Rainfall Lo – To be able to explain how it rains.

By the end of the lesson: All pupils must have produced a description of how it rains. Most pupils will be able to describe relief rainfall. Some pupils will be able to explain how relief rainfall affects the pattern of rainfall in the UK.

You have 10 minutes to complete the “How it Rains” wordsearch You have 10 minutes to complete the “How it Rains” wordsearch. To give you the key words for today’s lesson.

Solution to Word search P + + + + + + + + + + + C + + + R + R I A M R A W + + O + + + + E + + + + + + + + + N + + + + + C + + + + + + + + D + + + + + + I + + + + + + + E + + + S + + + P R A I N A + N H + + + D + + + I + + I + + S A + + + + U + + + T R + + + A I + S + S + O + + C A + + + T L + E + + N + L O + T T + + I + + S + + + O O C E + + I + O + + I + + + L W E + + + + O N + + R + + S + L + + + + + + N + + + + + + S + + + + + + + + + + + + + + + + + + + + + + + + +

Why does it rain? (think back to work on the water cycle.)

Write a brief description of how it rains, use the words to help you (but they’re not in order!!) Condenses cools vapour clouds precipitation Rises heats

However, there are 3 main things that cause rainfall here in the UK…

Convectional Rain

Convectional rainfall This form of rain is common in the east of England during the summer. 1. The sun heats the ground and warm air rises. 2. As the air rises it cools and water vapour condenses to form water droplets. 3. Water droplets join together to form clouds. 4. Heavy rain storms occur.

Relief rain

Relief rainfall Relief rain is formed when air is forced to cool as it rises over relief (height) features in the landscape (hills or mountains). 1. Air is forced to rise and cools by 1°C per 100m. 2. As the water vapour in the air condenses, it forms clouds and rains. 3. The air starts to descend and begins to warm up again. 4. As air warms up, it can hold more water vapour - clouds disappear and rain stops. This side is known as a RAINSHADOW.

Frontal rain

Frontal Rainfall 1. An area of warm air meets and area of cold air. 2. The warm air is forced over the cold air 3. Where the air meets the warm air is cooled and water vapour condenses. 4. Clouds form and precipitation occurs.

Make a copy of all three types of rainfall, and explain what happens at stage 1, 2, 3 and 4 for each of them.

Copy and complete: I know how it rains. Firstly warm _____ rises because hot air is lighter than cold air. As it rises it ________. This makes condensation. We see this in the sky as ________. When the clouds get to a certain point they can hold no more _________. This is when it ______. Relief Rainfall. Relief rainfall happens when the air is forced to ______ as it hits the mountain. As it rises it_______, forms clouds and then it _______. WATER RAIN COOLS CLOUDS COOLS RAINS AIR RISE

Clouds

Cloud cover is measured in Oktas Cloud cover is measured in Oktas. Today there are _______ Oktas of cloud.

We know there are many different types of cloud, because not all cloud looks the same. You might see more than one of these types of clouds in the sky all at once.

These are the main types of cloud: Cirrus clouds are wispy, like a lock of hair, and are high up. Stratus clouds are layers, and are middle to low clouds. Cumulus means ‘heap,’ cumulus clouds look a bit like cotton wool balls Cumulonimbus clouds are tall and dense, usually resulting in rain or storms.

Golden rules… Any cloud with the word cirro or cirrus is a high cloud. Any cloud with the word alto in it is about in the middle. Any cloud with nimbo or nimbus added onto it means it is producing precipitation.

Add labels to your diagram of the clouds.

Cumulo-nimbus =Thunderheads Type of Cloud Appearance Altitude (height) Cumulo-nimbus =Thunderheads Can cause lightning, thunder, hail, strong rains, strong winds, and tornadoes Near ground up to 75,000 feet (Vertical clouds) Cirro-stratus Thin, wispy, appears in sheets. Located above thunderheads Above 18,000 feet (High-altitude clouds) Cirrus Thin, wispy, filamentous, or curly Cirro-cumulus Small, puffy, patchy and/or with a wavelike appearance Alto-cumulus Medium-sized puffy, patchy, scattered clouds - often in linear bands 6,500 - 20,000 feet (Middle-altitude clouds) Alto-stratus Thin, uniform 6,500 - 20,000 feet (Middle-Alttude clouds) Strato-cumulus Broad and flat on the bottom, puffy on top, Below 6,500 feet (Low-altitude clouds) Cumulus Puffy and piled up. Below 6,500 feet (Vertical clouds) Stratus Uniform, flat, thick to thin layered clouds will ill-defined edges Nimbo-stratus Uniform, dark, flat, low, featureless clouds that produce precipitation

alto-cumulus - Middle-level, medium-sized puffy clouds alto-cumulus - Middle-level, medium-sized puffy clouds. alto-stratus - Middle-level, layered clouds. cirro-cumulus - High-altitude, small, wispy, patchy, puffy clouds. cirro-stratus - High-altitude, thin, wispy clouds in layers. cirrus - High-altitude, thin, wispy clouds. cumulo-nimbus- Large, dense, towering clouds that cause thunderstorms. cumulus - Low, puffy clouds. fog - Ground-hugging clouds. nimbo-stratus - Low, dark, rain cloud. stratus - Low, layered, horizontal, wispy clouds with a flat base. strato-cumulus - Low clouds, broad and flat on the bottom, puffy on top (higher than cumulus and lower than altocumulus

Now answer the following questions: What are clouds? What is cloud cover measured in? What are the three main cloud types? What name do high level clouds begin with? What types of clouds does convectional rainfall cause?

Types of cloud…

Cumulus 1

2 Cumulonimbus

3                                                                                                                                                              Cumulonimbus

4 Cumulus

5 Cirrus

6 Stratus

7 Cumulus

8 Stratus

Cirrus 9

10 Cumulus

11 Cirrus

12 Stratus

13 Cumulonimbus

14 Cumulus

15 Cirrus