Precipitation Essential Questions. What is Precipitation? How is precipitation formed? What are the processes involved in forming precipitation? What are the different types of Rainfall? Why are there different types of rainfall?

What is Precipitation? Precipitation is the primary mechanism for transporting water from the atmosphere to the surface of the earth. There are several forms of precipitation, the most common of which for the United States is rain. Other forms of precipitation include; hail, snow, sleet, and rain.

Rain Sleet SnowHail

Conditions necessary for rain to form Presence of water / water vapour Heat – evaporation Cooling – dew point – condensation Cloud formation

Processes involved in the formation of rain

Liquid state Gaseous State

Types of rainfall 1.Convectional Rain 2.Relief Rain or Orographic Rain

Heat rays from the Sun The ground absorbs the Sun’s Heat rays and becomes heated Heat is radiated from the ground to the air Warm Air Rises together with water vapour Warm air cools down and water vapor condenses to form water droplets forming clouds. The cloud become saturated with water droplets. Rainfall takes place called Convectional Rain Convectional Rain

Relief or Orographic Rain

Ocean Prevailing Wind Moist & warm air from the ocean (20 o C) High mountain Moisture condenses as the air cools (7 o C) at high altitudes (2000m) to form clouds. Clouds become saturated with water Windward side of Mt Leeward side of Mt Cool & dry air descends the leeward side of mountain, resulting in a dry and warm climate

Questions? 1.What is an important factor necessary for Convectional and Relief rain to form? 2.What type of rain would Singapore commonly experience? 3.Other than this type of rain, what other forms of rain does Singapore experience? (Hint, Nov and Dec are generally wetter, why?) 4.Name some locations where Relief rain is commonly experienced? (Hint Mountain ranges that face the oceans)

My journey in becoming a self-regulated learner? Do you know what is the learning target for this lesson? ( Do you know what your need to understand – knowledge & skill) Can you go thru the slides and think about what you are reading and listening? Do you have questions as you learn? Do you know what you have learnt, un-learnt and re-learn?

Winds Essential Questions What is wind? How is wind formed? What are the different types of wind? What are the different scales of wind?

What is wind? Parcel of Cold air (high pressure) sinks as it is denser Parcel of Warm air (low pressure) Warm air rises (lighter/Less dense) Wind is simple the flow of a huge amount of air, usually from a high pressure area to a low pressure area.

How is wind formed? You may use annotated diagrams to explain. Some points to get you started: 1.Rate of heating of solids and liquids? 1.1What experiments can you design to show the differing rates of heating of solids and liquids? 2. Warm air rises… Cold air …. 2.1 Design an experiment to prove that warm air rises and cold air sinks. Develop an explanation for this.

What are the different types of winds? There are mainly ….. 1.Local Winds 2.Planetary / Global Winds

What are Local Winds? Local winds are those that are created as a result of scenery such as mountains, vegetation, and water bodies. They usually change very often and the weather forecast people talk about this kind on the TV everyday. They can move from mild to extreme winds in just hours. Good examples of local winds are sea breezes and land breezes, and mountain and valley breezes. Local winds cover very short distances and are on a small scale.

Formation of Sea Breeze

Land gets Heated Air gets heated and rises The Sea (liquid) is a poorer conductor of heat and thus it is cooler. The air above the sea is also cooler compared to the air above the land As it is less dense (low pressure) Cool air is denser (high pressure) and sinks to stay close to the surface of the water HP LP Sea Breeze

Now it’s your turn With the help of an annotated diagram, explain how land breeze is formed. (p.51?)