Presentation on theme: "Weather... You can’t see me, but you feel me, you can’t touch me, but I can touch you. I have been called the “Breathe of the Gods”, or the killer and."— Presentation transcript:
Weather... You can’t see me, but you feel me, you can’t touch me, but I can touch you. I have been called the “Breathe of the Gods”, or the killer and giver of life, gentle and fierce, friendly and enemy, angry and happy. The Native Americans called me Moriah, and Snow Eater (Chinook). The Japanese call me Kaze and in Russia I am called Veter. I can shatter homes, or wake a child from a peaceful sleep or bring relief in times of need. I can spread the most dreaded diseases or bring a welcome freshness. What am I?
Weather is.... The current state of the atmosphere...what is happening right now
The Earth’s Atmosphere
Main points to remember as we learn about weather: The sun warms the earth’s surface and therefore all the air above the surface The earth is warmed most at the equator and least at the poles---why? The air above land is warmed more quickly than air above water. Warm air expands and rises, creating an area of low pressure; cold air is heavy and sinks, creating an area of high pressure
High Pressure and Low Pressure
Winds and Air Pressure
Remember… Rising air and descending air produce different kinds of weather
Depressions A Depression is an area of Low Atmospheric Pressure. Depressions are also known as Cyclones. Depression often pass over Ireland. Depressions bring wet and windy weather. This is why we receive lots of rain.
Anticyclones An anticyclone is an area of high pressure. Anticyclones bring clear sunny weather. There are few clouds and a gentle breeze.
Fronts When two air masses meet they do not mix very well because of their different temperature, pressure and humidity. Where the two air masses meet is called a Front. We will look at two types of Fronts, a Cold Front and a Warm Front.
Fronts: the boundary between 2 air masses Warm Front: warm air slides over departing cold air- large bands of precipitation form This is the symbol on a map for a warm front
Cold Fronts Cold air pushes under a warm air mass. Warm air rises quickly=narrow bands of violent storms form This is the symbol for a cold front
Occluded Front 2 air masses merge and force warm air between them to rise quickly. Strong winds and heavy precipitation will occur This is the weather map symbol for an occluded front
Reading a weather map ISOBAR= connects areas of equal pressure BAR comes from BARometric pressure
Reading a weather map... Isotherm: Connects areas of equal temperature; therm means temperature
Understanding the weather Rte player – weather– weather Weather charts
The water cycle Water: a renewable resource
The Water Cycle Keywords 1.Evaporation 2.Condensation 3.Cloud 4.Percipitation 5.Run Off
Water Water is a basic natural resource needed to maintain human and animal life and to grow food It is a renewable resource
The Water Cycle Run Off
Important terms 1. Evaporation – Water transferring from the ground into water vapour in the air. 2. Condensation – Water vapour in the air turning back into a liquid.
3. Cloud – Water droplets are held in the air in the form of clouds. 4. Precipitation – Water that falls to the ground in the form of Hail, Rain, Sleet, or Snow. 5. Run – off – Water running over the ground back to the sea.
Activity Draw and explain the water cycle into your copies. Water cycle song http://www.youtube.com/watch?v=o3BVa7 PH_JE&feature=youtube_gdata_playerhttp://www.youtube.com/watch?v=o3BVa7 PH_JE&feature=youtube_gdata_player Water Cycle song
Clouds Clouds are made when water vapour condenses into tiny droplets. There are many different types of clouds. The most common types of clouds are; 1.Cirrus Clouds 2.Cumulus Clouds 3.Stratus Clouds
TYPES OF CLOUDS Cirrus Clouds: wispy, feathery clouds Form only at high levels, therefore are made of ice crystals
Types of Clouds Cumulus Clouds: are puffy white cotton ball looking clouds
Cumulonimbus Clouds These are thunderstorm clouds
Types of Clouds Stratus Clouds: clouds that form in flat layers- cover all or most of the sky and are low level clouds
Rainfall Precipitation means hail, rain, sleet or snow. Rain is the most common type of precipitation. Rain occurs when warm air is forced to rise. As the warm air rises it cools. Cold air cannot hold as much water vapour as warm air, so condensation occurs. Clouds are formed and rain occurs. There are 3 different types of rain, because there are 3 different reasons why warm air is forced to rise. 1.Relief rainfall 2.Frontal (cyclonic) rainfall 3.Convectional rainfall
Relief Rainfall Relief rainfall occurs when; -Warm moist air moves in from the sea. -It hits a mountain range at the coast and is forced to rise. -It cools as it rises. -Condensation occurs, clouds form and it starts to rain.
Frontal Rainfall Frontal rainfall occurs when; –Warm and cold air masses meet at a Front –The warm air mass moves up over the cold air mass. –The warm air cools and condensation takes place. –Stratus clouds form and rain occurs.
Convectional Rainfall Convectional rain occurs when; –The sun shines on the land and heats up the air above it. –The heated air rises quickly. –As it rises it cools and condensation occurs. –Cumulus clouds are formed and heavy rain occurs.
The Weather When we talk about the weather we usually talk about the following things. 1.Temperature 2.Precipitation (rain etc) 3.Sunshine 4.Wind speed 5.Wind direction 6.Atmospheric pressure 7.Humidity All of these different aspects of the weather can be measured. There are different weather instruments to measure each thing. These instruments are usually in a weather station.
Temperature Temperature is measured using a Thermometer. It is measured in degrees Celsius (°C). Lines on a weather map showing areas of equal temperature are called Isotherms.
Temperature You need to know how to calculate the; 1. Mean Temperature 2. Temperature Range Mean Temperature: Add all the monthly temperatures, then divide by 12. Temperature Range: Take the lowest temperature away from the highest temperature. MonJanFebMarAprMayJunJulAugSeptOctNovDec Mean Monthly Temp 101315171821232821151211
Precipitation Precipitation is measured using a Rain Gauge. It is measured in millimetres. Lines on a map showing areas of equal precipitation are called Isohyets.
Sunshine Sunshine is measured using a Campbell Stokes sunshine recorder. Sunshine is measured in Hours per day. Lines on a weather map showing areas of equal sunshine are called Isohels.
Wind We can measure 3 things about the wind. Wind Speed – Using an Anemometer. Wind Direction – Using a Wind Vane. Wind Strength – Using the Beaufort Scale
The Beaufort Scale The Beaufort Scale describes the effect the wind has on the landscape. Wind strength is divided into 12 forces. The Beaufort Scale was invented by an Irishman.
Atmospheric Pressure Atmospheric pressure is measured using a Barometer. It is measured in millibars. Lines on a weather map showing areas of equal pressure are called Isobars.
A Barograph can also be used to measure atmospheric pressure
What is Humidity? Humidity is the amount of moisture in the air. It can be measured in various ways, but the most usual is to describe it as 'relative' humidity. This is expressed as a percentage. A relative humidity of 100% means the moisture content of the air is the maximum possible at any particular temperature. The hotter the air, the more moisture it can hold.
Humidity Humidity is measured using a Hygrometer. A common type of hygrometer is a wet and dry bulb thermometer. It is expressed as a %. 100% is the maximum.
What you have learnt 1.Weather associated with high and low pressure. 2.Fronts 3.Reading weather charts 4.Water cycle 5.Rainfall 6.Measuring weather