The Cloud Cookery
How to Make a Cloud
Have you ever wondered how clouds form? Well its quite simple! Clouds form from the condensation or freezing of water vapor. Want to see for yourself? Youll need an adult for supervision and the following household items: warm water metal tray ice see-through jar match Condensation occurs when a gas (water vapor in this activity) changes into a liquid (the cloud). Water vapor condenses onto a surface when cooled. For instance, take a cold water bottle outside on a warm day, and notice that water droplets form on the surface. This is CONDENSATION and clouds form the same way. Heres how to make your own cloud. Procedure: 1. Fill a jar with 2 inches (5cm) of warm water and stir. 2. Ask an adult to light a match, blow it out and drop it into the jar. 3. When the smoke clears, place an ice-filled metal tray on top. 4. Watch carefully and a cloud will form near the top of the jar.
So what exactly happens?
Observe clouds and help NASA investigate our changing planet!
The warm liquid water forms water vapor. This process of changing liquid water to gas is called EVAPORATION. As the water vapor rises and nears the ice-filled tray, the vapor cools. The smoke particles provide a surface for the water to condense. Did you realize that evaporation is the opposite of condensation? If you remove the metal tray, the cloud will disappear as it mixes with the warmer surrounding air. The same events occur in our environment. Evaporated water condenses to form clouds which may later produce rain. The production of rain is referred to as PRECIPITATION. Together, EVAPORATION, CONDENSATION and PRECIPITATION play an important role in the WATER CYCLE.
Ever wonder how clouds got their names? Well you may be surprised to find out!
In 1803 Luke Howard used Latin terms to classify four main cloud types. Cumulus means pile and describes heaped, lumpy clouds. Cirrus, meaning hair, describes high level clouds that look wispy, like locks of hair. Featureless clouds that form sheets are called Stratus, meaning layer. The term Nimbus, which means cloud, refers to low, grey rain clouds. Alto is used to describe mid level clouds. Finally, convective clouds have a vertical development extending through large portions of the atmosphere.
There are specific cloud types associated with the low cloud levels. There are low, mid and high level cloud types.
Cloud Type
Cloud Observation Basics
Low Level
Cloud Type
Fog Nimbostratus Cumulonimbus Stratus Cumulus Stratocumulus
Three levels of clouds have been identified based on the altitude of a clouds base.
Cloud Level
Cloud Cover
Clear Partly Cloudy Mostly Cloudy Overcast (0% - 5%) (5% - 50%) (50% - 95%) (95% - 100%)
Visual Opacity
Opaque Translucent Transparent
Determination of the amount of cloud cover is done by estimating the percentage of the sky covered with clouds.
Cloud Cover
The thickness of a cloud determines the amount of light being transmitted through the cloud. Shadows often provide a clue.
Visual Opacity
Clouds are powerful agents of global change. They affect the temperature of the Earth and play a large role in controlling our climate. The study of clouds takes teamwork and NASA scientists need students all over the world making ground truth measurements. Ground truth measurements of clouds are land-based observations to compare with satellite retrieved data. Satellites are an important tool for cloud studies and making sure satellite instruments are accurate is very important. Ground truth observations made by SCOOL participants help NASA scientists test the accuracy of satellite instruments.
CERES S'COOL Project http://scool.larc.nasa.gov
