Thursday, October 22, 2015

Engaging Indian school students in real science experiments

Science education in schools in the Majority World faces many challenges including lack of resources, poorly trained teachers, and a fixation on rote learning from text books. Even at “good” schools few students rarely ever do experiments or hands on demonstrations. The focus is on preparing standard answers for exam questions.

One recent big change in school education in the Majority World is the proliferation of low-cost private schools, even in extremely poor communities. Most of these are English medium. A recent cover story in The Economist chronicled this development.

While in India, I enjoy reading The Hindu newspaper each day. I think the quality of journalism and the substance of the issues covered is much higher than most Western newspapers. More than once a week there is an op-ed piece or article about the problems with Indian school education. Topics covered include the stifling of critical and creative thinking, the lack of autonomy given to teachers by all knowing and controlling principals, …

The last two saturday mornings my wife and I have visited a small private school to give a science lesson for about 2 hours. This school is run by a Charitable Trust. It has a couple of hundred students. A significant fraction are orphans (biological or economic) who live in a children's home also run by the Trust. Annual school fees are about 15,000 Rupees (roughly US$300) including uniform and textbooks. This covers less than half the actual cost; the rest is made up by private donations. Particularly poor students receive scholarships or fee relief. Unlike some Indian private schools this one does not expel students who do poorly on exams. (Schools do this so they can boost their average exam performance). Our personal connection with the school is that the Trust is connected to the church we attend in Bangalore. Both of our own adult children have volunteered at the school and children's home.

Here is roughly what I did in the science lesson. One week we had year 9 (called 9th standard in India) and the next week year 10.

The main goal is give a hands on experience that will help the students see that what they read in the textbook or memorise for the exam actually has something to do with the real world.
It is centred around a baking soda and vinegar film canister rocket. Since this involves cheap household chemicals the hope is the children and/or their teachers might do it again.

I begin with a brief discussion of the scientific "method": ask a question, make a hypothesis (a big idea), design an experiment, make measurements, record data, analysis data, conclusion, and communicate results. I then illustrate this by sticking a wooden skewer in a balloon then show how you can actually put the skewer through the balloon.

I do the film canister rocket experiment. I then just mix a little vinegar and baking soda so they can see gas is being produced. Why is there gas? What gas is it?

I then explain what chemistry is and illustrate with the chemical reaction of baking soda and vinegar,  using full chemical names and chemical formula. Since carbon dioxide is a product we briefly discuss   global warming. I highlight that different compounds in the chemical reaction are gas, solid, or liquid.

I then turn to physics. There are two relevant ideas here:
1. Newton's third law [which they all know word perfect!] and that drives the rocket.
2. When you convert a fixed mass of liquid or solid to gas the total volume increases by a thousandfold. A few grams of carbon dioxide has a volume of several hundred millilitres. Compressing that into the film canister produces a huge pressure.

Now the fun and most important part. We go outside and the students work in pairs where they systematically vary the amount of vinegar they add to the film canister and measure (estimate) the height the rocket goes to. Does more vinegar increase or decrease the height? Why or why not? They record their results. The quicker students I get to repeat their measurements.

After a lot of fun we return to the classroom. I review the chemistry and physics again. Then we compare measurements between different groups, discuss measurement error, and try and draw some conclusions.

The second week I was really happy because a friend came who just finished a Ph.D at Indian Institute of Science. He came from a similar socio-economic background to many of the students. I asked him to tell his life story to the class in the hope it would inspire the students. I don't think a wealthy white Western guy telling poor Indian kids they should study hard and have a lofty goal such as to become a scientist is particularly effective or appropriate.

Follow up. The following week I did the same session with three high school students who were being home schooled by their parents. I was very impressed by their creativity and critical thinking. On their own initiative they realised that it was difficult to make accurate measurements of the height that the rocket went to. Their solution was within about ten minutes to construct the launch device below. Instead of measuring the vertical distance they used a tape measure to measure the horizontal distance the rocket travelled.

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