08 Rainfall Ppt 08

12,369 views

Published on

Published in: Technology, Business
3 Comments
5 Likes
Statistics
Notes
No Downloads
Views
Total views
12,369
On SlideShare
0
From Embeds
0
Number of Embeds
24
Actions
Shares
0
Downloads
796
Comments
3
Likes
5
Embeds 0
No embeds

No notes for slide

08 Rainfall Ppt 08

  1. 1. Climate & Weather RAINFALL
  2. 2. Is this a common sight in Singapore?
  3. 3. <ul><li>Rainfall refers to the amount of rain that an area receives over a period of time </li></ul><ul><li>Rainfall is necessary to provide us with our supply of water </li></ul><ul><li>Long periods without rain will cause droughts to occur. </li></ul><ul><ul><li>Example: Sahel Desert (Africa) </li></ul></ul><ul><li>Persistent or continuous heavy rain may lead to floods that can damage property and claim lives. </li></ul><ul><ul><li>Example: Low lying areas of Bangladesh </li></ul></ul>Effects of Rainfall
  4. 4. Land that is terribly dried up because of the lack of rain
  5. 5. High amounts of rainfall results in flooding
  6. 6. Measuring Rainfall <ul><li>Rainfall is measured using an instrument called a rain gauge </li></ul>Funnel Copper cylinder Glass Bottle Outer Casing
  7. 7. Measuring Rainfall <ul><li>It consists of a funnel that collects and channels rainwater into a container </li></ul><ul><li>The water collected in the glass jar is then poured into a measuring cylinder to show the reading </li></ul><ul><li>It is measured in millimetres (mm) or centimetres (cm) </li></ul>
  8. 9. Measuring Rainfall <ul><li>It is represented in the form of vertical columns in climograph </li></ul><ul><li>It should be placed in an open area where there are no obstructions to block the rain </li></ul>
  9. 10. Formation of Rain <ul><li>When the Sun’s rays heats up the surface of the Earth, the air above it is warmed up. </li></ul><ul><li>This causes the water from the land and oceans, seas and lakes to change into water vapour. This process is called evaporation </li></ul><ul><li>Plants also give out water vapour into the air through a process called transpiration </li></ul>
  10. 11. Formation of Rain <ul><li>As the warm air rises, it begins to cool </li></ul><ul><li>As soon as the air cools below a certain temperature, the water vapour that it is holding changes into very small water droplets </li></ul><ul><li>This process is called condensation </li></ul>
  11. 12. Formation of Rain <ul><li>These tiny water droplets will remain suspended in the air </li></ul><ul><li>When more water droplets are gathered together, clouds are formed. </li></ul><ul><li>When the droplets of water become too big and heavy to float in the air, they will fall to the ground as rain. This process is termed precipitation . </li></ul>

×