2. Transmitting Pressure in a fluid. 11-2

3. Pascals Principle In 1600 a French mathematician stated that “When force is applied to a confined fluid an increase in pressure is transmitted equally to all parts of that fluid”. This is known as Pascal’s Principle.

4. A force pump causes the fluid to move from one place to another by increasing the pressure in the fluid.

5. Force Pumps For example: tube of toothpaste, ketchup bottle, your heart

6. Using Pascal’s Principle Page 356 for graphic. What does the graphic show? That when you increase the area of the piston you are multiplying the force.

7. Hydraulic Systems Multiplies a force by applying the force to a small surface area. The increase in pressure is then transmitted to another part of a confined fluid, which pushes on a larger surface area. Air in the System It is important that a hydraulic system contains no air bubbles. You may have heard about the need to "bleed the air out of the brake lines" of you car. If there is an air bubble in the system, then the force applied to the first piston gets used compressing the air in the bubble rather than moving the second piston, which has a big effect on the efficiency of the system. › Introduction to How Hydraulic Machines Work › The Basic Idea › How Log Splitters Work › Large Hydraulic Machines › Skid/Loaders › Dump Trucks › MPEG Videos › Lots More Information!Introduction to How Hydraulic Machines WorkHow Log Splitters WorkLarge Hydraulic MachinesSkid/LoadersDump TrucksMPEG VideosLots More Information!. >Prev Page Intro Next Page Table of Contents: › Introduction to How Hydraulic Machines Work › The Basic Idea › How Log Splitters Work › Large Hydraulic Machines › Skid/Loaders › Dump Trucks › MPEG Videos › Lots More Information!Introduction to How Hydraulic Machines WorkHow Log Splitters WorkLarge Hydraulic MachinesSkid/LoadersDump TrucksMPEG VideosLots More Information! Rate this Article! Join HSW!Join HSW! || Newsletter || Suggestions || Link to HSW || Hiring Win! || Store || About Us || Contact Us || Privacy || Home Frequently Asked Questions || Advertising Copyright © 1998-2002 Howstuffworks, Inc. All rights reservedNewsletterSuggestionsLink to HSWHiring Win!StoreAbout UsContact UsPrivacyHome Frequently Asked QuestionsAdvertising

8. Hydraulic System Used on fire truck ladders, brake systems in cars,and sea stars.

9. Floating and Sinking 11-3

10. Buoyancy Buoyant forces act on submerged objects. The buoyant force acts in the upward direction, against the force of gravity, so it makes the object feel lighter.

11. Buoyancy Fluid pressure is exerted in all directions on a submerged object. Since pressure increases with depth, the upward pressure is on the bottom of an object is greater than the downward pressure on the top. The net force acts upward and is called buoyant force.

12. Archimedes Principle The buoyant force on an object is equal to the weight of the fluid displaced by the object.

13. Sinking If the weight of the object is greater than the buoyant force the object sinks. It only sinks far enough to displace a volume of liquid =to its own weight

14. Density Density is mass/volume. An object that is more dense than the fluid in which it is immersed sinks. An object that is less dense than the fluid in which it is immersed floats. Density of water = 1.0 g/mL

15. Floating If the weight of the object is less than the buoyant force,

16. Applying Bernoulli’s Principle Figure 7.3: Lift of an aircraft wing

17. Bernoulli’s Principle The pressure exerted by a moving stream of fluid is less than the pressure of the surrounding fluid. PIRA 2C20.30 Bernoulli's Principle: Floating Tetherball.

18. Objects in flight Apply Bernoulli’s Principle by their shapes. Different shapes cause the air to move at different speeds above and below them.

19. Airplane wings? They are shaped so that the air moves faster over the top of the wing and pressure pushes the object upward.