The marvellous world of chemical compounds

Hanza George, Mursaleen Shaikh and Savita Ladage

“Do we teach biology, chemistry, physics, mathematics, or do we teach young people how to cope with their own world?” asks Gerard Fourez, in his 1997 paper titled Scientific and Technological Literacy as a Social Practice, published in the Social Studies of Science journal. In his opinion, if we want students to remain engaged in learning science, the goals of science education should not predominantly focus on producing specialists in a particular subject but on much broader aspects.   

In the Indian context, at the primary and middle school levels, efforts are being undertaken to correlate scientific concepts acquired in school to the learners’ surroundings and daily life experiences. The secondary and higher secondary stages are crucial as students start forming their impression about domains of science through deeper engagement with its content. However, at the secondary level, where domain-specific theories and scientific facts become more central, science as a subject loses its connection to daily life and is further fragmented as physics, chemistry and biology. Teaching students, specific subjects in-depth is important for developing competencies in a particular field. However, at the same time, complete disengagement with aspects such as interconnections among science domains and everyday life, its impact on society and awareness of societal requirements which gave rise to certain fields in science, etc., is not desirable as it is likely to hinder the development of holistic perspectives regarding domains of science.

Chemistry is one of the domains which is substantially delinked from everyday life when it is taught in formal schools. The chemistry textbooks at the secondary level are often abstract in nature with the introduction of several theoretical concepts/models soon after the subject is introduced to students. Due to fear of students handling chemicals, limited opportunities are provided to the students for exploring experimental activities and materials in chemistry. The information presented about compounds also becomes a burden as often the emphasis is on making students memorize chemical facts about the compounds and not on enhancing learner experiences about the same. For all these reasons, students perceive chemistry as an alienated abstract domain, chemicals as materials available only in school laboratories and do not understand the relevance of chemistry to their lives.  

To address the issues described above, we in the chemistry group, Homi Bhabha Centre for Science Education (HBCSE), Tata Institute of Fundamental Research (TIFR), are preparing materials in the form of leaflets about some of the interesting chemical compounds and highlighting their connections to our lives. Through these leaflets, we attempt to help the learners look at chemical compounds through multiple lenses like history, art, trade, and its interconnections with society, along with the chemistry content. Even though we have designed the leaflets for learners studying chemistry at secondary and higher secondary levels, these leaflets are useful resources for any individual interested in chemical compounds.

In the following section, we have taken the example of the compound Indigotin (compound present predominantly in Indigo dye) to elaborate the different aspects that are highlighted in the leaflets.

The first section of all the leaflets presents information about the main natural sources of the compound, its structure and properties like melting or boiling point. Looking at the structure, one gets to know the elements present in the compound, their linkages with one another, the overall molecular formula and the mass of the compound. Students at the higher secondary level can also identify the functional group(s) present in the compound, which often helps in predicting the prototypical reactions the molecule is likely to undergo.

You will find sections titled “Do you know?” at various places in the leaflet. The purpose is to highlight some of the important, interesting and also lesser-known facts about the compound.

The next aspect covered as a part of the leaflet is traditional and/or modern methods of production. Both the Industrial/ laboratory methods of synthesis are described. For naturally occurring compounds, we have included a section on the extraction process from the sources. Knowledge of the production at the industrial level is important as often such details are not known to students. On the other hand, the laboratory method helps to understand the important experimental conditions such as the variables that affect the yield of the product. If used effectively, one can compare various methods of laboratory synthesis and develop first-hand experiences about which routes are better and effective for synthesis. A particular method is chosen depending upon its use afterwards, the level of purity desired and also how benign the reaction conditions are.

Almost all the leaflets have information on history, culture, art, tradition. The Indigo revolt has been studied by students at the school level, as part of their history subject and thus, they can correlate  the historical relevance with the compound. As explained earlier, along with chemical aspects, such aspects will be useful in generating a broader perspective about the compounds and chemistry in general.   

Equally important are interesting applications of that compound. For instance, Indigo dye is used for dying fabrics such as jeans. Efforts are made to present the chemical aspects of such applications in lucid language. We hope readers will get glimpses about how chemistry works in a given application. We are translating these leaflets in Hindi and Marathi so that they reach a wider audience.

Another purpose of these leaflets is to motivate readers to read further about various aspects covered in the leaflets. So, towards the end of the leaflets, you find references that are used for preparing these leaflets. Most of these references are available publicly on the internet. Additional references are given in the section called References and Further Readings. We have included yet another feature in these leaflets which will motivate the learners to read more about interesting aspects of these compounds, that is, few interesting questions to which the answers are not provided.

Interesting long questions about the chemistry of some of these compounds (eg. Geosmin, a major component of mitti ka Ittar, is the compound responsible for the distinct fragrance produced when the first rain falls on soil) have been covered as part of the Indian National Chemistry Olympiad examinations (INChO- round 2). Any student studying chemistry at the higher secondary level or undergraduate level and chemistry teachers teaching at these levels can visit such questions as they are available in the public domain (https://olympiads.hbcse.tifr.res.in/how-to-prepare/past-papers/).  

Currently, these leaflets are in read-only format. We will improve them with feedback received from readers. In the near future, these leaflets will be available in printable form. At present, the compounds covered are:

  • Alizarin – A red dye extracted from the roots of Madder trees
  • Betanin- A red food colour obtained from beetroots
  • Citric acid- A flavouring agent which is commonly present in citrus fruits
  • Curcumin- A compound that is responsible for the distinct colour and flavour of Turmeric
  • Ethephon- A plant growth regulator
  • Geosmin- A compound predominantly responsible for the aroma of wet soil
  • Indigotin- A blue dye, naturally prepared using Indigo plant leaves
  • Lawsone- A compound present in Henna leaves/Mehendi
  • Para-phenylene diamine (PPD)- A compound commonly found in chemical hair dyes/colours

To access the leaflets, visit the following link – https://chem.hbcse.tifr.res.in/resources/leaflets-of-compounds/

We hope you will enjoy reading them and get motivated to read such aspects about the compounds. In our opinion, it will help readers start appreciating chemicals and understand their significance in our lives.

Acknowledgements: We are thankful to Shreyank Mandavkar and Krupa Subramanian who are authors for some of the leaflets mentioned above. Besides, Drs. Ankush Gupta and Indrani Das (Sen), members of chemistry groups at HBCSE have continuously supported and provided valuable inputs for the development of each of the leaflets. We express our gratitude towards Profs. Srinivas Samant, Gulshanara Shaikh and Amar Srivastava for critical reviews of the leaflets, especially the translated Marathi and Hindi versions.

We acknowledge the support of the Department of Atomic Energy, Govt. Of India, under Project Identification No. RTI4001.

The authors are with the Homi Bhabha Centre for Science Education (HBCSE), Tata Institute of Fundamental Research (TIFR), Mumbai. They can be reached at [email protected], [email protected] and [email protected] respectively.

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