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Cloud seeding: how artificial rain is induced
খবরে কেন?
Artificial rain cannot come from a clear sky: why silver iodide works, the cloud seeding concept for Prelims
Cloud seeding releases particles such as silver iodide into moisture-laden clouds to stimulate rain; it cannot create rain from clear skies.
Why it matters: asked in UPSC 2025; factual, Prelims-type
What you need to know
2 মিনিট
Cloud seeding is a weather-modification technique in which particles are released into suitable clouds to encourage precipitation.
Silver iodide is the best-known seeding agent because its crystal structure resembles that of ice, so it can act as nuclei on which ice crystals grow; other materials such as dry ice and salt are also used.
It works only where clouds with enough moisture are already present.
সূত্র: Topper IAS editorial (PIB / The Hindu / Indian Express)
মূল তথ্য
Remember these
- Cloud seeding is a weather-modification technique that releases particles into suitable clouds to encourage precipitation.
- Silver iodide is the best-known seeding agent because its crystal structure resembles that of ice.
- Silver iodide acts as nuclei on which ice crystals grow.
- Dry ice and salt are other materials used for seeding.
- It works only where clouds with enough moisture are already present; it cannot create rain from clear skies.
প্রিলিমস · মেইনস
How the exam will ask it
প্রিলিমস
- Cloud seeding is a weather-modification technique that can stimulate precipitation in suitable moisture-laden clouds.
- Silver iodide is used as a seeding agent because its ice-like crystal structure lets it act as ice-forming nuclei.
- Cloud seeding can create rain even in the absence of clouds. (Incorrect: it needs clouds with enough moisture.)
- Besides silver iodide, materials such as dry ice and salt are also used for seeding.
মেইনস
GS-I/III (Geography; Science and Technology): Weather modification is pitched as a response to drought and water stress, but it depends on suitable moisture-laden clouds and so cannot substitute for water management. Its use raises questions of scientific evidence of effectiveness, environmental safety of the agents used and regulation. The way forward is pilot trials with transparent monitoring and independent evaluation, alongside conservation and better forecasting.
PYQ connection
A question UPSC has already asked on this
Artificial way of causing rainfall to reduce air pollution makes use of
- silver iodide and potassium iodide
- silver nitrate and potassium iodide
- silver iodide and potassium nitrate
- silver nitrate and potassium chloride
উত্তর দেখুন
উত্তর: A
Why this matters: today's issue is directly connected to a concept UPSC has already tested. Read the story with this question in mind.
Practise this PYQ →Quick recall
Answer before you reveal
In cloud seeding, silver iodide is widely used because its crystals can act as:
- Ice-forming nuclei
- Hygroscopic condensation nuclei
- Ozone-depleting agents
- Infrared absorbers that dissipate clouds
উত্তর দেখুন
উত্তর: A — The correct answer is ice-forming nuclei, because the crystal structure of silver iodide resembles that of ice.
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