Weather

Part 2

The Water Cycle

How does this water vapor get into the air?

• Water EVAPORATES from oceans, lakes, rivers, or puddles!

• Think back to our activity with the dish and the water drops!

Making our own CLOUD!

• After water is evaporated, it will CONDENSE and a cloud will form!

• We know that some days, we have more clouds in the atmosphere than other days!

• We’re going to make our own cloud to see the conditions that clouds form!

• A cloud is a mass of billions of very small water droplets!

• In our cloud model, we’re going to have a jar, hot water, plastic wrap, and ice cubes! Let’s brainstorm some ideas for how this

will work…

What exactly is a CLOUD?

What happens in the jar?

• The air in the jar gets cloudy and the water is evaporating or changing to water vapor!

• The water vapor we see is a miniature cloud!

• What happens to the water vapor in the jar?

• Answer: It rises!

• As the water vapor gets

further from the hot water, it

begins to cool. Water droplets begin to form.

After evaporation and condensation, we get …

SleetRain

Hail

Snow

Families of Clouds

• Clouds occur in many different shapes and sizes and each help us to predict the weather!

• There are three main type of cloud families. Can you name them?

1) Cumulus

2) Stratus

3) Cirrus

Cumulus Clouds

• Puffy clouds• Form when large areas of warm, moist air rise

upward from Earth’s surface

What’s the weather usually

like when we see Cumulus clouds in the

sky?

Stratus Clouds

• Flat and gray • Seem to cover the sky

• Form when a flat layer of moist air rises very slowly

Stratus clouds that are close to the ground are what we call

FOG!

These clouds usually mean rain may be coming!!

Cirrus Clouds

•Look like commas

•Very WHISPY!

•Form when the air rises high enough

for ice crystals to form!

How Clouds are named and grouped

• Scientists use the word NIMBUS to describe a RAIN CLOUD.

• Nimbus is the Latin word that means “rain”• Clouds are also grouped by height.

• High in the sky = cirro-• Medium height in the sky = alto-

Types of clouds

Weather Maps

Weather Maps can look many

different ways!

Weather maps are maps that show weather

conditions over a large area and help meteorologists and weather forecasters

predict the weather!

• We looked at the Weather Map Symbols on page E58 in our book!

What’s the symbol for…

A cold front?

A warm front?

Weather Map Symbols

What is an air mass?

• An air mass is a body of air with the same general temperature and air pressure

throughout!

• The air masses are constantly moving!

• The boundary between air masses with different temperatures is called a FRONT.

Cold Fronts

• A COLD front is when a cold air mass moves into a warm air mass. This often produces

thunderstorms!

Warm Fronts

• A warm front is when a warm air mass moves into a cold air mass. This often brings fair

weather or a light rain

TIME TO

REVIEW!

Investigation 1 Questions

1. What are the three families of clouds?

Answer: Cirrus, Cumulus, and Stratus!

2. How does a cloud form?

Answer: As water vapor in the air cools, it condenses and can form a cloud!

Investigation 1 Continued…

3. You are going to a picnic when you notice that the sky is filled with a layer of gray clouds. Should you go to the picnic or

should you stay inside? Explain.

Answer: You may want to stay inside because the cloud you see are STRATUS clouds and mean that precipitation may be

coming!

Investigation 1 continued…

4. How can clouds seen from the ground help people predict the weather? What kinds of information do weather satellites provide?

Answer: Different types of clouds are associated with different WEATHER patterns! We can look up in the sky and often tell what the weather will be like because of the clouds! Weather satellites are used to take pictures of clouds, measure the

moisture in the atmosphere, and provide information about the wind and temperature!

Investigation 2

1. What kind of weather often occurs at a cold front?

Answer: Precipitation and thunderstorms are often produced at a cold front

2. What are four types of information that appear on weather maps?

Answer: High pressure, low pressure, temperature, cold and warm fronts, cloud

coverage, etc…

Investigation 2 continued…

3. Suppose you are a weather forecaster for your town. What data would you gather to

make a prediction about the next day’s weather?

Answer: Think about what we’ve been measuring everyday in class! We want to

know the humidity, temperature, air pressure, cloud type, wind direction, wind

speed, and precipitation amount!

Investigation 2 continued…

4. Can weather forecasters always be right in their predictions?

Answer: No, weather forecasters can’t always be correct because sometimes

weather conditions change so quickly that the information they have isn’t correct. Sometimes, weather doesn’t follow the

“normal” patterns!