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April 07, 2014

Music (and girl power)

The work on oscillations led up to the work on Music. I felt a real introduction to musical instruments would be appropriate and it was wonderful to have Magesh from Svaram who works on musicological research come and talk about wind chimes. He demonstrated how different lengths produced different notes and gave (and quizzed) the children on the different aspects (beater, wind catcher). We then moved on to some math on how they calculate the lengths of each of the seven rods. Magesh simplified this to an arithmetic progression (3cm for each pipe) for the width of pipes he brought and described how each rod was hung at 22% of its length. We had a good exercise calculating 22% of each pipe and I have to admit I was impressed how they went about it (and so was Magesh).
For a pipe of length 19 cm
10% -> is 1/10 -> 1.9 cm (move one decimal point)
20% -> 2x10%-> 3.8 cm
2% -> 1/10 of 20% -> 0.38 cm (move one decimal point)
22%-> 4.18 cm
I had shown them this sort of method to convert a fraction into a percentage, but it was exciting to see them apply it to take a % and progressively tend to a more accurate answer from an approximate one.

What was more interesting was the possibility of making a wind chime. In time Magesh was able to provide one set of chimes and three of the girls in the class really wanted to make a chime. The chime requires fairly hard work sawing the metal pipes to the right lengths, polishing with sandpaper to make the finish smooth, drilling holes, logically wiring the setup with a single thread. 

Educationally I found that a lesson on rounding off and approximation came for free when they calculated the numbers and didn't see the point of getting it accurate beyond 1 mm!

The girls spent a class sawing the metal pipes and polishing the end and now the project got socially exciting as I knew that the drilling hole required a power drill (thanks Susan). I took my drill to the class and more or less did what they had expected me to do, set it up and drill the first hole. Magesh has also given a couple of pipes that already had holes (meant for a different instrument). At this point, I talked about safety precautions and handed the drill over to them.

After they realized that their pleads of only 4 more holes left me unmoved their efforts so far forced them to complete the holes for remaining pipes. Pri was the first to step up for the role, then Arc did one only Sub stayed somewhat hesitant.



I had asked Kavitha to ask the girls how they felt the conversation went something like this:
Kavitha: How do you feel?
Pri: When Anna first put the drill in my hand I was shivering.
Kavitha: How do you feel now?
Pri: Its jolly.

From the leftover pieces of the metal pipes they decided to make another mini chime and got down to drilling holes in all of them. Even their teacher got involved and worked with them on the mini chime.


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