Print and copy this worksheet for use in the classroom.

To learn what effect clouds have on the temperature at the Earth's surface.
 

• Thermometers
• Cloud chart

Use a thermometer in a shady location about a metre above the ground well away from buildings to measure the temperature on clear and cloudy days over several weeks.

Along with the temperature measurement, note the time and date.  You should take measurements during both day and night.

Use a cloud chart (photos of different cloud types) to record the type of cloud present.

Estimate the fraction of the sky covered by cloud.  An easy way is to observe how many eighths of the sky is cloudy.  For example, if half the sky contains clouds, you would describe the cover as 4/8.  If clouds occupy only a fraction of the sky, you would write 1/8.
 

Answer the following questions in the space provided.

1. Examine your data to see if you can work out what effect clouds have on surface temperatures.
   
   
   
   
2. Are there some types of clouds that seem to increase surface temperatures?  Which types?
   
   
   
   
   
   
   
   
3. Are there some types of clouds that seem to lower surface temperatures? Which types?
    
    
    
    
    

Explanation

Clouds are named according to their height, shape and colour.  There are low clouds (below 2 kilometres), medium clouds (2 -7 kilometres) and high clouds (above 7 kilometres).  There are also clouds that stretch long distances through the atmosphere.  Because the air is so cold, high clouds are normally made up of tiny ice particles.

Cirrus are high, white, feathery, hair-like clouds.  They are made up of ice crystals and don't bring rain.

Clouds with a woolly appearance are called cumulus.  Sometimes they are small low-level clouds.  They can also be present during thunderstorms, reaching heights of 15 kilometres.  Cumulus clouds often produce rain.

Stratus are low grey clouds.  If the air is very still, tiny water droplets can fall to the ground as a drizzle.

In general, high clouds warm the Earth's surface and low clouds have a cooling effect.

This activity is courtesy of
the Cooperative Research Centre for Southern Hemisphere Meteorology

For some fun you could have a go at the Mr McCloud Cloud Quiz.