12. Effects of Water Vapour in the Atmosphere

Question 1

Term

Answer 1

Definition

Question 2

Absolute Humidity

Answer 2

The mass of water vapor present in a given volume of air.

Question 3

Dew Point

Answer 3

The temperature at which air becomes saturated with moisture and condensation begins.

Question 4

Evaporation

Answer 4

The process of turning liquid water into vapor, adding moisture to the air.

Question 5

Sublimation

Answer 5

The transition of water directly from a solid (ice) state to vapor, bypassing the liquid phase.

Question 6

Condensation

Answer 6

The process where water vapor becomes liquid; it is crucial in cloud formation and precipitation.

Question 7

Saturation

Answer 7

A condition where air contains the maximum amount of water vapor it can hold at a given temperature and pressure.

Question 8

Vapor Pressure

Answer 8

The pressure exerted by water vapor present in the air.

Question 9

Relative Humidity

Answer 9

The amount of moisture in the air compared to what the air can hold at that temperature, expressed as a percentage.

Question 10

Hygrometer

Answer 10

An instrument used to measure the moisture content or the humidity of the air.

Question 11

Fog

Answer 11

A thick cloud of tiny water droplets suspended in the atmosphere at or near the Earth’s surface that impedes visibility.

Question 12

Mist

Answer 12

Finer than fog, consisting of tiny water droplets suspended in the air, typically reducing visibility less severely than fog.

Question 13

Clouds

Answer 13

A visible mass of condensed water vapor floating in the atmosphere, typically high above the ground.

Question 14

Precipitation

Answer 14

Any form of water - liquid or solid - that falls from clouds and reaches the ground.

Question 15

Rain

Answer 15

Liquid water in the form of droplets that have condensed from atmospheric water vapor and then become heavy enough to fall under gravity.

Question 16

Snow

Answer 16

Atmospheric water vapor frozen into ice crystals and falling in light white flakes or lying on the ground as a white layer.

Question 17

Sleet

Answer 17

A form of precipitation consisting of ice pellets, often mixed with rain or snow.

Question 18

Hail

Answer 18

Pellets of frozen rain which fall in showers from cumulonimbus clouds.

Question 19

Transpiration

Answer 19

The process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere.

Question 20

Water Cycle

Answer 20

The continuous process by which water is circulated throughout the Earth and its atmosphere.

Question 21

Evapotranspiration

Answer 21

The sum of evaporation and plant transpiration from the Earth’s land and ocean surface to the atmosphere.

Question 22

Humidity

Answer 22

The concentration of water vapor present in the air.

Question 23

Wet-Bulb Temperature

Answer 23

The lowest temperature that can be reached by evaporating water into the air at constant pressure.

Question 24

Psychrometer

Answer 24

An instrument used to measure the relative humidity and dew point in the atmosphere.

Question 25

Cloud Condensation Nuclei (CCN)

Answer 25

Particles on which water vapor condenses to form cloud droplets.

Question 26

Supersaturation

Answer 26

When the air is saturated with water vapor beyond the usual 100% relative humidity, often occurring in cloud formation.

Question 27

Lifting Condensation Level (LCL)

Answer 27

The height at which the relative humidity of an air parcel will reach 100% when it is cooled by dry adiabatic lifting.

Question 28

Virga

Answer 28

Precipitation that evaporates before it hits the ground, often seen as streaks or shafts extending from a cloud.

Question 29

Ice Nuclei

Answer 29

Particles that act as nuclei for the formation of ice crystals in the atmosphere.

Question 30

Stratus Clouds

Answer 30

Clouds that form in flat layers and often cover much of the sky.

Question 31

Cumulus Clouds

Answer 31

Fluffy, white clouds, often with flat bases, that look like rounded piles of cotton.