When water vapor in the air becomes liquid water or ice crystals.

How do clouds form?

Water in the Sky Evaporation and

Condensation: Changing Water

There are three types of water. When it is a solid we call it ice.

When it is a liquid we call it water.

When it is a gas we call it vapor.

These three different typesof water are called states.

Water can change its state. When ice melts, changing into water, or when water evaporates, changing into vapor, a little heat is needed. When water freezes into ice or condenses from vapor to a liquid, a little bit of heat is released. The heat that is needed for or released from these changes in state is called latent heat.

How Clouds Are FormedCooling air that contains water vapor will cause the vapor

molecules in the air to slow down. As they slow down, some

molecules are not able to maintain their vapor form. They

cluster (condense) in the air to form tiny liquid droplets.

Typically they need some sort of particle, such as dust, to

condense upon. These particles are called condensation.

A cloud is composed of tiny water droplets (or ice crystals)

that are suspended in the air. If the droplets become large

enough, they may be visible as a cloud or fog. They may

also fall to Earth in the form of rain (or snow).

CondensationWhen the water vapor reaches the high cool air, it turns into water drops that form the clouds.This is condensation and is part of the water cycle.

TYPES OF CLOUDSThere are many types of clouds.Clouds are classified by:1. Their color

2. Their shape and size 3. Where they form in the

atmosphere.

STRATUSSheets of low, grey clouds that bring light

snow, rain, or drizzle.

FOGA cloud in contact with the ground. Fog is a

type of Stratus cloud.

CUMULUSWhite and puffy clouds that usually

mean good weather.

CUMULUSCumulus clouds are fun to watch.People often see “pictures” in the sky made by Cumulus clouds.

CIRRUSThin, featherlike clouds that are made of ice

crystals high in the atmosphere. Usually means a change in the weather is coming.

CIRRUS CLOUDS

What does the color of a cloud tell you?

The color of a cloud lets you know how much water it contains.White clouds have little water.Dark clouds usually mean heavy rain.Grey clouds can mean snow or rain.

Where do clouds form?

Clouds form along weather fronts.

Let’s See If You CanName.That.

Cloud!http://www.bbc.co.uk/schools/whatisweather/aboutweather/cloud.shtml