NCERT Solutions Exploring Society: India and Beyond Chapter 2 Measuring wind — In-text Questions
Book page 36 Updated on2026-09-05
Q1.
So, how do we measure this direction and speed?
Answer
With two different instruments — one for where the wind comes from, one for how fast it blows.
Instrument
How it works
What it tells us
Wind vane (weather vane)
A rotating arm with a pointer at one end and a tail at the other. The wind pushes the tail, so the pointer swings round and points into the wind. It responds even to a light breeze.
Wind direction
Wind sock
A cloth tube on a mast, used on airport tarmacs and at factories that release ash or gases. It fills and points downwind.
Wind direction at a glance, for pilots taking off and landing
Anemometer
Three or four metal cups on a vertical shaft. The stronger the wind, the faster they spin; a meter at the bottom counts the spins in a fixed time.
Wind speed in km/h
A wind vane turns until its pointer faces the wind; an anemometer's cups spin faster as the wind grows stronger.
Why both readings are needed: Speed alone does not tell a pilot whether it is safe to land, and direction alone does not tell a farmer how quickly the soil will dry. Together they say where the weather is coming from and how forcefully — which is why wind direction helps farmers predict where the rain will arrive from, and why a higher wind speed dries the soil faster.