1. The Surprising Composition of CloudsWe think of clouds as being
liquid water and/or ice, but by far the greatest amount of the mass
contained in a cloud is air. Although clouds contain a very large number
of suspended droplets or particles—typically about 1000 per cubic
centimeter—even the largest of these droplets are extremely small.
Therefore, despite their large numbers they amount to relatively little
mass. This might not be too surprising if you recall that water vapor
only accounts for a small percentage of the mass of the atmosphere.
Because the water vapor is so limited, it stands to reason that only a
small amount of ice or liquid water can be deposited or condensed.We can
apply some simple arithmetic to determine the relative mass of air and
liquid water in a cloud. The average cloud droplet has a radius of about
0.001 cm, and the volume of a sphere is equal to...where r is the
radius. Substituting 0.001 cm for r, we find that the average droplet
has a volume of about 4 × 10−9 cubic centimeters.Because the density of
water is about 1 g/cm3, it follows that the mass of each droplet is
about 4 × 10−9 g. Multiplying this value by the 1000 droplets per cubic
centimeter normally found in a cloud gives us a liquid water content of
0.000004 g/cm3.Now we can compare the 0.000004 g/cm3 of water to the
mass of the air. At an altitude of 5.5 km above sea level, for example,
the density of the air is about half that at sea level, or roughly
0.0006 g/cm3. Compare this to the mass of the liquid, and you will find
about 150 times more air than water in the cloud.You can think of this
another way: If a - cloud has a horizontal area of 1 square kilometer
and a height of 1 km, it contains about 4 million kilograms of water.
This is far less than the approximately 600 million kilograms of air in
the same cloud.Why don’t clouds contain much condensed liquid water?
What factor is responsible for the limited amount of water that can
exist in clouds? Get solution
2. The Surprising Composition of CloudsWe think of clouds as being liquid water and/or ice, but by far the greatest amount of the mass contained in a cloud is air. Although clouds contain a very large number of suspended droplets or particles—typically about 1000 per cubic centimeter—even the largest of these droplets are extremely small. Therefore, despite their large numbers they amount to relatively little mass. This might not be too surprising if you recall that water vapor only accounts for a small percentage of the mass of the atmosphere. Because the water vapor is so limited, it stands to reason that only a small amount of ice or liquid water can be deposited or condensed.We can apply some simple arithmetic to determine the relative mass of air and liquid water in a cloud. The average cloud droplet has a radius of about 0.001 cm, and the volume of a sphere is equal to...where r is the radius. Substituting 0.001 cm for r, we find that the average droplet has a volume of about 4 × 10−9 cubic centimeters.Because the density of water is about 1 g/cm3, it follows that the mass of each droplet is about 4 × 10−9 g. Multiplying this value by the 1000 droplets per cubic centimeter normally found in a cloud gives us a liquid water content of 0.000004 g/cm3.Now we can compare the 0.000004 g/cm3 of water to the mass of the air. At an altitude of 5.5 km above sea level, for example, the density of the air is about half that at sea level, or roughly 0.0006 g/cm3. Compare this to the mass of the liquid, and you will find about 150 times more air than water in the cloud.You can think of this another way: If a - cloud has a horizontal area of 1 square kilometer and a height of 1 km, it contains about 4 million kilograms of water. This is far less than the approximately 600 million kilograms of air in the same cloud.Overall, how does the amount of water in a cloud compare to the amount of air in it? Get solution
2. The Surprising Composition of CloudsWe think of clouds as being liquid water and/or ice, but by far the greatest amount of the mass contained in a cloud is air. Although clouds contain a very large number of suspended droplets or particles—typically about 1000 per cubic centimeter—even the largest of these droplets are extremely small. Therefore, despite their large numbers they amount to relatively little mass. This might not be too surprising if you recall that water vapor only accounts for a small percentage of the mass of the atmosphere. Because the water vapor is so limited, it stands to reason that only a small amount of ice or liquid water can be deposited or condensed.We can apply some simple arithmetic to determine the relative mass of air and liquid water in a cloud. The average cloud droplet has a radius of about 0.001 cm, and the volume of a sphere is equal to...where r is the radius. Substituting 0.001 cm for r, we find that the average droplet has a volume of about 4 × 10−9 cubic centimeters.Because the density of water is about 1 g/cm3, it follows that the mass of each droplet is about 4 × 10−9 g. Multiplying this value by the 1000 droplets per cubic centimeter normally found in a cloud gives us a liquid water content of 0.000004 g/cm3.Now we can compare the 0.000004 g/cm3 of water to the mass of the air. At an altitude of 5.5 km above sea level, for example, the density of the air is about half that at sea level, or roughly 0.0006 g/cm3. Compare this to the mass of the liquid, and you will find about 150 times more air than water in the cloud.You can think of this another way: If a - cloud has a horizontal area of 1 square kilometer and a height of 1 km, it contains about 4 million kilograms of water. This is far less than the approximately 600 million kilograms of air in the same cloud.Overall, how does the amount of water in a cloud compare to the amount of air in it? Get solution
