AIR PRESSURE Mrs Whartons Science Class Air Air

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AIR PRESSURE Mrs. Wharton’s Science Class

AIR PRESSURE Mrs. Wharton’s Science Class

Air � � � Air consists of atoms and molecules therefore it has mass.

Air � � � Air consists of atoms and molecules therefore it has mass. Because air has mass it also have other properties such as density and pressure. Air has weight Air molecules are in constant motion and are affected by gravity. The force of this motion causes air pressure.

Density and Air Pressure � � � Density- the amount of mass in a

Density and Air Pressure � � � Density- the amount of mass in a given volume of air. Pressure- the force pushing on an area or surface. Air Pressure- is the result of weight of a column of air pushing down on an area. � The molecules in air push in all directions so it does not crush objects.

Air Pressure � � � Air pressure varies slightly over the earth’s surface, and

Air Pressure � � � Air pressure varies slightly over the earth’s surface, and variations are responsible for the weather. Low pressure is associated with storms, tornadoes and hurricanes High pressure is associated with clear and dry conditions.

Air Pressure � � � Air pressure changes with elevation As you move up

Air Pressure � � � Air pressure changes with elevation As you move up into the atmosphere, the air molecules are further apart As you move down into the atmosphere, the air molecules move closer together.

Barometers � � � Barometer- an instrument that is used to measure air pressure

Barometers � � � Barometer- an instrument that is used to measure air pressure Mercury Barometer- glass tube partially filled with mercury. Aneroid Barometer- most used in homes.

Altitude and Properties of Air � � As altitude increases air pressure decreases As

Altitude and Properties of Air � � As altitude increases air pressure decreases As altitude decreases air pressure increases As pressure decreases, density decreases As pressure increases, density increases