Why doesn't it hurt when it rains??

1. Why is rainfall important?

In your groups, discuss the reasons why rainfall is important? Think back to your work on decision makers. How does rainfall affect human activity? How does it affect the natural environment and ecosystems?

2. Why does it rain? - what are the ingredients for rainfall?

Both of the diagrams on the left show the basic elements that are needed for rainfall to occur. Study both diagrams carefully and describe the ingredients and processes that go together to make rainfall in your own words.

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2. What are the different types of rainfall?

Watch both of these video clips VERY CAREFULLY. You are going to be using them to help you draw/annotate your own diagrams of each of the four different kinds of rainfall that are explained!

1) Explain how clouds form in your own words including all of the following words/phrases:

• swirling mass
• water vapour
• water molecules
• particles of dust and pollen
• collide
• bigger and heavier
• 1000000
• raindrops
• gravity

2) List the THREE kinds of rainfall that the clip lists

3) This clip includes a fourth kind of rainfall. What is it? Add it to your list!

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3. Rainfall diagrams

rainfall_diagrams.pdf
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Use the information from the videos above to make sure that you have four fully annotated diagrams showing each of the four types of rainfall below. The labels have been listed for each diagram but you will need to sort them into the right order and position them properly on your own diagrams. 

Relief Rainfall (Orographic rainfall)

• warm moist air
• air cools
• air sinks and warms
• air forced to rise over hills/mountains
• evaporation
• air cools
• rain shadow (area with low rainfall as all the moisture has gone)
• condensation forms clouds
• precipitation

Convectional rainfall

• air cools as it rises
• hot sunny conditions
• the ground heats the air above it
• condensation forms clouds
• sun heats the ground
• air rises because hot air is less dense
• precipitation

​Frontal rainfall

• air cools as it rises
• front (where two air masses meet)
• cooler air (more dense)
• warmer air (less dense)
• condensation forms clouds
• warm air is forced to rise over the cooler air
• precipitation

Low pressure rainfall (depressions)

• condensation forms clouds
• air cools as it rises
  
• precipitation
• air rises in the centre of a low pressure system

4. Rainfall mime!

​Your group is going to work as a team to create a mime/dance which will explain your kind of rainfall to the rest of the class. You MUST include:

• Why the air is moist
  
• What causes the air to rise
  
• Why the air cools
  
• How and why clouds form
  
• Anything specific to your kind of rainfall
  

ONE person is allowed to speak but the rest of the group need to use your bodies to show/explain the processes which make it rain! PLANNING TIME = TEN MINUTES MAXIMUM!!

5. Homework practical task - make it rain

MATERIALS:

• glass mayonnaise or canning jar
• plate
• hot water
• ice cubes

PROCESS:

• Pour about two inches of very hot water into the glass jar.
• Cover the jar with the plate and wait a few minutes before you start the next step.
• Put the ice cubes on the plate.

EXPLANATION:
What happens? The cold plate causes the moisture in the warm air, which is inside the jar to condense and form water droplets. This is the same thing that happens in the atmosphere. Warm, moist air rises and meets colder air high in the atmosphere. The water vapour condenses and forms precipitation that falls to the ground.

DOCUMENT:
Photograph, sketch or even video your experiment and annotate or do a voice over which explains the processes occurring and connecting back to relief, convectional and frontal rainfall.

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