Clouds & WeatherSOL 6.3 b,c,d,e

WHAT CAUSES CLOUDS & WEATHER ON EARTH?

• The North & South Pole receive very little of the sun’s radiation because they are farther from the sun, and they receive its light at an angle.

• HEAT!

• The Earth’s surface is heated unequally.

• The Equator receives MOST of the sun’s direct radiation.

• The sun’s radiation heats the air on Earth’s surface.

• That heated air rises, starting a convection current.

• As the warm air rises, cool air falls to take its place.

THE SUN’S HEAT ENERGY MOVES THE AIR!

• The sun also heats the oceans more at the equator causing water to move away from the equator, causing surface currents, like the Gulf Stream.

• The sun’s heat powers the water cycle. It evaporates water all over Earth’s surface!

• This movement of the atmosphere and oceans causes our weather.

THE SUN’S HEAT ENERGY MOVES EARTH’S WATER!

HOW DO CLOUDS FORM?(The water cycle -- of course!)

As bodies of water (oceans, lakes, rivers, etc.) absorb heat energy, the water molecules rise and expand (move apart).

The water BECOMES A GAS (water vapor) We call this EVAPORATION.

The water vapor cools in the upper atmosphere and the water molecules condense (collect together) and form clouds

Clouds are NOT GAS -they are tiny liquid water particles – Think about it…YOU CAN SEE THEM so they can’t be a

gas…THEY ARE A LIQUID!

condensation

evaporation(from bodies of water)

transpiration(water from

plants)

precipitation

CLOUD TYPESTHERE ARE THREE MAIN TYPES OF CLOUDS:

CUMULUS Puffy clouds that look like cotton balls,

often with a flat bottom.

These clouds signal FAIR

WEATHER (blue skies and sunshine!)

CIRRUSVERY THIN &

WISPY—look like FEATHERS or HORSE TAILS.

Very high up & made of ice

crystals. Usually mean FAIR

WEATHER

STRATUS These clouds

COVER the sky like a BLANKET

These clouds often bring LIGHT

DRIZZLY RAIN –NOT

thunderstorms.

YOU CAN ADD PREFIXES TO CLOUD NAMES TO DESCRIBE THEM BETTER

~ ALTO- means the clouds are HIGH IN THE ATMOSPHERE:

-Altocumulus – high cumulus clouds

-Altostratus – high stratus clouds~ NIMBO or NIMBUS -means the clouds contain RAIN:

-Nimbostratus – blanket-like clouds that contain rain

-Cumulonimbus – Cumulus clouds that grow really tall and are often ANVIL shaped.

Cumulonimbus clouds produce SEVERE WEATHER like THUNDER, LIGHTNING, HAIL,

STRONG WINDS & sometimes TORNADOES!