First Grade Weather
Tools 
Cycle
The air around the earth is called the atmosphere.Weather happens in the bottom layer of the atmosphere called the troposphere.
Weather comes from two things: the sun and the moisture (wetness) in the air. They form clouds, to make rain and cause winds to blow.
In cold air in the sky, rain clouds form.
Warm air rises up from the Earth. It carries water vapor from the ocean, lakes and rivers into the sky.
Then the water vapor cools and tiny water drops form around the tiny specs of dust in the air.
They bang together and grow in size until they're heavy enough to fall. This is rain.
Clouds
There are three main types of clouds:
Cumulus clouds look like a heap of cotton balls or whipped cream.
Stratus clouds look like a flat blanket in the sky.
Cirrus clouds look like curls of white hair.
Snow
Snowflakes form when water vapor freezes into ice crystals in cold clouds.
They get heavy and fall. If the air is cold enough, the snow falls all the way to the earth without melting.
If the ground is freezing, the snowflakes stick to the ground.
When warm air and cold air get together in thunder clouds it forms static electricity. This big charge of electricity can travel to the ground or to other clouds.
Lightning is over 40,000 degrees. So a bolt of lightning makes the air around it get bigger. Thunder is the sound caused by the air growing bigger.
