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4th Grade Science, Weather


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High Air Pressure causes what type of weather?
nice Weather because it is less dense, less moisture
Lower Air Pressure causes what type of weather?
Stormy weather, more moisture more denser
What is a barometer?
Measures Air Pressure
Where does the world's weather occur in the atmosphere most often?
Troposphere. The lowest layer of the atmosphere.
What is the Troposphere?
The layer of air that is closest to the earth's surface.
What is the atmosphere?
Air that surrounds the earth.
What are the aspects of Weather?

air pressure
What is weather?
the condition that exist in the air.

Raining, snowing or sunny.
What are clouds?
Masses of water droplets and Ice crystals that float in the sky.
What is humidity?
the amount of moisture in the air.
What are the two temperature Scales?

What are they based on?
Gabriel Fahrenheit - based the zero as the lowest point the mercury fell during the winter in Germany, which made 32 the freezing point and 212 the boiling point.

Anders Celsius based zero as the freezing point and a 100 as the boiling point.
What is temperature?
measures the amount of heat in the air.
What is wind?
Wind is when the sun heats the land and warms the air above. The air molecules move faster, when they are heated up and that is what causes the air to move.

Also hot air rises and replace by cold air.
What is air Pressure?
Air pressure is the measure of the force of air pressing down on the earth.

air pressure depends on the density of the Air.
What affects air pressure?
The factors that affect air pressure are the factors that cause the air density, which are...


What is a front?
When two air masses meet that are different. They do not mix easily so a boundary forms.

This boundary is called a front.
What are the 4 types of Fronts?
Cold Fronts
Warm Fronts
Occuled Front
Stationary fronts
What is a cold Front?
When cold air mass meets and pushes under warm air mass.

violent storms occur.
What is a warm Front?
When warm air moves over a cold air mass.

Rain & showers, usually hot humid weather.
What is an occuled Front?
When a cold front moves faster than a warm front.

the cold front overtakes the warm front, to form an occuled front, which pushes the warm air upward.

Less severe.
stationary front?
When a warm air mass meets a cold air mass and it doesn't move.

bad weather for many days.
What is relative humidity?
Relative humidity is humidity relative to temperature.
How do you measure relative humidity?
With a Psychrometer.

Since the psychrometer uses 2 thermometers to measure the temperature, the humidity is relative to the temperature.
What holds more moisture, cold air or warm air?
warm air.
Give examples how relative humidity depends on temperature?
In warmer temperature, air holds more moisture.

In really cold days, the air hold less moisture.

Relative humidity depend on termperature.
When it is warm out, is the air pressure high or low?
When it is cold and dry, is the air pressure high or low?
How is air temperature measured?
Using a thermometer.

Either Fahrenheit or Celcius.
What are the three ways heat energy is spread throughout the atmosphere?
Define the following words?
Convection- currents of air
Radiation- through space, sunlight.
Conduction- spread through solids.
How does a thermometer work?
What is an Anememeter?
An anemometer measure the speed of the wind and the itensity of wind.
Why do winds in each hemisphere curve as they move?
Because the spinning of the earth.
What is the difference between humidity and relative humidity.
Humidity is the amount of moisture in the air.

Relative humidity is the humidity relative to the temperature.
How is relative humidity measured?
Using a Psychrometer. Which has 2 thermometer, 1 wet and 1 dry.
How does a Psychrometer work?
How does a rain gauge work?
Rain falls into the bottle and then you measure the amount of rain that fell.
3 types of clouds that bring precipitation?
4 types of precipitation
Rain, snow, sllet and hail
How does density affect the weather?
Density affect the weather by affecting the air pressure.

Less Density exerts less air pressure.
More Density exerts high
What measures air pressure?
What measures wind?
What measure relative humidity?
What measures temperature?
What measure the level of rain fall?
Rain Gauge
air is a
mix of gases
blanket of air surrounding Earth

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