What is weather
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Transcript of What is weather
What is
weather?
Weather• Weather it is the condition of the atmosphere
at a particular time and place .
What can cause the changes of weather?
• Weather variables:
1) Temperature
2) Wind
3)Moisture
4)Precipitation
How to predict weather ?
1)Weather Balloons 2) Weather satellites
• 3)Doppler radar
It IIt can detect :1)Precipitation2)Wind direction3) Wind speed
Insolation • It is the amount of sun energy reaching the
Earth at a given time and place
What is the angle of insolation?
• a measure of how high the sun is in the sky • measured from the horizon up to the position of the sun
What happens as the angle increases or decreases?
• As the angle of insolation increases, intensity increases. (heat concentrated in smaller area.)
• As the angle of intensity decreases, heat is spread out over a larger area.
Low angle: Less absorbedHigh angle: More absorbed
• Intensity of insolation varies over the Earth because of the curvature of the Earth.
Earth
Where is intensity the greatest and lowest?
• Intensity greatest near the Equator.
– Sun’s rays are direct
• Intensity low at the poles
At what time is the angle and intensity of insolation greatest?
•The noon sun has the greatest angle of insolation.
How to measure angle of insolation ?
• WE can measure ion angle of insolation
Why does the angle of insolation change between midday and
evening?
The angle of insolation decreases because the Earth’s rotation ,and the air temperature usually decrease
Measuring Temperature
Pressure• It is the weight of air pressing on a unit area.
• The difference of air pressure is due to unequal heating of the Earth.
• Warm air masses have fewer air molecules than cold air masses.
What is the relation between temperature and pressure ?
As the temperature increases the air particles are far away from each other decreasing the pressure As the temperature increases the pressure decreases
Air Pressure• Air Pressure is a
measure of the force of the air pressing down on the earth’s surface
Air Pressure can vary at any particular
point on the Earth depending on the
density of the air
Density = mass / volume
Challenge:
Solution:
Results and
Explanation:
How can you stop the leak in this soda can?
Title: Activity 2. Stop the Leak Date: Feb. 2010
Summary:
Convection Cell-Suppose air in an area is cool and under high pressure
-If a near by place is warmer and at a lower pressure
-The air will move from high pressure area to a low pressure area .
This is called “Surface wind”
• What do you think can increase the intensity of the wind ?
• As the difference in pressure increases the wind intensity increases
• Unequal heating and cooling of air results in difference in pressure
• Where warm air will move
• Up and cold air moves down making a circular pattern of rising and sinking air and wind called “Convection cell”
Sea Breeze
Land Breeze
Instruments used to measure ”Wind and Pressure”
1)Anemometer
A device used to measure wind speed .
The cups spin faster as the wind blow faster
2)Weather Vane
It is used to measure wind direction . It ‘s a movable arrow that points in the direction the wind blowing .
3)Barometer
Measures surrounding air pressure against standard air pressure