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294

weather

OLogy Series
geology
card
294

weather

OLogy Series
geology

What was it like outside when you left your house today? Cool and windy? Hot and sunny? That's the weather: the conditions of the air, or atmosphere, around you where you are, right now. Weather is always changing. It can be rainy one day and sunny the next. That's why we depend on weather forecasts to tell us what the weather will be like from day to day.

Some things that we measure about the weather are temperature, humidity, and:

average annual rainfall

tide levels

wind speed

Are you right?

Correct!

Precipitation, cloudiness, and air pressure are other weather conditions. Weather describes these conditions for a short period of time, like today, tomorrow, or this week. The average weather condition over several years is called climate.

The movement of _____ cause weather changes from one day to the next:

air masses

clouds

the Sun

Are you right?

Correct!

Air masses are large bodies of air with a common temperature and humidity. As they move, weather changes. If a cold air mass moves in and replaces a warm air mass, it can bring cooler, stormy weather.

Humidity is a measure of the amount of _____ in the air.

water vapor

heat energy

sunlight

Are you right?

Correct!

The air holds invisible water called water vapor. Humidity is related to temperature. The warmer the air, the more water vapor it can hold.

A region's weather from season to season is impossible to predict.

Fact
or
Fiction
?

Fiction

Weather can change day to day, but every region has typical weather patterns. Some places are almost always cold, windy, or dry. These patterns describe the climate.

A sudden change in weather is a sign that the climate is changing.

Fact
or
Fiction
?

Fiction

A single weather event does not say much about climate. To identify climate change, we must look at the weather from the same place over long periods of time (years or decades).

Energy from the Sun causes wind.

Fact
or
Fiction
?

Fact

The Sun warms the air in some places more than others. When warm air rises, cool air moves in to replace it. This moving air is wind! Energy from the Sun drives all our weather.

Definition: the condition of the atmosphere at any
given place and time
Factors: temperature, precipitation, wind speed and direction, air pressure, and humidity
Extreme Weather: tornadoes, hurricanes, droughts, thunderstorms, heat waves, snowstorms
Cool Fact: Clouds can help us predict weather. Thin, wispy clouds can signal fair weather, while big, dark clouds bring thunderstorms.

Image credits: courtesy of AMNH.