PRESSURE

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PRESSURE!

• Chapter 10 Section 1

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Pressure

• To Press
• 1) Pressure and Area
• The amount of pressure you exert depends on the
• AREA over which you exert a FORCE.
• The larger the surface area, the less pressure
  exerted.
• 2) Calculating Pressure
• Pressure Force/Area
• What is the SI unit for Force? For Area?
• SI Unit for Pressure Pascal or N/m2

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Why is it good to walk in the snow with
snowshoes? What would happen if this fellow wore
running shoes?
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The amount of pressure you exert depends on the
area over which you exert a force.
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Fluid Pressure

• As particles in a fluid (air, water, oil) collide
  with each other and with a surface, they exert a
  force on the surface.
• All the forces exerted by the individual
  particles COMBINE to make up the pressure exerted
  by the fluid.

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• 1) Air Pressure
• Air is fluidand fluid is mass.
• Force of gravity pulls down on mass of air,
  therefore, the air has weight.
• The weight of the air is the force that produces
  air pressure. A.K.A atmospheric pressure

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Atmospheric Pressure decreases as you go higher.
There are less air mass above you.
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• 2) Balanced Pressure
• Pressure is exerted equally in all directions.
• Why arent you crushed by the air around you?
• Do you think you have fluids inside you? What
  about outside of you?
• See overhead for Picture!

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Your ears pop when you move to a higher
elevation. Ears are balancing the pressure
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• 3. Water Pressure Depth
• Water pressure increases as depth increases.
  More water mass above you.
• In addition, air in the atmosphere pushed down on
  the water.

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Barometers measure Atmospheric Pressure