1. Archimedes’ and Pascal’s Principles

2. Archimedes’ Principle

3. Archimedes’ Principle
Archimedes' principle states that the apparent loss in weight of a body that is totally or partially immersed in a liquid is equal to the weight of the liquid displaced. Archimedes supposedly formulated this principle after stepping into a bath and watching it overflow. According to legend, he became so excited that he ran out into the street naked shouting "Eureka! Eureka" ("I've found it! I've found it!")

4. Archimedes Principle Volume: space taken up by an object
The volume of fluid displaced (pushed out of the way) by an object equals the volume of object.
Buoyant Force – upward force exerted by fluid
The buoyant force on an object equals the weight of the fluid displaced by the object.
Archimede’s Principle Demo:
Horse & Bargehttps://

5. Archimedes Principle
The buoyant force on an object equals the weight of the fluid displaced by the object. Buoyancy is the upward force exerted by fluids.

6. Density Density: ratio of mass to volume
If two objects have same volume, which one has greater density: one with more mass OR one with less mass?
If two objects have same mass, which one has greater density: one with more volume OR one with less volume?

7. Float or sink or???
If the buoyant force > weight, (less dense) the object will float at surface of fluid.
If the buoyant force = weight, object remains suspended in fluid.
If the buoyant force < weight, (more dense) the object sinks.

8. Where Is the buoyant force greater?
Freshwater or Saltwater?
Air or water?
Oil or water?
Reading in the Great Salt Lake, Utah

9. Archimedes’ Principle
The weight of the displaced fluid is directly proportional to the volume of the displaced fluid.

10. How can ships made of steel float?
A piece of solid steel sinks in water, but the shape of a ship’s hull allows it to displace a large volume of water.
This creates a large buoyant force, which counteracts the ship’s huge weight.
The effective density of the ship is less than water.

11. Ballast Water - Submarines

12. Applications of Archimedes’ Principle
Submarines A submarine has a large ballast tank, which is used to control its position and depth from the surface of the sea. A submarine submerges by letting water into the ballast tank so that its weight becomes greater than the buoyant force (and vice versa). It floats by reducing water in the ballast tank - thus its weight is less than the buoyant force.

13. Hot Air balloons
A hot air balloon rises and floats due to the buoyant force (when the surrounding air is greater than the balloon’s weight). It descends when the balloon’s weight is more than the buoyant force. It becomes stationary when the weight equals the buoyant force. The weight of the hot-air balloon can be controlled by varying the quantity of hot air in the balloon.

14. Swim Bladders in Fish

15. Where is the buoyant force greater?
Freshwater or saltwater?
Air or water?
Oil or water?

16. Hydrometer
A hydrometer is an instrument to measure the relative density of liquids. It consists of a tube with a bulb at one end. Lead shots are placed in the bulb to weigh it down and enable the hydrometer to float vertically in the liquid. In a liquid of lesser density, a greater volume of liquid must be displaced for the buoyant force to equal to the weight of the hydrometer so it sinks lower. A hydrometer’s small floats higher in a liquid of higher density.

17. Pascal’s Principle

18. any point in an enclosed fluid
Pascal’s Principle
A CHANGE IN PRESSURE at
any point in an enclosed fluid
is transmitted EQUALLY and unchanged in all directions
THROUGHOUT the fluid and
to the walls of the container

19. Hydraulics When a small force or load is placed
on the small piston (F1), it acts
through the liquid to the large piston
to produce a
very large force
on F2 that causes the
load to rise a
shorter distance.

20. Pascal’s Principle Diagram
Left cylinder Right cylinder Cross section = 1 in2 Cross section = 10 in2 Force = 1 pound Force = 10 pound Piston lowered = 10” Piston raised: 1” The 1 pound load on the 1 square
inch area causes an increase in
pressure on the fluid in the system.
As a result, the larger piston lifts up
a 10 pound weight. The larger the
cross-section area of the second
piston, the larger the mechanical
advantage, and the more weight it
can lift.

21. Applying Pascal’s Principle
A hydraulic jack operates on Pascal’s Principle
Can you see why it’s much easier to use a hydraulic jack to lift a car than by hand?

22. Hydraulic Press The hydraulic press is applied in our daily life:
Hydraulic car jack Hydraulic brakes.

23. Hydraulics Quiz
(gbpreble54321)