Search results
Results from the WOW.Com Content Network
The water droplets in a cloud have a normal radius of about 0.002 mm (0.00008 in). The droplets may collide to form larger droplets, which remain aloft as long as the velocity of the rising air within the cloud is equal to or greater than the terminal velocity of the droplets. [9]
When no CCNs are present, water vapour can be supercooled at about −13 °C (9 °F) for 5–6 hours before droplets spontaneously form. This is the basis of the cloud chamber for detecting subatomic particles. [3] The concept of CCN is used in cloud seeding, which tries to encourage rainfall by seeding the air with condensation nuclei.
The droplet concentration of a cloud is the number of water droplets in a volume of cloud, typically a cubic centimeter (Wallace, 2006). The formula for the droplet concentration is as follows. = / In this equation, N is the total number of water droplets in the volume, and V is the total volume of the cloud being measured.
Clouds form when wet air cools (often because the air rises) and many small water droplets nucleate from the supersaturated air. [1] The amount of water vapour that air can carry decreases with lower temperatures. The excess vapor begins to nucleate and to form small water droplets which form a cloud.
The shape of liquid water drops is generally spherical because of the effects of surface tension. Depending on the size of the drop the friction of the air flowing past a falling drop may squish the bottom on the drop so that it is slightly non-spherical. However, solid ice does not generally form into nice spherical shapes.
This is an accepted version of this page This is the latest accepted revision, reviewed on 2 January 2025. Visible mass of liquid droplets or frozen crystals suspended in the atmosphere For other uses, see Cloud (disambiguation). Cloudscape over Borneo, taken by the International Space Station Part of a series on Weather Temperate and polar seasons Winter Spring Summer Autumn Tropical seasons ...
The most common way to form an ice crystal starts with an ice nucleus in the cloud. Ice crystals can form from heterogeneous deposition, contact, immersion, or freezing after condensation. In heterogeneous deposition, an ice nucleus is simply coated with water. For contact, ice nuclei will collide with water droplets that freeze upon impact.
The nucleation process of water droplets/ice micro-crystals from water vapor reproduced in the CLOUD experiment and also directly observed in the Earth atmosphere do not only involve ions formation due to cosmic rays but also a range of complex chemical reactions with sulfuric acid, ammonia and organic compounds emitted in the air by human ...