Question

Particles that are not used for cloud seeding in artificial rain making is:

• A. Silver iodide
• B. Dry ice
• C. Common salt
• D. Kaolinite

Hint:

Think about which of these four substances is just a clay mineral with no ice forming or water attracting role.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks which of the four listed substances is not actually used as a cloud seeding agent for making artificial rain.

Step 2: Key Formula or Approach:
Cloud seeding works by adding particles into clouds that either provide ice nuclei for cold cloud seeding or act as hygroscopic, water attracting particles for warm cloud seeding, encouraging droplets to grow big enough to fall as rain.

Step 3: Detailed Explanation:
Silver iodide has a crystal structure close to that of natural ice, so it works as an effective ice nucleating agent in cold clouds, this is the most widely used cloud seeding chemical in the world.
Dry ice, which is solid carbon dioxide, cools the surrounding air sharply when it sublimates, this rapid cooling causes water vapor to freeze into tiny ice crystals, so dry ice is also a standard cold cloud seeding agent.
Common salt, sodium chloride, is hygroscopic, meaning it pulls in water vapor around itself, when sprayed into warm clouds it helps water droplets combine and grow large enough to fall as rain, so it is used in warm cloud seeding.
Kaolinite is a clay mineral used mainly in ceramics, paper and as a filler material, it is not a standard cloud seeding agent, it lacks the specific ice nucleating or strong hygroscopic property that silver iodide, dry ice and salt provide.

Step 4: Final Answer:
Since silver iodide, dry ice and common salt are all genuine cloud seeding agents while kaolinite is not, option 4 is correct.