Chapter 6

Question 1

Hydrologic cycle

Answer 1

The water is on continuous exchange among oceans, the atmosphere and the continents. This unending circulation of earth’s water supply has come to be called the Hydrologic cycle.

Question 2

The hydrologic cycle is a gigantic system powered by energy from

Answer 2

the sun in which the atmosphere provides the vital link between ocean and continents.

Question 3

As water evaporates from ocean, wind transports

Answer 3

moisture-laden air, often over great distances.

Question 4

Complex processes of cloud formation result in

Answer 4

precipitation.

Question 5

Evaporation process is

Answer 5

the evaporating of water vapor from the ocean (water surfaces).

Question 6

Transpiration

Answer 6

a process of evaporating from soil, lakes and grass.

Question 7

evapotranspiration

Answer 7

combination of transpiration and respiration

Question 8

Water in the atmosphere is only

Answer 8

0.001% of the total air

Question 9

The process of changing states requires

Answer 9

heat that can be absorbed or released

Question 10

The process of changing states requires heat that can be absorbed or released. This heat is called

Answer 10

latent heat

Question 11

The heat energy is often measured in

Answer 11

calories.

Question 12

One calorie is the amount of heat required to

Answer 12

raise the temperature of one gram of water 1^oC.

Question 13

Heat is added to the sample in processes of

Answer 13

melting and evaporation

Question 14

Heat is released from the sample in processes of

Answer 14

freezing and condensations

Question 15

Vapor pressure

Answer 15

The water vapor has its pressure that added to the atmospheric pressure.
This pressure of the water vapor alone is called Vapor pressure

Question 16

Saturation vapor pressure

Answer 16

When air is saturated the pressure exerted by the water vapor

Question 17

The saturation vapor pressure rises with

Answer 17

increasing temperature

Question 18

from solid to gas (calories)

Answer 18

580 cal

Question 19

from solid to liquid (calories)

Answer 19

80 calories

Question 20

Absolute humidity is

Answer 20

the mass of water vapor (in kg) in a given volume of air (in m³)

Question 21

It is difficult to monitor the water vapor content of a

Answer 21

moving mass of air

Question 22

Also the air volume is affected by

Answer 22

the changing temperature and pressure, so the use of this method is not a good indicator of humidity

Question 23

Mixing ratio is

Answer 23

the mass of water vapor (in grams) in a unit mass of dry air (in kg)

Question 24

The mixing ratio is not affected by

Answer 24

changes in pressure and temperature as absolute humidity

Question 25

Relative humidity is

Answer 25

a ratio of the air’s actual water vapor content compared with amount of water vapor required for saturation at that temperature

Question 26

The relative humidity changes by:

Answer 26

• adding or subtracting moisture,
• changing temperature.

Question 27

Adding or subtracting moisture: when water vapor is added to a parcel
of air its relative humidity

Answer 27

increases until reaches saturation (the relative
humidity is 100%)

Question 28

Adding or subtracting moisture: when water vapor is added to a parcel of air its relative humidity increases until reaches saturation (the relative humidity is 100%). When the relative humidity exceeds 100% the excess of water vapor

Answer 28

condenses to form liquid water

Question 29

Changing temperature: when the water vapor content remains constant adecrease in temperature results in

Answer 29

an increase in relative humidity

Question 30

Dew point is

Answer 30

the temperature to which a parcel of air would need to be cooled to reach saturation

Question 31

Measuring humidity:

Answer 31

• Hygrometers

Hair hygrometer

The electric hygrometer:

Question 32

Hygrometers:

A variety of instruments called hygrometers can be used to measure

Answer 32

relative humidity

Question 33

variety of instruments called hygrometers can be used to measure
relative humidity. One of the simplest hygrometers is

Answer 33

the psychrometer,

Question 34

A variety of instruments called hygrometers can be used to measure
relative humidity. One of the simplest hygrometers is the psychrometer,
which consists of

Answer 34

two identical thermometer mounted side by side. One thermometer is called the wet bulb, h as a thin muslin wick tied around the end

Question 35

To use the psychrometer the cloth wick is

Answer 35

saturated with water and a
continuous current of air is passed over the wick, either by fanning air past
it. As a result water evaporates from the wick absorbing heat energy from
the thermometer to do so and the temperature of the wet bulb drops.

Question 36

To use the psychrometer the cloth wick is saturated with water and a
continuous current of air is passed over the wick, either by fanning air past
it. As a result water evaporates from the wick absorbing heat energy from
the thermometer to do so and the temperature of the wet bulb drops. The
amount of cooling that takes place is directly proportional to

Answer 36

the dryness of the air

Question 37

To use the psychrometer the cloth wick is saturated with water and a
continuous current of air is passed over the wick, either by fanning air past
it. As a result water evaporates from the wick absorbing heat energy from
the thermometer to do so and the temperature of the wet bulb drops. The
amount of cooling that takes place is directly proportional to the dryness of
the air. The drier the air, the

Answer 37

greater the cooling

Question 38

The larger the differences
between the wet bulb and dry bulb temperatures the

Answer 38

lower the relative
humidity.

Question 39

………………. the two thermometers will have identical readings

Answer 39

If the air is saturated, no evaporation will occur

Question 40

Hair hygrometer

The principle of it is that

Answer 40

the hair changes length in proportion to changes in relative humidity

Question 41

The hair hygrometer uses

Answer 41

bundle of hairs linked mechanically to an indicator that is calibrated between 0 and 100%. The hair hygrometer is less accurate than the psychrometer

Question 42

The electric hygrometer

Answer 42

It contains an electrical conductor coated with a moisture -absorbing chemical. It works on the principle that electric current flow varies as the relative humidity varies.