How to make Chemistry lab an efficient place of learning while working

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How to make Chemistry lab an efficient place of learning while working?

Manisha Jain| and Neeti Misra

Acharya Narendra Dev College (University of Delhi), Kalkaji, New Delhi – 110019, INDIA.

Contents

Abstract

Chemistry experiments have been used by magicians to attract common man’s interest because of their instantaneous results (generally) appearing like magic. However the similar experiments performed in the lab as a regular class exercise fails to attract the students. Are we, the Chemists, losing our ability to make the students understand the magic of chemistry? The given survey provides an overview of the present status of chemistry lab education at tertiary level, its benefits till date and shortcomings leading to lack of interest in the subject observed in the present generation of students. The authors after an extensive literature survey and their personal experiences have come up with many suggestions that can again make chemistry lab and experimentation fascinating for undergraduate chemistry students. The ideas so suggested may well be known to most of the teachers but they have not been universally practiced or the infrastructural limitations have restricted their adoption. The authors have tried to present a concise collection of all the possible approaches that are scattered in the literature or which are not so commonly used. The main highlights of the study are: Analysis of conventional laboratory systems - both advantages and shortcomings, improvement in existing approach to make it live again within existing infrastructural limitations, Introduction of innovative methods in laboratory work - different methods, requirements for inclusion of innovation, positive outcomes of such innovations (both from student as well as teacher’s point of view). Some of the approaches have already been practiced by the authors with positive results.

Introduction

Chemistry has long been a fascinating branch of science. Chemical reactions have always been looked upon as mystery and have often been employed by trickers and magicians to make money. Every single phenomenon occurring in our body or in our surroundings or elsewhere in universe involves chemistry. Chemistry is the science of day today life and this would be equally true if we say’ chemistry is the life of day today science. Whether it is the process of seeing or breathing, eating or sleeping, thinking or talking, every act of ours involves chemical reactions. The mystery of chemistry has always encouraged researchers to explore in this field. The chemistry teaching is always enjoying because of the possibility of practical demonstrations of the subject. The chemistry labs provide an excellent opportunity to understand the variety of processes. This branch of science has therefore been introduced as a basic subject right from the primary schools and gains importance with increasing maturity level of students. Inspite of a wide applicability of this branch of science, the chemistry as a subject of choice for undergraduate studies is losing its charm. Are we, the chemists, losing our ability to make students understand the magic of chemistry? The present article is an overview on the present miserable state of chemistry lab education at tertiary level, its benefits till date and shortcomings leading to lack of interest in the subject, in the present generation of students.

Aim of lab schedule in science courses

The main aim of introducing a lab schedule in regular teaching is to develop an understanding for the concepts taught in class lecture, by performing the experiments and self elucidation of the results. By this exercise the subject appears to be more real as the student self experiences the concepts experimentally. This helps in developing the observational and manipulative skills of the student resulting in a better understanding of theory.

The lab course is generally designed in a manner so that class room teaching is immediately recalled in lab. This has been the approach till date and Conventional Chemistry labs follow the same method. However the same approach is now having less impact on chemistry learning. The flaws in this conventional teaching are clearly visible. The connectivity between lectures and lab work is rarely brought to the notice of the student. The lab instructions are generally mechanical involving step by step instructions of age old procedures. The conventional chemistry lab instructions are generally expository where both teacher and students are aware of the outcomes of the experiments. The practical approach to the subject thus becomes a spoon feeding approach, where the student works mechanically following a given procedure, with an aim of getting a set result. The lab work thus becomes more result oriented with almost no emphasis on conceptual understanding. Words like ‘why’ and ‘how’ have lost their significance in performing experiments. Very few students make their effort to understand what is actually happening in any reaction they are performing. Somewhere our education system at present is responsible for the pathetic situation of this so real subject. The lab schedules are tight, restricted to fixed time. The facilities in the lab per student are minimal and the lab work evaluation is based more on manipulative skills than on interpretational skills of a student. Often scarcity of instruments in the lab results in lack of interest in students as they have to wait too long for their turn to get the instrument. The advance knowledge of the results of the experiment make student less honest in his practical hand as he generally ends up in cooking the data with a fear of getting his file red marked. A greater emphasis is put on getting accurate results ignoring the precision. Thus a student wastes a lot of time in getting correct results without even realizing why the results are not correct. His interpretational skills, if not encouraged, would come to a halt in this situation. Students who lack the requisite theoretical framework for performing the experiments, for collecting the data, will not know where to look or how to look in order to make appropriate observations for the success of the experiment. These expository types of lab instructions were useful in developing the hand on skills of a student and serve no other purpose. These might have not been taken seriously earlier in the lack of competition and hence less application of the subject studied. However in today’s competitive world, and ongoing research in the chemistry and related areas, lab skills are gaining significance. Such conventional labs have been continued till date because this result in efficient management of a large group of students in fixed time schedule as everyone has to do same exercise with same instructions and thus less chaos in lab without bothering teachers. However this has even more disastrous consequences – continuous loss of interest of students in experimental work as this promotes mass copying of observations where each student is expected to come with same result. This leaves no room for planning of experiments and hence innovations.

What to do now?

Should we continue following the same style of lab teaching or does it require some improvements?

Present status of universities to every chemistry teacher in form of declining strength of chemistry graduates every year followed by even lesser number of skilled chemists. Is this situation not an alarming one? In this fast changing world, why not education system also modified? The reputation of Chemists is at stake now? How to energise this subject again? Here are some of the suggestions known to everyone but not widely practiced:

Some solutions...

How to make lab experimentation an enjoying experience?

Conventional Labs

Conventional lab practice can be improved within infrastructural limitations by:

  1. Encouraging the students to first correlate the experiment with whatever little they have studied in theory. They should develop an understanding for why a particular experiment is being performed? How is it going to help him? Is it a verification of the concept he has already studied or is it something new he is going to do and deduce?
  2. Making students understand that inspite of its magical results, chemistry experiments are not magic. Students should be prepared to get erratic results also and should be able to interpret them.
  3. Motivating students to first find out the result for the experiment on his own and then to compare it with standard result. Any discrepancy will then encourage him to look out for all possible sources of error in the same exercise done by the whole class.
  4. Crossing time barrier whenever possible will give a student more freedom and opportunity to explore the different aspects of the regular class exercise or to rectify his mistakes in the experiment once sources of the errors are clear to him.
  5. Listening to student’s complaints has a great impact on student. If the instructor ignores the problems a student faces in lab because of administrative reasons or else, the student starts becoming reluctant to discuss any matter regarding work with him. This results in loss of probably an efficient future chemist. The teacher should listen to student’s problems and try to make him comfortable to lab environment by working out a solution for his problems.
  6. Correlating the experimental work with real world apart from classroom teaching will help the student understand the purpose of studying the subject. It will make him think more real.
  7. Making students aware of the safety norms while working in labs. This will make them more responsible towards their acts and hence a respect for the subject they are studying.
  8. Emphasizing more on precision of the observations than on the accuracy of results. The student’s ability to reproduce the observations should be encouraged. If he fails to reproduce them, he should be encouraged to enquire for probable causes for discrepancy.
  9. Evaluating student’s performance in lab on the basis of his interpretational skills along with manipulative and observational skills.
  10. Decreasing distance between students and teacher by involvement of teacher in bench work to demonstrate the correct procedure say for handling a burette or in judging the endpoint in a titration or in making a dye etc. This will make lab environment friendly, immediately easing out the tension among students while working in front of instructor.

Innovations

Apart from these improvements in conventional lab practice, some innovations can also be introduced which will result in making labs more attractive.

Innovative Approach to chemistry labs:

  1. Submission of lab work reports in the form of posters, occasionally or frequently, in place of formal record books. In the traditional recording, a student concentrates too much on unnecessary procedural details rather than on interpretation of results. The poster encourages the creativity of the student, helping him to come up with a clear and precise presentation of the data and results.
  2. Discussion of results of class experiment by each student in front of the classmates (with the help of posters or slide presentation using OHP or computer). This will give an opportunity to face a large number of audience each having an understanding of the subject and capable of participating in discussion. Such practice will increase the communication skill of the student in the subject being talked about, will develop a quality of quickly analyzing a problem (in the form of question raised) and responding it with full conscience.
  3. Evaluation by peer group – This serves double purpose. A student feels more secure with no biased evaluation from teacher (This is a normal complaint of most of the students). Secondly when a student evaluates other student’s work, he ends up in developing an entirely different but improved understanding of the same experiment done by him. This evaluation however in the end should be reviewed and discussed by the Teacher in the class.
  4. Introducing new concepts of lab:
    1. Interdisciplinary Approach: The lab course should be designed keeping in mind the links and applications of subject. Chemistry is not an isolated subject but lies at the heart of most other branches of science be it life science or physical science, analytical science or material science. Such correlation should be brought to the notice of student right from the beginning and should be reflected in practical work. A student should develop an understanding for the utility of experiment done in chemistry lab in other fields also, Taking an example of chromatography technique, taught in first year of various undergraduate studies. The technique can appear significant to chemistry students if it involves separation of a mixture of cations or a mixture of simple organic compounds. At the same time it will appear fascinating to life sciences students if it involves separation of various components of plant extracts. Similarly an experiment involving measurement of optical rotation wll be immediately recognized by chemistry students as related to stereochemistry appearing useful at the same time for physics students. The experiments should be so designed so that they can incorporate a bit of exercise from different streams e.g; Estimation of copper in a copper complex involves an understanding of coordination chemistry during synthesis of complex and principles of analytical chemistry (Gravimetry and colorimetry) during analysis.
    2. Collaborative approach:

In such type of approach, innovation is brought about by dividing one experiment into a number of parts and each group of students is assigned different task of same experiment. Say for example, preparation and separation of a mixture of ortho and para nitroaniline (or any such pair) through column chromatography. Experiment can be divided into three prts – synthesis, separation and analysis – and hence each task assigned to three different groups. One group of students can synthesise the sample (mixture of ortho and para nitro aniline) and the crude product obtained can be passed on to the second group for separation of ortho and para products. The extracts of column chromatography can be passed onto the third group to recover the compounds and check their melting points and other properties. Such exercises result in good team spirit among students, helps in understanding the importance and accuracy of each step in any experiment, sense of responsibility for performing any experiment and time management skills.

This new type of approach also makes students more responsible for their lab performance. In such type of labs, the results obtained from experiment performed by students in one lab are utilized by students of other lab to perform a new experiment which is based on results of first lab. For an example, the Chemistry lab and Analytical lab can be coordinated in this way: Chemistry students can synthesise one particular compound, purify it to their best and furnish these samples for analytical lab where analytical students can make an analysis of any property (e.g; purity, max, optical rotation, melting point etc.) of the synthesized compound. This way students of chemistry will have a sense of responsibility as they know that their results form the basis of experiments of other lab. Similarly analytical students will develop a sense of relying on other’s data – an approach adopted in corporate world. Similarly chemistry lab and life sciences lab can be collaborated where life sciences lab can provide with DNA isolated from various plant tissues and chemistry students can identify it or analytical students can analyse it for its molecular weight.

In this type of approach, the same traditional experiments can be asked to perform by the whole class with a difference, that no step by step instructions are given. They have undetermined outcomes and require the students to formulate their own procedures. Since no specific directions are given to students, students are free to workout any procedure (with prior discussion with teacher), feels more responsible in laboratories, develop planning skills for experiments and while outlining their own procedures, understand the purpose of investigating a problem and interpretation of results. However these type of labs are associated with one drawback – students take much more time in doing an exercise than in conventional labs and can formulate only those procedures which are not elaborate or which does not involve much instrumentation. The technique however can be applied in the form of assignments of short terminal or yearly projects, where students are encouraged to draw knowledge from class lectures and apply in designing an experiment or solving a problem.

Requisites for successful implementation of Innovation in Chemistry labs

  1. Interlaboratory collaboration or Interdisciplinary experiments require more forethought and planning by Teachers.
  2. The skill level of various students should be kept in mind while designing an experiment.
  3. Evaluation of student should be based on his interpretational skill and not only on his data recording in conventional labs.
  4. Teachers should be willing to devote extra time to students who wish to learn more.
  5. Patience, good listening ability, unbiased attention and judgment is required from teachers.

Benefits of implementing innovation in lab

Development of manipulative and interpretational skills of a student, critical thinking, problem solving, time and resource management skills, increased confidence and sense of accomplishment in students, development of scientific attitude.

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