Activities

1. What causes clouds to form?
   
   
2. What are clouds made of? What causes precipitation to fall in different forms (such as rain and snow)?

3. Describe the three major categories of clouds: cumulus, stratus, and cirrus. Include information on its appearance, altitude, and forecasted weather.
   
   
4. Describe high and low pressure systems, including the weather they bring.

5. How is water vapor related to humidity? How does temperature affect this?
   
   
6. What is wind and how does wind assist with predicting weather?

Answer Key/Rubric

1. Clouds form when air rises, cools and condenses into water droplets, or ice crystals that form clouds.
   
   
2. Clouds are made of tiny water droplets or ice crystals.  The type of precipitation that falls depends on the temperature of the air it passes as it nears the surface.  Other factors may include the temperature of the air directly below the cloud. If the air is above freezing, it will be rain, and below freezing will be snow.  In some cases, such as hail, the stones form directly in the cumulonimbus clouds, and reach the earth in this solid form.

3. Acceptable responses may include, but are not limited to:

• Culumus- puffy white clouds, form low in the atmosphere (usually around 3,000 ft.), bring fair weather
• Stratus- layered gray clouds that resemble a blanket, form around 6,000 ft., usually produce a drizzle (or snow)
• Cirrus- wispy/feathery white clouds, form high in atmosphere (up to about 20,000ft.), generally produce fair weather

4. Sample response: High pressure systems occur where the atmospheric pressure is higher than the surrounding area.  These systems usually being calm weather and clear skies. Low pressure systems occur when the atmospheric pressure is lower than the surrounding area. Due to this instability, these systems generally produce clouds, precipitation, and tropical storms.

5. Sample response: Humidity measures the water vapor in the air.  Relative humidity measures the percent of water vapor in the air compared to the amount it can hold at that temperature.  The warmer the temperature, the more water vapor it can hold. The cooler the air, the less water vapor it can hold.
   
   
6. Sample response: Wind is caused by the difference in air pressure. The greater the difference, the more intense the speeds of the wind, which is measured in knots.  Air moves from areas of high pressure to low pressure.  Given this movement, winds are able to move air masses around.  If wind passes over bodies of water and picks up moisture, precipitation is likely to occur. If it passes over dry land, then dry weather can be predicted.