Measurement of Density Specific Gravity

Jordan University of Science & Technology Civil Engineering Department

Fluid Mechanics & Hydraulics Laboratory CE(354)

Measurement of Density , Specific Gravity And Viscosity of Liquids

Student name

: Sief Mahmoud Zaqi Dqamseh

ID Number

: 20120023097

Section number

: 1

Group number

: B

Date

: 16/10/2015

Introduction

This experiment is about measurement of some important liquids property like Density , specific gravity and viscosity .

The density or more precisely, the volumetric mass density, of a substance is its mass per unit volume.

=

 

The Specific gravity is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the  mass of a substance to the mass of a reference substance for the same given volume.  Apparent  specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance like water .

The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress .

Objectives To determine the density , specific gravity and viscosity of some liquids (i.e. Engine Oil , Glycerol and Castor Oil ) at atmospheric pressure and temperature .

Theory

Specific gravity and density

Liquid denser Distilled Water

than water

FB – W  = 0 Ɣ  w 

 o –

W  = 0

Where :

FB : Buoyant force on the hydrometer ( upward ) W  : Weight of the hydrometer , ( upward )

Ɣ  w  : Specific weight for water .  o:

Submerged volume of hydrometer in water .

∆   : The increase or the decrease of volume of immersion as hydrometer is placed in a liquid other than water .

When the same hydrometer is placed in other liquid the law will be : Ɣ  L (  o ± ∆  ) – W  = 0

Then the equation will be : Ɣ  L (  o ± ∆  ) – Ɣ  w   o = 0 Ɣ Ɣ

=

   ± ∆

=

  ± a∗∆h

=

   ±

a ∗∆h 

=  

………………..(1)

Where SL = Specific gravity of the liquid (S.G )

ρ l = S l ρ w

………………………… (2)

2

(  −  )

9



 = 2

………………………….(3)

Material & Equipment Universal hydrometer 3 hydrometer jars Liquids : engine oil , glycerol and castor oil 3 different diameter spherical steel balls Stop watch   Scale

     

Procedure Firstly measure the diameter of the balls ; but in our experiment we use measured balls . Measure path in the jars by scale and lets use 30 cm and mark it .  

 

Put the hydrometer in the liquid slowly until its stop then read the number on the scale . Take out the hydrometer and clean it to repeat measuring again . Do this steps for all liquid in the jars . 

 

In the first part of this experiment _ Density and Specific Gravity _

In the second part of this experiment _ Viscosity _

Dropping balls in the jars and calculate the time it takes to passing in its path Repeat this step for each liquid and record results .  Finally measure the temperature and air presser .

Raw Data and Results (Calculation). Pressure

= 710 mm hg

Temperature = 27 0 C Liquid Engine oil Glycerol Castor oil

Liquid type Glycerol

Scale measuring " Specific Gravity " 0.885 1.25 0.96

Distance of travel (mm) 300

Ball diameter (mm) 3.9 3.1 2.3

Time (min) 2.69 2.75 6.31

Liquid type Castor oil

Liquid type Engine oil

Distance of travel (mm) 300

Ball diameter (mm) 3.9 3.1 2.3

Time (min)

Distance of travel (mm) 300

Ball diameter (mm) 3.9 3.1 2.3

Time (min)

5.12 7.87 13.57

1.38 1.75 3.15

* Specific gravity for the liquids : Engine oil = 0.885 Glycerol = 1.25 Castor oil = 0.96

For density I will use equation #2 to determine liquid density's ρ l = S l ρ w

………………………… (2)

* Density for the liquids : Engine oil = 0.885 * 997.04 = 882 kg/m 3 Glycerol = 1.25 * 997.04 = 1246 kg/m 3 Castor oil = 0.96 * 997.04 = 957 kg/m 3 at 27 0 C

For viscosity I will use equation #3 2

(  −  )

9



 = 2

………………………….(3)

* Viscosity for liquids AVG : Engine oil = 0.23 pas.sec Glycerol = 0.40 pas.sec Castor oil = 0.93 pas.sec

Sample calculation ρ l = S l ρ w ρ l = 0.885 * 997.04 ρ l = 885 kg/m 3

2

(  −  )

9



 = 2 2

 = ∗( 9

3.9 2 ) 2

∗ 10−6 ∗   9.81 ∗

 = 0.968 pas. sec

(7800 −957.16) 78.59∗10 −3

Discussions In this experiment we can calculate viscosity for three liquids by simple steps Viscosity for liquids AVG : Engine oil = 0.23 pas.sec Glycerol = 0.40 pas.sec Castor oil = 0.93 pas.sec

This property tell us how the movement is easy or how energy we need to lose when this liquid flow .  Also this property reflect very important value its renold number , and from this number we can know if the flow laminar or turbulent . Engine oil and Castor oil less than water this mean just Glycerol will Drown in water Engine oil = 882 kg/m 3 Glycerol = 1246 kg/m 3 Castor oil = 957 kg/m 3 The experiment density of glycerol is 1246 kg/m 3 and theoretically is 1260 kg/m3 so we have some error density maybe it's come from height temperature because of summer. To improve the techniques I think the lab need for new machine because we already have error when measuring the time so we need another way to doing this step .

Conclusions

The result was

Specific gravity for the liquids :

Density for the liquids : Engine oil = 882 kg/m 3 Glycerol = 1246 kg/m 3 Castor oil = 957 kg/m 3

Engine oil = 0.885 Glycerol = 1.25 Castor oil = 0.96

Viscosity for liquids

:

Engine oil = 0.23 pas.sec Glycerol = 0.40 pas.sec Castor oil = 0.93 pas.sec



In high viscosity liquid like Castor oil , ball needs more time to reach to the bottom of liquid jar. From these liquids and our results I think the highest specific gravity has highest density and highest viscosity. As we see the castor oil has highest viscosity but Engine oil have the lower value



This experiment tell us that Glycerol denser than Engine oil and Castor oil



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