Vocabulary

**Vocabulary **

 * || __ **air pressure** __

 **Definition:**The weight per unit of area of a column of air that reaches to the top of the atmosphere.

 **Context:**Areas of high **air pressure**, or high-pressure systems, usually have clear skies, and areas of low air pressure, or low-pressure systems, usually have clouds.

__ **atmosphere** __

 **Definition:**The layer of air that surrounds Earth and is made up of nitrogen (about 78 percent), oxygen (about 21 percent), and miscellaneous gases (about 1 percent).

 **Context:**Our weather takes place in the lower part of the **atmosphere**.

__ **front** __

 **Definition:**A narrow zone of transition between air masses that differ in temperature or humidity.

 **Context:**Most changes in the weather occur along **fronts**.

__ **humidity** __

 **Definition:**A measure of the amount of moisture in the air in the form of invisible water vapor.

 **Context:** **Humidity**is important for making weather forecasts, because it can help scientists predict precipitation.

__ **meteorologist** __

 **Definition:**A scientist who studies the weather.

 **Context:** **Meteorologists** use different types of maps to report the weather.

__<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **precipitation** __

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Definition:**Moisture that falls from clouds in the form of rain, snow, sleet, or hail.

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Context:**Without rain or other forms of precipitation, the ground becomes dry, and crops cannot grow.

__<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **temperature** __

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Definition:**The measure of the heat energy of the gases in the air.

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Context:**Changes in temperature lead to changes in air pressure, bringing different kinds of weather.

__<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **weather** __

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Definition:**The state of the atmosphere at a given time in a particular place.

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Context:**The three main factors of **weather** are humidity, air pressure, and temperature.

__<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **wind** __

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Definition:**The movement of air, which tends to move from a high-pressure area to a low-pressure area.

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> **Context:** **Winds** are named for the direction from which they blow, so an easterly wind blows from the east. ||