Q1.
We know they are located at a higher altitude than the plains below, but how does that explain their cooler temperature?
Answer
The chapter gives two simple reasons why temperature decreases as altitude increases.
- The air gets thinner. Atmospheric pressure — and therefore air density — decreases as altitude increases (as we saw in the chapter ‘Understanding the Weather’). As the air gets less dense, it gets cooler.
- You are farther from the heated surface. The Sun heats the surface of the Earth, and the air is warmed from below. So the farther away from the surface you are, the less hot the air will be.
That is why the Himalayas are so high that many peaks stay below water's freezing point all year and remain covered in snow — and why hill stations are popular tourist centres.
| Hill station | State / region |
|---|---|
| Munnar, Theni, Udhagamandalam (Ooty) | Kerala and Tamil Nadu — the Western Ghats and Nilgiris |
| Madikeri, Mahabaleshwar | Karnataka and Maharashtra — the Western Ghats |
| Mount Abu | Rajasthan — the Aravalli Range |
| Shimla, Nainital, Darjeeling | Himachal Pradesh, Uttarakhand, West Bengal — the Himalayas |
| Tawang, Shillong | Arunachal Pradesh and Meghalaya — the North-East |
Tip: people climbing a mountain often expect it to get warmer because they are moving closer to the Sun. The distance saved is a few kilometres out of about 150 million — nothing at all. What matters is the thin air and the distance from the warm ground below.