Study 4.6 - Weather

From VDOE's Curriculum Framework (a student friendly version is located on the activity page in the Study Guide for each standard)

Standard 4.6 - Weather

The student will investigate and understand how weather conditions and phenomena occur and can be predicted. Key concepts include
a) weather measurements and meteorological tools (air pressure-barometer, wind speed anemometer, rainfall-rain gauge, and temperature-thermometer); and
b) weather phenomena (fronts, clouds, and storms).

Standards in yellow
Explanation in white

• Temperature is the measure of the amount of heat energy in the atmosphere.

·• Air pressure is due to the weight of the air and is determined by several factors including the temperature of the air.

Cold air is denser and heavier than hot air, and so exerts greater air pressure.

• A front is the boundary between air masses of different temperature and humidity.

All fronts are boundaries between masses of air with different densities, usually caused by temperature differences (cold air is denser than hot air).

A high pressure air mass brings cooler, drier air. A low pressure air mass brings warmer, more humid air.

COLD FRONT
• A cold front is a warm-cold air boundary with the colder air replacing the warmer.

• While a winter cold front can bring frigid air, summer cold fronts, summer cold fronts bring air that might be only a few degrees cooler, but much less humid. Click here or here to read more about cold fronts.

WARM FRONT
• A warm front is the boundary between warm and cool, or cold, air when the warm air is replacing the cold air. It sounds good, but warm fronts often bring days of wet weather.

• As the warm air advances northward it rides over the cold air ahead of it, which is heavier. As the warm air rises the water vapor in it condenses into clouds that can produce rain, snow, sleet or freezing rain. Click here for more on warm fronts.

•    Cirrus, stratus, cumulus, and cumulo-nimbus clouds are associated with certain weather conditions.
•    Extreme atmospheric conditions create various kinds of storms such as thunderstorms, hurricanes, and tornadoes.·
•    Different atmospheric conditions create different types of precipitation.

• Cirrus clouds are feathery and fibrous clouds. They are associated with fair weather. Cirrus clouds often indicate that rain or snow will fall within several hours.			Cirrus Clouds
• Cumulus clouds are fluffy and white with flat bottoms. They usually indicate fair weather.		Cumulus Clouds
Cumulo-nimbus clouds However, when they get larger and darker on the bottom, they produce thunderstorms.		Cumulonimbus Cloud produce thunderstorms and extreme weather
• Stratus clouds are smooth, gray clouds that cover the whole sky (block out direct sunlight). Light rain and drizzle are usually associated with stratus clouds.	Stratus Clouds

• Meteorologists gather data by using a variety of instruments
• Meteorologists use data to predict weather patterns.


barometer measures air pressure.	anemometer measures wind speed.	rain gauge measures precipitation.	thermometer measures the temperature of the air.