One day, Willa the water droplet was born.  Willa was born when 3 small things bonded together: 2 hydrogen atoms and 1 oxygen atom. That's why water is called H2O. 

Atoms are teeny, tiny particles that make up EVERYTHING on the planet, even me and you!

Willa was relaxing in her home, the Atlantic Ocean, on a hot summer day. She started to get hot and was suddenly floating up to the sky.  

Willa started to change from one big water drop to thousands of little ones, called water vapor.  Willa was now a gas rising up to the clouds through evaporation.

As she reached the clouds, she suddenly became cold and started to turn back into one, liquid water droplet.  This is called condensation.

Willa was now floating with other droplets as one big cloud.

Up in the sky, Willa and other droplets in the cloud were being blown by the wind.  They were now floating over some mountains and valleys, when the cloud started to become very heavy.    

Drip. . . drip. . . drip.   

The cloud was raining and Willa plopped down!

Willa plopped onto the side of a mountain. She started to slide down the side of it, as a stream of water, called surface runoff.    

Once she reached the grass, Willa started to be soaked into the ground and became groundwater. As she slipped through the stones and soil, she approached the root of a tree.