Question of the Week

B R Sitaram

Here are the answers to last month’s questions!

Q 1. One of the most common musical instruments that you see in concerts is the harmonium, especially in Hindustani music concerts. In fact, when a student learns vocal music, she is often made to learn the harmonium as well. However, many purists consider the harmonium to be inappropriate for Hindustani classical music. Why is this so?
A. Indian classical music uses a scale of frequencies called the chromatic scale, where the frequency of pa is exactly 3/2 times the frequency of sa and that of ma is exactly 4/3 times the frequency of sa. This means that the second harmonic of pa (in fact all even harmonics of pa) will exactly match the third harmonic (all multiples of three) of sa and will lead to a richer tone. You can hear this very clearly when you are tuning a tanpura. At the right frequency, the sound will suddenly become very rich.

For the last 250 years or so, Western classical music has been using a different scale called the Scientific or Equitempered scale. In this scale, the ratio between any two semitones (sa and re komal, re komal and re, re and ga komal, etc.) is the same and is equal to 21/12. This means that the ratio between sa and pa is no longer 3/2, but 1.498307…. No harmonic of sa will ever match a harmonic of pa, as this number is actually irrational.

The scientific scale has the advantage that any note can be chosen as sa, the scale sounds exactly the same. This is a great advantage in orchestral music, where different instruments have to use the same frequency as their sa (or C). The harmonium is normally tuned to the scientific scale, not the chromatic scale and its sound can interfere with the tanpura.

Q 2. Very often, we see two celestial objects very close to each other in the sky. For example, sometimes Venus and Jupiter will be very close to one another. What are the consequences of this happening? What are the chances of their colliding with each other?
A. Nil. They are extremely far away from each other. Their appearing close to one another is simply a trick of perspective! A similar phenomenon happens with the stars. We imagine that they form groups but in reality they are extremely far away from each other and it is only from the earth (and nearby places) that they make the shapes they do.

Q 3. Why does a peacock dance in the monsoon? Why does a snake move from side to side in front of a snake-charmer?
A. The peacock dances because it is the mating season, not because it loves the rain! It is trying to impress a nearby peahen! The snake has no ears to hear sound through the air, it moves from side to side to keep its head still with respect to the musical instrument, so that it can strike if needed.

Q 4. You are planning to send a message to your spouse/boy friend/girl friend on Valentine’s day. You decide to be biologically correct in the choice of image on your greeting card. What part of the body will your card show to express your love for the recipient?
A. The real centre for human emotions is the amygdala, a small almond shaped part of the brain! In fact, the name amygdala means “almond shaped” and it is a part of the limbic system. So the appropriate part would be the amygdala and an appropriate gift would be an almond!

Questions for this month

  1. When a solar eclipse takes place, only very few places on earth can see it and people travel hundreds of kilometres to see it. However more than half the earth can see a lunar eclipse. How come?
  2. Many photocopying machines, those that can enlarge an image while copying, have a setting for 142%. Why 142? Why not 150 or 200?
  3. Why are many packed food items like wafers sold in 28 g packs? Why not 25? Why not 30?
  4. What time of the day is right for having dinner? Morning, afternoon or night?

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