Bell Ringer 2-11-10 Fill in the blanks. (pg. 372) -Yes you have to write it all out! The word pressure is related to the word ______. It refers to a ____ exerted on a surface. Due to the force of ___, your feet exert a ___ on the ground in the form of ___.

Bell Ringer 2-11-10 Fill in the blanks. (pg. 372) -Yes you have to write it all out! The word pressure is related to the word press. It refers to a force exerted on a surface. Due to the force of gravity, your feet exert a force on the ground in the form of pressure.

Air Pressure

Chapter 11.1 Pressure

Pressure Pressure decreases as the area over which a force is distributed increases. P. 373

Pressure formula Pressure is equal to the force exerted on a surface divided by the total area over which the force is exerted. Pressure = force area

SI Units Force  Newtons (N ) Area  square meters (m2) Pressure Newton per square meter (N/m2). This unit of pressure is also called the Pascal ( Pa). 1 N/m2 = 1 Pa

Fluid Pressure A fluid is a material that can easily flow. What causes fluid pressure??? As each particle in a fluid collides with a surface it exerts a force on the surface. All the forces exerted by individual particles in a fluid combine to make up the pressure exerted by the fluid.

Air pressure Air exerts pressure because it has mass. Because gravity pulls down on air, it also has weight.

Variations in Pressure As your elevation increases, atmospheric pressure decreases. Ex: riding up elevator Water pressure increases as depth increases. Ex: bottom of the ocean

High Pressure vs. Low Pressure High Pressure  anticyclone – air descends (pretty weather) Low Pressure  cyclone – air rises (bad weather)

Measuring Pressure A barometer is a tool that measures pressure.