Fluid Pressure and Hydraulics
Balanced and Unbalanced Forces
• If the inside of a container experiences lower pressure than the outside, the container will collapse.
Example – Drinking juice in a drinking box.
• If the inside pressure of a container is higher than the outside, the container will expand.
Example – Carrying a container of pop on an airplane. Once in the air the bottle expands slightly and you need to release the pressure.
• The higher the elevation the lower the air pressure this happens because the higher the elevation the less dense the air.
• At sea level, the air that surrounds us presses down on our bodies at 14.5 pounds per square inch. You don't feel it because the fluids in your body are pushing outward with the same force.
• Dive down into the ocean even a few feet, though, and a noticeable change occurs. You can feel an increase of pressure on your eardrums. This is due to an increase in hydrostatic pressure, the force per unit area exerted by a liquid on an object.
• The deeper you go under the sea, the greater the pressure of the water pushing down on you.
Hydraulics
Hydraulic Systems
• Hydraulics are the study of pressure in liquids.
• Devices that transmit forces through a liquid to move something, due to pressure, are called hydraulic systems.
Hydraulics to transport fluids
• Liquids under pressure flow away from the pressure source.
• Hydraulics can be used to transport fluids over long distances.
• Pumps provide the pressure source to move the fluids.
• Moving gas, water and oil are done with pipes and hydraulics.
We use hydraulics in car bakes, airplanes, and heavy equipment!