Author Question: What is the main difference between a raindrop and a cloud droplet? What will be an ideal ... (Read 116 times)

kfurse · **on:** Jul 13, 2018

What is the main difference between a raindrop and a cloud droplet?
What will be an ideal response?

Question 2

Is silver iodide used as a cloud seeding agent in warm or cold clouds? Why is it the most commonly used cloud seeding agent?
What will be an ideal response?

otokexnaru · **Reply #1 on:** Jul 13, 2018

Answer to Question 1

ANSWER: An ordinary cloud droplet is extremely small, having an average diameter of 20 micrometers or 0.002 cm. A typical cloud droplet is 100 times smaller in diameter than a typical raindrop. If a cloud droplet is in equilibrium with its surroundings, the size of the droplet does not change because the water molecules condensing onto the droplet will be exactly balanced by those evaporating from it. If, however, it is not in equilibrium, the droplet size will either increase or decrease, depending on whether condensation or evaporation predominates.

Answer to Question 2

ANSWER: Cloud seeding has been attempted in both cold and warm clouds.
Silver iodide has a crystalline structure similar to an ice crystal, which is why it acts as an effective ice nucleus at temperatures of -4C (25F) and lower. Silver iodide causes ice crystals to form in two primary ways:
1) Ice crystals form when silver iodide crystals come in contact with supercooled liquid droplets.
2) Ice crystals grow in size as water vapor is deposited onto the silver iodide crystal.

Silver iodide is much easier to handle than dry ice, since it can be supplied to the cloud from burners located either on the ground or on the wing of a small aircraft. Although other substances, such as lead iodide and cupric sulfide, are also effective ice nuclei, silver iodide still remains the most commonly used substance in cloud-seeding projects.