.
Example
A short investigation on the extraction of copper from its ore can be organised after covering the topics “Metals”, “Acids and Bases” and “Redox Reactions, Chemical Cells and Electrolysis”. Students can complete the task either by carbon reduction, or by dissolving the ore in dilute acid and then extracting copper by metal displacement / electrolysis.
A more in-depth version of this investigation may require students to determine the percentage purity of copper and the amount of iron impurity in the copper obtained.
Skills*
(7) Problem-based learning
Problem-based learning (PBL) is an instructional method driven by a problem. PBL is most commonly used in professional courses where students are given real-world problems of the kind they will face at work, but it is being adopted increasingly in many disciplines.
The problems are open-ended, often based on real-life situations and ill-defined with no quick and easy solutions. In the process, students may acquire new knowledge and integrate it with what they have learned previously to solve the problem. Students are required to work in groups to: understand and define the problem; discover what they need to know to tackle it; generate alternatives; develop and test solutions; and justify their suggested solutions. Teachers assume the role of facilitators, resource persons and observers. Students are motivated by being actively engaged in the learning process and taking responsibility for their own learning.
Apart from motivating students to develop a deeper subject understanding, PBL also encourages them to think scientifically, critically and creatively, and to solve problems collaboratively in chemistry-related contexts. Many topics in the curriculum offer rich opportunities for using PBL. Also, problems with different levels of complexity can be given to students, with hints or thought-provoking questions to guide them in their analysis, if necessary.
Example
You are a chemist working for a coffee company. Your company plans to launch the world’s first self-heating can of coffee. You are asked to design the can which can heat the coffee contained in a standard size aluminium can to 60oC within three minutes and maintain the temperature for 30 minutes. The can should be convenient to carry and easy to use, and the coffee is to be served straight out of the can.
The following questions can be raised to help students analyse the problem:
• What is the volume of the coffee the can holds?
• How much heat energy is required to heat up the coffee to the required temperature?
• Which chemicals react to produce a steady supply of heat?
• How much of each chemical should be used?
• Is your product safe for use by customers?
Students can test their proposed solutions to the problem in many ways, such as in a real laboratory or in a virtual environment (e.g. ChemCollective Virtual Laboratory at
(8) Information technology (IT) for interactive learning
IT often provides an interactive environment for learners to take control of the organisation and content of their own learning. With the appropriate use of IT-mediated resources, teachers can enhance students’ understanding of chemistry concepts and processes, and develop their IT skills which are useful for lifelong learning.
There are numerous and growing opportunities to use IT in learning chemistry. If appropriately used, it can enrich the learning experience. The following are some examples for illustration:
Examples
• Three-dimensional computer images can be used to illustrate the shapes of molecules, the concept of chirality and the chemical structures of crystals, polymers, etc. These computer images can be manipulated as if one was examining a real model.
• Animations can help students to visualise abstract chemistry concepts and processes, especially in the microscopic world, e.g. reactions in chemical cells.
• Digitised videos are particularly useful to stimulate the interest of students and give them some experiences of the world outside school for example, industrial processes in the extraction of metals and refining of crude oil, and the use of modern chemical techniques in chemical analysis. In addition, digitised videos can be used to show experiments which are difficult or dangerous to conduct in school laboratories. They also allow students to review observations and laboratory techniques of chemistry experiments without actually repeating them.
• Computer simulations can be used to model a reversible reaction at equilibrium, the factors affecting rate of reaction and the processes of a chemical plant. Students can carry out a number of virtual experiments safely and quickly to discover the relationship between different variables of a chemical system. They can learn from their mistakes without paying the price of real errors.
• Spreadsheets can be used in analysing and plotting experimental data, and also for the modelling of chemical systems, thus allowing students to explore “what-if” situations.
This helps to move students’ understanding beyond repetitive calculations and the plotting of numerical results.
• Data-loggers (or appropriate single-board computer) and sensors are particularly useful for experiments which involve very rapidly changing data, are very lengthy or have to capture multiple sets of data simultaneously. For instance, they can be used to study the rate of reaction. The software accompanying a data-logger can generate graphical representations of the data immediately so that students have more time to analyse, discuss and evaluate experimental results right after the runs.
• The Internet allows students to go beyond textbooks and find current and authentic information to help them understand concepts, construct knowledge, and observe and explore the world outside school.
• Communication tools (synchronous and asynchronous) and web-based collaborative knowledge-building platforms can facilitate interaction and dialogue among students, which promotes knowledge sharing and construction. More knowledgeable participants can act as teachers as well as learners.
• Online assessment tools can provide instant feedback to teachers and students. The functions for tracking the answers of individual students can give teachers information on students’ understanding of concepts which may help them to identify students’
misconceptions and learning difficulties.
• Interactive computer-aided learning resources can enhance the active participation of students in the learning process. Since Internet access is widespread, students can easily get access to web-based learning resources anywhere and at any time.
(9) Providing life-wide learning opportunities
As learning can take place anywhere in the community, not just in the classroom or school environment, it is essential to provide out-of-school learning experiences for students.
Life-wide learning opportunities can increase students’ exposure to the real scientific world.
Examples of appropriate learning programmes include popular science lectures, debates and forums, field studies, visits, invention activities, science competitions, science projects and science exhibitions. These programmes can also offer challenging learning opportunities for students with outstanding ability or a strong interest in science. The STSE connections described in Chapter 2 of this Guide are a good reference for organising life-wide learning experiences.