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Why are some clouds built up of water droplets while others are made up of ice crystals?
Wiki User
∙ 12y ago
For ease of explanation we may say that it all depends on the height of the clouds. Cirrus clouds are high and thin and made entirely of ice crystals forming above 20,000 feet. Low clouds are formed when water vapor turns back into liquid water drops, called condensation. The more the cloud rises the cooler it becomes until ice crystals are formed
Wiki User
∙ 12y ago
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How earth's surface is built up and torn down?
water, air, clouds
Electricity released which has built up in thunder clouds by evening?
The discharge of electricity built up during a storm can be dangerous. It is a static discharge that is generated by positive an negatively charged clouds. When these clouds come in close contact with each other there is an electrical static discharge. This is known as lightning.
Is the rain clean or dirty?
It depends on where you are. Everyone assumes that clouds are sterile, but scientists have recently discovered that clouds contain a species of bacteria called Pseudomonas. These bacteria live in the air and seem to use clouds as a way of transporting themselves. It's able to do this because it has a way of causing ice nucleation - It's got certain chemicals on it's surface that makes tiny ice crystals form, and this makes the cloud form ice crystals around the bacterium. This makes it heavier, and so it flutters down to earth - using the clouds and winds as a transport mechanism. These bacteria don't seem to cause any harm to humans though. What can harm you are the other chemicals that are dissolved in the water as the rain falls down to earth. If you're isolated from pollution sources, the rain is coning from a pristine ocean and will be pretty clean. If you're in a built up area, or downwind of heavy industry, power stations etc, these things can be pumping out all sorts of chemicals - particulates, carcinogens, dioxins and even heavy metals. These particles get into clouds and encourage the clouds to form water droplets, falling as rain. It's also interesting to note that some of the dust that rain deposits on your car has come all the way from the Sahara desert. Dust from the Sahara gets blown high into the atmosphere and is distributed accross the globe.
Which city is above the clouds in China?
The city if Lhasa. It is built near the edge of the Himalayas.
How do you make an igloo in antarctica?
Igloos are built as survival shelters and can be carved from the drifts of frozen ice crystals.
Will it rain during the super bowl?
It depends on the amount of water built up in the clouds above
Why do in summer sky looks WHITE in colour?
Because of clouds or pollution if in a large built up city.
Which monument was built in 2nd half of 18th century?
Among others built in a similar time, the Chowmohalla Palace was built in 1750.
Are most horses built for work or for play?
Most are built for work such as, pulling carts, plowing, racing, etc. But, some others can be built for play.
What is the difference between hurricane and thunderstrom?
a hurricane is like a tornado but on water while a thunderstorm is electricity built up in the clouds waiting to strike
Did the Erie Canal lead others to build canals?
Yes there were other canals built because of the success of the Erie Canal. Canada built one and Ohio built several.
Why did the sweat form drops?
The Formation of Clouds depends largely on the availability ofWater vapour and dust Naturally occurring clouds are composed mostly of water in its liquid or solid state. Firstly we need a sufficient quantity of water vapour to transform into the liquid or solid states. The water vapour content of the atmosphere varies from almost 0% to about 4%, depending on the moisture on the surface beneath and the temperature of the air. Second we need a small amount of fine dust. This is needed for condensation nuclei, upon which water vapour is able to condense or deposit as a liquid or a solid. Certain Particles, such as sea salts and clay, make very good condensation nuclei. When there is sufficient water vapour in the air along with the required dust particles it must be cooled to a temp where droplets or ice can form on the particles. At this point clouds are formed Air moving vertically (up or down) is Very important in the weather processes, especially where clouds and rain are concerned. Ascending air currents take us up into the areas of the atmosphere where Precipitation is more likely to be initiated. Descending currents reverse the process until only water vapour and dust makes up the air mass. Whatever the cause, when air rises it's pressure has to change to match surrounding air, Air pressure goes down as it goes up, which causes it to expands. And as it expands, it cools. The higher it rises the cooler it becomes. As air cools, its relative humidity increases, (Humidification) .the water vapour content in the air has remained the same, however the ability of the air to hold water vapour (The saturation threshold) has decreased at it was cooled. As a result of decreasing the saturation threshold, relative humidity increases. Cooling is the effective method for increasing relative humidity but it is not the only one. Adding water vapour through evaporation or mixing with a more humid air mass is another. To form clouds humidification may eventually bring the air in a given area to saturation. (i.e.) relative humidity reaches 100 percent. Usually a little more humidification is required taking the relative humidity to over 100 percent, this is known as the state of supersaturation needed to form cloud. When air becomes supersaturated, the water vapour in it looks for ways to condense out. If the quantity and composition of the dust content is ideal, condensation may begin at a relative humidity of below 100 percent. If the air is very clean, it may take high levels of supersaturation to produce cloud droplets. But typically condensation begins at relative humidity a few tenths of a percent above saturation. Condensation of water onto nuclei (or deposition of water vapour as ice on freezing nuclei) begins at an altitude known as the cloud base (or lifting condensation level). Water molecules attach dust particles to form cloud droplets which have are about 20 micrometres (0.02 mm) or less in size. The droplet volume is usually a million times greater than the typical condensation nuclei. Clouds are made up of large numbers of cloud droplets, ice crystals, or both. As a result of their small size and relatively high air resistance, they are able to remain suspended in the air for long periods of time, especially if they stay in rising air currents. The average cloud droplet has a terminal fall velocity of 1.3 cm per second in still air. When rain falls, drops of rain are more than one millimetre in size. A raindrop with a diameter 2 mm has the equivalent of a million cloud droplets in of (0.02 mm diameter). Therefore to get rain from a cloud more has to happen within it to that form droplets heavy enough and big enough to fall to the ground. Increased cloud water content is required before we can expect any rain This means the cloud has to continue to rise. Water vapour has a property of releasing heat when changing to liquid and also to solid states, (latent heats of condensation and of deposition), respectively. When this heat is released the surrounding air is warmed, causing the surrounding air to rise. We can see this in the formation of cumulus clouds growing vertically. At this point condensation continues however the coalescence of the cloud droplets causing them to increase in size until they become viable raindrops is a much faster process. This process is further aided by strong updrafts and turbulence forcing droplets to collide and grow more rapidly. The best conditions for droplet growth are when ice crystals are present in a cloud. Under prime conditions a droplet may reach -40 oC (or oF) before it freezes. So there are areas in a cloud were ice crystals and water droplets co-exist. If ice crystals and supercooled droplets are near each other, a movement of water molecules from the droplet to the crystals occurs. As a result the ice crystal gets bigger and the water droplet reduces in size. As crystal grows at temperatures of around -10 oC (14 oF), it begins to develop arms and branches, resulting in the formation of snow. These crystals besides being very efficient at growing at the expense of water droplets also stick to each other forming snowflakes. At last water ice or snow has built up in sufficiently large quantities to be able to fall back to earth.
