Green chemistry

Dr. Sneha & Dr. Vishwanath Gogte

Science is one of those subjects that offers tremendous scope to make learning experiential. This article explains how chemistry can be taught while engaging the students in agriculture. Chemistry is rightly called the mother of all sciences. This is one subject that cannot be ignored by students of any discipline. Yet, a large number of students find chemistry difficult to understand and lose interest in it. Some of the reasons given are: too many names, symbols and formulae to remember, complicated equations and reactions, disconnect between reactions learnt in the classroom and day-to-day situations, inaccessibility of lab equipment and facility to gain experiential learning, safety issues. Rote learning and an exam-oriented approach are other reasons for the lack of interest in the subject.

Work centric learning engages each student in an authentic activity as an individual and in a group. Every activity is result oriented and students perform, observe and analyze every step of the activities. Each activity is also linked to their day-to-day conditions and at each point relevant concepts in science can be discussed.

When engaged in agriculture students had to learn about the formation of soil, its composition, the different types, properties, methods of plantation, the alternatives to soil, methods of irrigation, harvesting, etc.

We discuss here our observations based on year-long activities involving about 200 students of classes 6th to 9th. Work centric learning is essentially a problem based method and each activity has a pre-determined authentic goal. This authenticity ensures a meaningful involvement of each child in the learning process. Therefore, the students had opportunities to hypothesize, experiment, observe, and evaluate their work. Since the activities were field based there was a sense of joy and liberation from the rigid classroom boundaries. This ensured total involvement of the students in the learning process. The work involved team work, promoting collaboration and ample communication and social skills. It also promoted an open and continuous dialogue between the teachers and the taught. Integration of the activities with the curricular subjects strengthened conceptual learning. Constant and close interaction and collaboration with the corresponding subject teachers ensured a seamless blend in classroom and field-based education. The entire exercise promoted cognitive, psychomotor, and emotive learning domains of the intellect.

BOX: Activities you can do

Winogradsky’s Column is an excellent activity, to demonstrate the growth of micro-organisms. As a result of this activity, students will:
• learn about the metabolic diversity of prokaryotes, applying terms such as phototroph, chemotroph, autotroph, and heterotroph.
• observe the cycling of mineral elements in natural environments, particularly sulfur.
• discover how microbes occupy a highly specific niche depending on environmental tolerance and energy requirements.

Building a Winogradsky Column is both inexpensive and effective, offering students a memorable hands-on experience.

To incorporate it into your classroom, you should allow about 3 months to see observable growth patterns.

The resources below will help you get started. Have fun in the mud.
Requirements:
• Glass jar
• Soil
• Pond water
• Gypsum
• Calcium carbonate

Protocol

• A tall glass jar is taken and one third of the jar at base is filled with shredded filter paper.
• The second layer in the jar contains soil/mud and 1.5 grams of gypsum and calcium carbonate each mixed together so as to form a homogenous mixture.
• The third layer is water. The water used is from pond/lake/river.
• The upper one-third of the jar is left empty.
• The jar is covered with black paper and incubated for two to three weeks.
• The black paper is removed and now the jar is incubated under sunlight for a few more weeks.
• Observe the chemical, microscopic, and colour changes every week.

Dr. Vishwanath Gogte is passionate about education and has established Discovery Science Exploratory, a mobile science and skills lab for schools since 2004 that goes to both government and private school for hands on learning. He can be reached at drvbgogte@gmail.com.