Book+1+Chp.+3+lesson+1

=**3.1 Pressure**=

A. Is equal to the force exerted on a surface divided by the total area over which the force is exerted.
1. Force/ Area i. force is measured in newtons ii. SI unit = newton per sq. meter N/m squared iii. Area is measured in square meters iv. called Pascal (Pa) 1 m/m squared= 1 pa 2. To produce lower pressure by increasing the area a force acts on it.

B. Fluid Pressure
1. Fluid- a substance whose shape can easily change i. able to flow ii. exert pressure against the surfaces they touch iii. made up of molecules a.) constantly moving in all directions b.) as each molecule collides with a surface, it exerts a force on the surface 2. All of the forces exerted by the individual molecules in a fluid add together to make up the pressure exerted by a fluid. 3. Fluid pressure- the total force exerted by the fluid divided by the area over which the force is exerted. 4. Air pressure or Atmospheric Pressure- the pressure exerted by the air usually referred to as air pressure i. the force of gravity on this mass produces air pressure ii. air pressure at sea level is 10.13 N/m squared iii. Pressure from the weight of air in the atmosphere is over 100 km high
 * high pressure= nice weather
 * low pressure= bad weather
 * barometer- measures changes in air pressure

C. Variations in Fluid Pressure
1. The pressure of a fluid is the same at any given level in a fluid. 2. Air pressure decrease as elevation increases- ex. ears pop 4. water pressure increases a depth increases i. total pressure at a given point beneath the water results from the weight of the water plus the weight of the air above it. ii.deepest parts of the ocean- pressure is more than 1000 times the air pressure we experience everyday.

=Quiz: 3.1=