How to do this task. Table 3.1 in your book prints only four of the categories — Calm, Light breeze, Strong breeze and Storm — and if you look at the speed column you can see the gaps for yourself.
Missing bands: 2–5, 12–38, 50–102 and everything above 117
So there are several categories still to be found, mostly in the middle of the range.
Where to look: the full scale Table 3.1 is drawn from is the Beaufort wind scale, which the India Meteorological Department also uses. Good sources are the IMD website (mausam.imd.gov.in), a school atlas, the encyclopedia section of your library, or the daily weather bulletin in the newspaper, which often names the wind category for the day.
What a good answer must contain — for every category you find, give three things, exactly as Table 3.1 does: (i) the name, (ii) the speed range in km/hr, and (iii) the common effects you could actually observe. Effects are what make the scale usable without any instrument.
Sample answer:
| Wind | Speed (km/hr) | Common effects you can observe |
|---|---|---|
| Light air | 2 – 5 | Smoke drifts sideways instead of rising straight up; a wind vane does not move yet |
| Gentle breeze | 12 – 19 | Leaves and small twigs move constantly; a light flag is lifted; kites fly well |
| Moderate breeze | 20 – 28 | Dust and loose paper are raised; small branches move |
| Fresh breeze | 29 – 38 | Small trees in leaf begin to sway; small waves form on a pond or tank |
| Near gale | 50 – 61 | Whole trees in motion; walking against the wind becomes inconvenient |
| Gale | 62 – 74 | Twigs break off trees; walking is difficult; progress on a cycle is very hard |
| Strong gale | 75 – 88 | Slight structural damage — roof tiles and tin sheets are blown off |
| Violent storm | 118 – 133 | Very rarely experienced; accompanied by widespread damage |
| Hurricane / cyclone force | above 118 (117+) | Devastation — the strength of a severe cyclone crossing the Indian coast |