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Chemistry is vital and chemistry is life

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January 14, 2017

Chemistry is vital and chemistry is life

Chemistry is the study of ‘the knowledge of the natural world’. The separation of the natural sciences into physics and chemistry divides a larger body of knowledge into more manageable branches. But the concepts, techniques and applications of the various sciences are interdependent. Most students wish to pursue the principles and applications of chemistry as a foundation for their specialty.

Chemistry has grown as a discipline during the last 250 years. In chemistry, there is a huge body of theories, facts, knowledge and applications already worked out. Thousands of new compounds are made annually and lakhs of entries are reported in chemical literature every year. The vast number of products of chemistry is not only seen in pharmacy but in every aspect of our daily life. The products of the study of chemistry are inseparable from our lives and the things which we use from the start of the day till the end involve chemistry.

The following story attempts to show the importance of chemistry in our everyday life.

Risheeta Madireddi is a student of class X. She is called Rishi by her parents and friends. Rishi is an active, smart and multitalented girl. On her birthday, she woke up early at 5.30am to get ready for school. She quickly wore her slippers to rush to the restroom (Slippers are made of materials like rubber, velvet, cotton, wool, elastic or leather with some design on it. These materials are insulators, durable and light in weight. They are made of long chain of polymers which are resistant to heat and current; they can be natural or synthetic products). She picked up her tooth brush and applied paste on it to brush her teeth for good oral hygiene (tooth brush handles are made of plastic, containing long chain of polymers and bristles are made of synthetic fibres such as nylon. Both the products are light, durable and do not absorb water. The recently produced electric tooth brushes contain tiny rechargeable batteries and an electric surface board. Tooth pastes are made of mild bases, so that the medium in the mouth becomes basic which can neutralise the acids released by the bacteria.

These bacteria grow due to food left over between the teeth. Hence, it is good to brush morning and night before going to bed to protect our teeth from decay. A variety of toothpastes are available in the market for anti-cavity, extra whitening, etc. with varied compositions – basic abrasives to scour off bacteria films, fluorides to harden teeth against decay, strong flavour to hide bad odour are some of the varieties in toothpastes). She switched on the geyser to have a hot water bath (electric switches are made of bakelite plastic, which is thermosetting plastic (insulator) and can be moulded only once. Bakelite is made by mixing phenol and formaldehyde and heated strongly. It is widely used in preparing switches, handles of cookers, body of phones, etc due to its toughness and insulation property). Coils of geysers are made of alloys (mixture of metals or metals and nonmetals) but not pure metals as they require current and not melt or get burnt when excess current flows due to their high resistance compared to pure metals. The function of a water heater is to convert electric energy to heat with the help of coils. The thermostat present inside the geyser controls the temperature of water and does not allow the temperature of water to rise more than a certain level).

Rishi uses soap and shampoo to clean her body (soaps are sodium salts of higher fatty acids, which are manufactured by mixing sodium hydroxide – NaOH- with oils like sandal wood or rose or milk cream, etc and also ethanol and some common salt – NaCl). Detergents and shampoos also have similar composition but stronger than body soaps. Detergents are made of strong synthetic petroleum products like salts of benzene sulphonic acids. The soap molecules contain an ionic part to remove water soluble dirt from the body and an organic (hydrophobic) end to remove oil dirt from the body.

Rishi wears her white school uniform made of polycot fabric (mixture of polyester and cotton) and stockings with shoes.(Different variety of fabrics are used in manufacturing uniforms like cotton mixed with polyester, terry cotton, polyester viscose, etc. These are mostly mixture of natural and synthetic fibres, having features like anti-pilling, shrinkage control, colour fastness, stain resistant finish, durability, etc. Stockings are made of nylon, a synthetic fabric made from petroleum products. Nylon is light weight, has incredible tensile strength, durable and takes dye easily. Nylon is widely used to manufacture stockings, bags, ropes, dress materials, etc. Nylon has many varieties, Nylon6, is made by the condensation and polymerisation of two materials Adipic acid and Hexa methylene diamine. Shoes are made from a combination of materials. The sole has 3 layers – insole is made of a thin layer of synthetic ethylene vinyl acetate; mid sole is for cushioning made of polyurethane and outer sole is made of carbon rubber and these may differ from company to company. The rest of the covering is made of leather or nylon overlay with laces made of cloth.)

Rishi’s mother and father, Radhika and Ravi wish her a happy birthday and they have breakfast together. Radhika serves Rishi with bread, fruit jam and warm milk (milk obtained from the cattle is cooled to 7 degree celsius within two hours of milking. The collected milk is tested for antibiotics before taking it to the processing plant. If no evidence of antibiotics is seen, the milk is subjected to pasteurisation – heating milk to a temperature of 60 degree celsius and cooling to kill the germs). It is then sold as whole milk. If cheese is removed from the milk by centrifugation, the milk is then sold as toned milk. Various milk and milk products sold in the market involve many chemical processes. The preparation of bread involves mixing of wheat flour, salt, water and yeast. The mixture is kneaded into a soft mass, cut in to required shapes and heated strongly. The yeast present in the dough releases carbon dioxide gas and makes the bread spongy or fluffy. Jams or jellies are prepared from fruit. Fruits are cut, boiled and filtered and the thick syrup is added with sugar or pectin and boiled again. Vinegar or vitamin C is added as a preservative. These processes result in plasmolysis of cells of fruit and the preservatives added prevent spoiling of food.

Rishi carries her school bag (made of nylon), with lunch box, water bottle (made of polythene) and rushes to board the school bus. (Polythene or polyethylene is an important plastic, manufactured in different forms to pack foods like milk, cold drinks and water and has many more uses like manufacture of boxes, toys, pipes, furniture, etc. Plastic has become inseparable from our lives due to its many advantages but the great disadvantage of it is its non biodegradable nature. Polythene is produced in three main forms – low density (LDPE), linear low density (LCDPE) and high density (HDPE). LDPE or LLDPE is preferred for film packaging, for electrical insulation, buckets, food boxes, squeezable bottles, etc. HDPE is used to make containers for industries, pipes, etc.). Though Rishi’s father and mother have a car each, Rishi uses the school bus, to save fuel and also reduce pollution (school buses are generally painted yellow, as it gets your attention faster than any other colour. Compared to any other colour, lateral peripheral vision for detecting yellow is 1 to 24 times greater than for red. Diesel is used as fuel in heavy vehicles like buses, trucks, etc. Diesel is composed of about 75% saturated hydrocarbons and 25% aromatic hydrocarbons. The chemical formula of diesel ranges from C10H20 to C15H28. It is manufactured by the fractional distillation of crude oil. Compared to petrol, diesel gives higher power (1.5 litres) and is less volatile than petrol but diesel gives more carbon dioxide emission.

Rishi reaches her school and attends school assembly. She donates a plant to the school and plants it in the school garden as it was her birthday and later distributes chocolates to her class-mates (chocolate is the product of a long complicated refining process and is obtained from bean pods of the ‘the obroma cacao’ tree, which means ‘food of the gods’. These trees grow in temperatures within 20 degrees celsius. Chocolate preparation begins with the harvest of the cacao pods. The pods are split to separate beans and pulp and allowed to ferment for 2 to 8 days. After fermentation, the beans are spread to dry and packed to prepare chocolates. In factories, beans are roasted and transferred to a winnower to separate shells and nibs of beans. These nibs are ground to a thick rich paste called chocolate liquor which is foundation for all chocolate products).

Rishi gets busy with her classes reading books and writing notes (paper is made from a variety of materials like wood pulp, rice, cotton, old clothes, etc. Today paper mainly comes from wood logs and recycled paper products. Much of the paper we use is a blend of new and recycled fibre. Ink is a liquid or paste that contains dyes and is used to colour a surface to write text or design. Ink was first used by Egyptians around 4000 years ago and ink is widely used every day by students, teachers, writers, etc. Many varieties are available in the market. The basic dye material is obtained from plants or animals or minerals like graphite.)

Rishi completes all her classes and the last class is sports period. She takes a basket ball to play with her friends in the play ground. (Basket ball is made of composite leather, a synthetic material designed to withstand slam dunks and have good grip. Leather and rubber balls are also made which are more durable .Beneath the surface, basket ball has a grid work of nylon and butyl material which help the ball stand up to hours of double dribbles.)

Rishi reaches home, completes her home work quickly and gets ready for the birthday party. All her friends reach on time and she blows the candles and cuts the cake. Rishi’s parents serve snacks and soft drinks to all the guests (the chemistry of cake involves mixing of flour, eggs, sugar, butter and baking powder. The mixture is heated strongly at appropriate temperature and time. Flour provides the structure, eggs bind the ingredients, butter tenderizes, sugar sweetens and baking powder (a mixture of baking soda and tartaric acid) reacts on heating to release carbon dioxide and gives sponginess to the cake. Candles -manufacture of candles involves 3 steps -making the wick, the cotton or linen wicks are braided and treated with chemicals so that they bend at 90 degree angle while burning. Wax is obtained from paraffin wax (product of fractional distillation of crude oil) is heated and melted, filtered and added with dyes or perfumes. Finally, moulding of the candle involves pouring molten wax in to desired shape trays and wick is passed through the material and cooled).

Rishi is happy with her parents and friends at the birthday party. When all her friends leave, she feels tired and says good night to Mom and Dad. She goes to her room and switches off the tube light to sleep.(Tube lights consist of a long glass gas discharge tube and the inner surface is coated with phosphorus; the tube is filled with an inert gas like argon. The tube is sealed at low pressure with two filament electrodes at both ends. The current supplied heats the electrodes and gas, which emits light)

Rishi goes into deep sleep with sweet dreams, which too involve some bio-chemical processes happening inside the body. All the life processes like respiration, digestion, excretion, etc involve bio-chemical reactions.

Thus, all the objects we see around us, all the living organisms (plants and animals) we observe, are the products of chemistry and only chemistry.

(An attempt has been made to know the chemistry behind a few things in our daily lives in the form of a story)

Surekha Nayani

Surekha Nayani

Surekha Nayani, M.Sc (Chemistry),B.Ed has fifteen years of teaching experience in CBSE schools and has been teaching Physics and Chemistry to secondary school students.

Presently, she is working as Head of the Department of Science and also as CBSE Co-ordinator in Delhi Public School, Nacharam, Hyderabad. As HOD she trains teachers in teaching-learning processes like developing and presentation of content, preparation of worksheets and question papers, designing CCE etc. and also conducts workshops on various aspects of teaching science.

She has written articles on teaching science by focusing on creative methodologies which arouse interest in the subject. She strongly believes that every teacher should emphasise proper planning, preparation and effective presentation of subject matter, every day and in every class with commitment which influences and empowers student learning.

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