18-1 Flashcards
what is water vapor?
source of all condensation and precipitation, makes up only small fraction of gases in the atmosphere (0 to 4%, critical in weather conditions)
what is water? How does water change its state and what does that allow?
only substance that exists in Earth’s atmosphere as solid, liquid, gas; at temperatures and pressure on Earth water can change its state which allows water to circulate through oceans, atmosphere, solids, and biosphere in water cycle
How is solid made liquid?
energy in the form of heat is applied to solid to make it liquid
what is latent heat? How is it measured and released? where is it stored?
heat to cause melting, not increase temperature; measured in joules or calories, only measured when it returns to solid; stored in liquid water, released as thunderstorms, tornadoes, and hurricanes are created
how is liquid made gas?
evaporation. During evaporation, the higher temperature, fast moving molecules escape surface so average molecular motion of remaining molecules is reduced
what is latent heat of evaporation?
energy needed to convert liquid water into vapor; heat needed to give water molecules motion needed to escape surface of the water and becomes a gas
what is condensation?
process where water vapor changes into liquid by dew, fog, or clouds
what is latent heat of condensation?
water vapor molecules release their stored heat which is important in producing violent weather. transfers heat from tropical oceans towards poles
how is solid made gas?
by sublimation. it is conversed without becoming liquid
what is deposition?
reverse process of sublimation, gas turning into solid directly (water vapor turning into frost)
what is wind-chill effect? how does hair affect it?
Hairs on skin hold a layer of stagnant air over your skin, this acts as a layer of insolation.
Wind blowing over your skin removes stagnant insulating air from body so skin is now exposed to cooler air making you feel colder
what is wind-chill factor?
Increased cooling by wind; stronger the wind the colder you feel
what is saturation?
air molecules in the atmosphere have spaces between them, so water vapor molecules can be held up by air molecules. When the number of water vapor molecules returning to the surface is the same amount going into air
on a hot day is there a lot of humidity or a little?
a lot of humidity; amount of water vapor (humidity) varies day to day
amount of water vapor that air can hold depends on..?
temperature. at colder temperatures air and water vapor move very slowly which makes it easier to join water molecules together (condense) and form rain
with warmer temperatures air and water vapor molecules are..? why can’t condensation occur easily?
moving quickly. Water vapor molecules cannot join together easily so condensation cannot occur easily, air can hold more water vapor than cooler air
what is relative humidity?
measure of amount of water vapor in air, compared to total amount of water vapor it can hold at a particular temperature; the water vapor amount compared to saturation level
if relative humidity is 50%, then how much is the air holding?
only holding 50% of what it is capable of holding
what is dew point?
temperature at which air is saturated and condensation takes place; cold air holds less water vapor than warm air, so as air cools the amount of water vapor it can hold decreases, if it cannot hold it all it condenses into water or ice
what is a psychrometer?
used to measure relative humidity, uses wet and dry thermometers; Wet one has evaporation so it is cooler (water to water vapor takes heat from thermometer)
When the atmosphere is dry what happens to evaporation and temperature?
more evaporation so cooler temperature
the greater the difference in dry and wet bulbs, what happens to the relative humidity?
the lower the relative humidity, dry air causes wet bulb to evaporate more so it cools more
