Free Surface Of A Static Liquid

OBJECTIVE

To show that the surface of a static liquid is horizontal   

APPARATUS AND DIAGRAM

v Tank 1 and tank 2

v Tube a,b and c

v Hand Pump

v Valve 1,2,3,4,5 and 6

v Horizontal lines

PROCEDURE

1.    Make sure valves V₂ ,V₄ and V₅ are closed

2.    Open valves V_1, V₃  and V₆

3.    Using hand pump transfer water from tank 2 to tank 1 until the level of the water coincides with the  first horizontal line on the tank

4.    Note the level in each of the three tubes “a” , “b” ad “c” is the same and in line with the first horizontal line on the tank

5.    Repeat for the second, third and fourth horizontal lines noting that the level of the water is always horizontal, irrespective of the tube size or shape

6.    Drain the water from tank 1 by opening the forth valve and re-establish the level at the first  horizontal  line

7.    Close the valve V₄ and ensure that valve V₁ is open. Close valve V₆ at the top of tube “a”(tube “a”, therefore, no longer has a free surface)

8.    Using the hand pump, transfer water from tank 2 to tank 1. Raise the level in the tank 1 to the second, third and the fourth horizontal line. Note that the level in “a” remains depressed  whilst, “b” and ”c” follow the level in the tank as (3) above

CONCLUSION

From the experiment, I observed that when the liquid in different pipe’s sizes and shapes were exposed to the same pressure conditions, the level of liquid remain constant but when the pressure at the top of the tubes is changed  the level of the liquid inside it reduce

   From the above observation it was conclude that;  matter the diameter of the container used and regardless of it cross-section  and size, the level of the liquid will remain the same in all the containers provided they are fed from same source

ERRORS

Personal error: This is due to the top off the valves not being tightly closed

Instrumental error: The use of bowl instead of hand pump in transferring the water from tank1 to tank2 

Precaution

·     Make sure the valves which are meant to be closed are closed tightly

·     The transfer of water from the tanks must be done carefully

THEORY

Fluid statics is concerned with fluids at rest. A fluid is said to be at rest in the absence of shear stress and hence all forces due to static pressure must act at right angles to be containing surface. With a static fluid the only physical quantity concerned. Accordingly, the surface of the fluid will always be horizontal such the pressure applied at a point will be the same at all point in the horizontal plane.

OBSERVATION

It was observed that when the liquid was exposed to the same pressure conditions the level of the liquid remains the same and when the pressure at the top is changed the liquid in the tubes reduced

POST LAB ASSIGNMENT

1.  State two applications of static pressure experiment.

2.  Explain what will happen if the experiment was carried out at higher altitude .

3.  Differentiate between the static pressure experiment and the capillary experiment..

ANSWERS

1(i) It in used designing and operating aircraft.                      

(ii) It used in fluid dynamics.

2 The liquid in the tubes will remain the same regardless of the altitude in which the experiment was carried out.

      3(i)) Static pressure experiment is showing the effect of pressure on a liquid along the horizontal axis while the capillary experiment is about the effect of diameter of the capillary tube on the rise of liquid in it.

        (ii) The static pressure experiment is to show that the free surface of a static liquid is horizontal while capillary experiment is to show capillary elevation produced by various sizes of tubes.

A report compiled by ADEEYO TOHEEB OLASUNKANMI who is an undergraduate student of CHEMICAL ENGINEERING