### fluid | air:

Cold air
* Most cold air creates pressure
  - wind
  - has pressure
  - holds moisture
* Some cold air affects breathe patterns.
* Some cold air causes vapor
  - water vapor
* Some cold air creates humidity
  - saturate humidity
  - snowfall
* becomes thicker and falls, and warm air becomes thinner and goes up.
* brings on headaches, rheumatism, neuralgia of chest, spine and ovaries, vertigo.
* can aggravate respiratory difficulties
  - cause blood pressure to go up, especially when skin is exposed
  - enter the collector through holes, and warm air can escape through outside surfaces
* can hold a lot less moisture than warm air, so the moisure condenses into a visible cloud
  - more water vapor than warm air
  - push hot air up because hot air is less dense
  - seep in where cables and wires enter a house
  - trigger asthma
* contains less moisture than warm air.
* enters rooms.
* falls in cold areas, travels to warm areas, and rises
  - off the inside of a window, just like rain falls off the outside
* flows into swales, and ridgetops provide positive air movement in the summer
  - like water, down hills and through canyons
* formed at the poles is deflected to form polar easterly winds.
* has a very low moisture-holding capacity
  - effects
* has less water vapor than warm air
  - low moisture content
* holds less moisture than temperate air
* is another common cause of defoliation
  - blown over the wax surface so that a solid layer is formed
  - dense so it is able to quickly plow a warm air mass ahead of it
  - dense, heavy air that results in less efficient scent dispersal
* is denser than warm air, and tends to sink
  - denser, tends to barrel into warm air like a bulldozer
  - heavier than hot air and falls, keeping all of the packed food cold and safe
* is heavier than warm air and behaves like water
  - then warm air
  - inhaled and warm air exhaled
  - less capable of holding moisture before it reaches the saturation point
* is located in freezers
  - refrigerators
* is more dense than warm air and a cold front moves faster than a warm front
  - air, i.e., it weighs more
  - warmer air and collects in some of the mountain valleys
  - much denser than warm air and, consequently, is heavier
  - said to have a high pressure
  - trapped near the ground by a layer of warm air
* means extremely low humidity.
* needs to circulate freely in order to keep foods cold.
* presses down on the earth with a greater pressure than warm air.
* takes up less space than warm air.
* tends to hit higher elevations, such as hilltops, and low valleys first.
* weighs more than warm air, so the pressure of cold air is greater.
+ Earth, What it is made of, Air: Geology
  * Rain and storms are both in this level. Both come about because this part of the air gets colder as it goes up. Cold air becomes thicker and falls, and warm air becomes thinner and goes up. The turning Earth moves the air as well and air moves north and south because the middle of the Earth generally gets more power from the Sun and is warmer than the north and south points.
+ Precipitation: Meteorology :: Words
  * Condensations occurs when water molecules slow down as they cool and change into a solid or liquid. Condensation is the opposite of evaporation. When air rises, it cools by an adiabatic process. Air rises when cold air pushes hot air up. Cold air can push hot air up because hot air is less dense. Rain, snow, sleet, dew, frost, hail, and drizzle are all forms of precipitation. If liquid, it can be measured using a rain gauge. The most common form of solid precipitation is snow. Snow is made when temperatures are so cold that water vapor changes directly to solid crystals.

Colder air
* holds less water.
* replaces existing warmer air in a cold front situation.