What is Weather?Lesson 3

Vocabulary

Atmosphere: The air around Earth

Oxygen: A gas that all living things need, and that plants give off into the air

Weather: What is happening in the atmosphere at a certain place and time

Temperature: The measure of how hot or cold something is

Anemometer: A weather instrument that measures wind 

The air around Earth is the atmosphere. The atmosphere is important because it has oxygen and also has gases that plants need to live.

Water vapor is in the atmosphere. Clouds form from water vapor. Rain, snow, and other kinds of precipitation fall from clouds.

Types of Clouds

1. Cirrus Clouds: are the highest clouds. They look like wisps of hair. Do not produce precipitation that reaches Earth.

2. Cumulus Clouds: are lower than cirrus clouds, they look puffy. They can bring strong storms with rain and hail.

3. Stratus Clouds: are the lowest clouds. They look like a sheet or a layer of clouds. Usually brings rain, sleet, or snow.

• The weather in a place depends on where the place is.

Weather instruments help gather weather data.

• Thermometer: used to find thetemperature. Hot or cold a place is.

• Anemometer: measures windspeed.

Dangerous weather changes are sometimes called severe weather. They bring heavy rain, snow, lightning, high winds, and big temperature changes may also happen.

The kind of weather depends on the temperature, the speed and direction of wind, and the precipitation.

People use weather instruments to predict weather. One instrument that is used to predict weather is a weather satellite. A weather satellite in space may take pictures of clouds then sends the pictures to Earth and people use the pictures to see how clouds move.

• bring heavy rain and high winds. • Hail and lightning happen.• occur during hot weather• sometimes have strong winds

• is a spinning column of air that touches the ground.

• happen in some strong thunderstorms.

• They are very dangerous.• Precipitation: rain and hail are

possible• Temperature: generally warm• Wind: very strong

Floods • happen when a lot of rain falls in a short amount

of time.• Rivers and ditches can overflow and cause

problems. • Temperature: usually warm or mild• Wind: wind speed may change during flooding

Drought • is a time with very dry weather.• the dryness lasts for a long time. • Rivers and lakes can begin to dry up.

Temperature: may change during drought• Wind: windspeed may change during

droughts

Blizzards• happen in the winter when it is cold and

below freezing. • They bring heavy snow and strong, cold winds.• Precipitation: snow—mostly heavy

Temperature: below 0°C (32°F)• Wind: at least 56 kilometers per hour (35

miles per hour)

Hurricanes • are the largest storms on Earth.• They form over oceans when the water is warm. • can cause tornadoes and thunderstorms to form.• Precipitation: rain - mostly heavy• Temperature: generally warm• Wind: at least 119 kilometers an hour

(74 miles an hour)

Heat Wave• When the temperature is very hot for a long time, a

heat wave may be happening. • Heat waves last from a few days to several weeks.

They can be very dangerous.• Precipitation: rain is possible• Temperature: generally from 35°C (95°F) to 44°C

(110°F) and above

• Wind: wind speed may vary during a heat wave

Ice storms• happen in the winter when rain freezes on things. • The ice can be heavy enough to break power lines

and damage trees. The slippery ice can make walking or driving difficult.

• Precipitation: precipitation falls as rain, but freezes when it lands

• Temperature: around 0°C (32°F)• Wind: wind speed may change during

the storm