An Airy Cloud Story
By: Ms. Hoey
I begin my journey as a water droplet on the surface of the Earth. The Earth is also known as the blue planet due to its vast amount of liquid water on its surface. Approximately 70% of the Earth's surface is covered in water. Today we will start our journey in a lake on a hot summer day. Althought its nice here, I'm very hyper and never like to sit still.
The sun has passed its highest point in the sky and the air temperature has increased. I am beginning to evaporate ! During this processes I will change from liquid water into another phase of water known as water vapor . I begin to float higher into the sky.
I am now a part of a large moist air mass . As my new water vapor friends and I rise up within the atmosphere the air pressure decreases and we have more space to spread out and cool down. This process is called adiabatic cooling . During this process I am introduced to new friends called condensation nuclei .
Our adiabatic cooling rate is about -1 degree Celsius for every 100 meters that we rise up in the atmosphere. Our air is now completely full of water vapor. We cannot fit any more friends into this saturated air. Our air temperature is officially below the dew point temperature and another phase change is about to occur. I begin to condense onto a condensation nuclei. Together we will form a cloud!
I'm finally a cloud! I am a fluffy white cumulus cloud. There are 3 major types of clouds; stratus clouds, cumulus clouds, and cirrus clouds. I will move through the atmosphere with a push from the prevailing wind. See you next time when I get bored of the atmosphere and would like to return to the land through precipitation .
Image Resources
Chakrav, R. S. (2011, October 13). Anvil Cloud Over Bangalore, India. In Earth Science Picture of the Day. Retrieved June 26, 2012, from http://epod.usra.edu/blog/2012/06/anvil-cloud-over-bangalore-india.html
Clark, M. (2011, August 12). Summer Pileus Cloud Over Central New York State. In Earth Science Picture of the Day. Retrieved June 26, 2012, from http://epod.usra.edu/blog/2012/03/summer-pileus-cloud-over-central-new-york-state.html
Hahn, R. H. (n.d.). Pyrocumulus Cloud Over the Colorado Rockies . In Earth Science Picture of the Day. Retrieved June 26, 2012, from http://epod.usra.edu/blog/2012/06/pyrocumulus-cloud-over-the-rockies.html
Mosby, J. A. (n.d.). Heart Shaped Cloud. In Earth Science Picture of the Day. Retrieved June 26, 2012, from http://epod.usra.edu/blog/2006/02/heart-shaped-cloud.html
Nicholls, B. (2011, January 20). Lake Wanapitei Winter Evaporation Fog. In Earth Science Picture of the Day. Retrieved June 26, 2012, from http://epod.usra.edu/blog/2011/04/lake-wanapitei-winter-evaporation-fog.html
s'cool (2012). In National aeronautics and space administraion . Retrieved June 26, 2012, from http://science-edu.larc.nasa.gov/SCOOL/cumulus.html