003 - How does it Rain?

Factual Question

How does it rain?

Key Terminology

            • Precipitation
            • Convectional
            • Frontal
            • Relief/topographic
            • Prevailing
            • Rain Shadow


Throughout this lesson we will learn what all of these words mean, but if you are still unsure of them by the end of the lesson then click on the useful link below to review them.


Useful Link

Activity One - Watch - What is rain?

Rain is an essential element for life but how is it caused? Watch the YouTube clip below and answer the following questions about how rain forms.


  1. How does the water get in to the atmosphere?
  2. Why does rain form?
  3. What is frontal rain like? Where does it occur?
  4. Describe what topographic or relief rain is.

Activity Two - The different causes of rainfall

Rain is caused by moist air rising and cooling. The three types of rainfall produced in this way are relief, convectional and frontal. Clouds are made up of small drops of moisture called cloud droplets. Clouds form when moist air rises, cools and changes into cloud droplets. This is called condensation.


  1. Copy out the sentence below and fill in the blanks using the words in the box. Then copy the diagram showing the process of rainfall and label what is happening.

Fill in the blanks

The process of rainfall is always the same air _______, cools, _______ and precipitates.

condenses rises

From:wikimedia.org

Image Two - How it rains?

2. Relief rainfall occurs when moist air is forced to rise over mountains. As the air rises it will cool and then the rain making process will occur. Copy the diagram

below and add the phrases in the box to annotate what is happening.

Relief Rainfall Phrases

Air sinks giving drier weather conditions. This is known as the rain shadow.

Prevailing wind from the south-west picks up moisture from the sea.

Air is forced to rise and cools over the mountains. Cloud forms and it rains.

3. Copy out the diagram below and annotate how convectional rainfall occurs using the information box.


Information

Convectional rainfall occurs mainly in the summer when the sun is hottest.

Evaporation of moisture from the earth rises high into the sky, cooling quickly as it does.

The result is huge tower-shaped cumulus clouds and rainfall.

Thunder and lightening may also occur.

Thunder and lighting occurs when electrical charges are formed within the cloud.

4. Read the article link below about frontal rainfall. Describe how frontal rain occurs in no more than 5 sentences.