1. Basic Hydraulics Density, Specific Gravity
Math for Water Technology
MTH 082 and Water Works Operation WQT 111
Lecture 4
Hydraulics Chapter 1
(pgs )

2. Objectives/Discuss Density Specific Gravity Bulk Density
Density of a Fluid

3. What is Density? Density= Mass/Volume ρ = m / V
The weight per unit of volume.
Density= Mass/Volume
ρ = m / V
ρ is the object's density (measured in kilograms per cubic meter)
m is the object's total mass (measured in kilograms)
V is the object's total volume (measured in cubic meter)
Units:
lb/ft3 (sand, activated carbon, lime, soda ash, air, chlorine gas, methane, carbon dioxide)
lb/gal (water, liquid aluminum, liquid chlorine)

4. A substance weighs 378 g and occupies a space of 48 cm3
A substance weighs 378 g and occupies a space of 48 cm3. What is its density in grams per cubic centimeter?
g/cm3
7.9 g/cm3
18,144 g/cm3
378 g/cm3

5. What is the density in pounds per gallon of a 1
What is the density in pounds per gallon of a 1.00 L solution that weighs 2.29 lb?
2.29 lb/gal
8.67 lb/gal
0.12 lb/gal
0.43 lb/gal

6. The density of an unknown substance is 2. 14 g/cm3
The density of an unknown substance is 2.14 g/cm3. How much space would this substance occupy in cubic centimeters if it weighed 3.3 lb?
We know that 2.14 g of substance occupies 1 cm3 by knowing its density. To get the space 1,498.2 g occupies, divide by the density.
700 cm3
0.015 cm3
0.65 cm3
1500 cm3

7. The density of a substance changes slightly as the temperature of the substance changes.
(T) Substances increase in size (expand volume) as they become warmer. Density is lower in warm substance but greater in cold substances, cool=condense
True
False

8. What is Density? 2 ft3 or 0.1 lb 1 ft3 or 0.1 lb Cold Higher Density
Warm Lower Density

9. In water supply operations, the density of water varies slightly with temperature.
(T) However, at the constant temperatures in water supply operations the change is negligible.
True
False

10. Water is the most dense at 39
Water is the most dense at 39.2 oF and becomes less dense when the temperature rises or falls.
(T) water is an unusual substance that acts differently from everything else..
True
False

11. What is Bulk Density?
Bulk density is the weight of a cubic foot of material as it would be shipped from the supplier to the treatment plant. It is the mass of many particles of the material divided by the volume they occupy. The volume includes the space between particles as well as the space inside the pores of individual particles.
Bulk density is a measure of the weight of the substance per unit volume (g/cc). Includes volume of the air, amount of air

12. This physical property is what prevents salt and freshwater from mixing in an aquifer or underground basin.
Specific gravity is related to density. Since the seawater is more dense, it doesn't mix freely with the freshwater. It's similar to what happens with water and oil.
Specific gravity
Temperature pH
Van der waals forces

13. What is specific gravity of a liquid?
Specific Gravity- is the density of a substance relative to the standard density of water which is 62.4 lb/ft3 or 8.34 lb/gal. It’s a ratio of a substances density to that of water.
SG= density of substance
62.4 lb/ft3 or 8.34 lb/gal
SG is used as a way to compare to separate materials.
Its done at a fixed temperature and pressure for a given substance.

14. Example 1. The density of granite rock is 162 lb/ft3 and the density of water is 62.4 lb/ft3. What is the specific gravity of granite?
162 lb/ft3
62.4 lb/ft3
162 lb/ft3 =
62.4 lb/ft3

15. Example 2. The density of SAE motor oil is 56 lb/ft3 and the density of water is 62.4 lb/ft3. What is the specific gravity of the motor oil?
56 lb/ft3
62.4 lb/ft3
56 lb/ft3 = ; its 9/10 as dense as water!
62.4 lb/ft THAT’S WHY OIL FLOATS ON H2O

16. Example 3. The density of aluminum is 168 lb/ft3 and the density of water is 62.4 lb/ft3. What is the specific gravity of the aluminum?
168 lb/ft3
62.4 lb/ft3
168 lb/ft3 =
62.4 lb/ft3

17. Example 4. The specific gravity of SAE motor oil is 0
Example 4. The specific gravity of SAE motor oil is 0.92 and the density of water is 62.4 lb/ft3. What is the density of the motor oil?
0.92= ??? lb/ft3
62.4 lb/ft3
(X) lb/ft3 = ; (X lb/ft3) = 62.4 lb/ft3 (0.92)
62.4 lb/ft3 (X) = lb/ft3

18. Pumped Conversion Rate
Example 5. Suppose you wish to pump a certain liquid at the rate of 25 gpm. How many lb per day will be pumping if the liquid weighs 74.9 lb/ft3?
74.9 lb/ft3
74.9 lb/ft3 =
62.4 lb/ft3
H20 Specific Gravity
8.34 lb/gal (1.20) =10.01 lb/gal
Pumped Conversion Rate
(25 gpm) (10.01 lb/gal) (1,440 min/day) = 360,360 lb/d pumped

19. A fluid with a specific gravity of 1.05 weighs _____ lb/gal.
Given : Sg= Need lb/gal
Conversions 8.34 lb/1gal
8.34 lb (1.05) = 8.75 lb/gal
gal
8.4
8.8
7.2
8.5

20. If water weighs 8.34 lbs/gal, how much will 7.5 gal weigh?
Given : 8.43 lbs/gal and 7.5 gal
Conversions 8.34 lb/1gal
8.34 lb (7.5 gallons) = 63 lbs
gal
50.8 lbs
62.6 lbs
75.5 lbs
77.3 lbs

21. 1240 gal 0.93 SG H20 Specific Gravity 8.34 lb/gal (0.93) =7.76 lb/gal
Example 6. There are 1,240 gal of a certain liquid in a tank. If the specific gravity of the liquid is 0.93, how many pounds of liquid are in the tank?
1240 gal
0.93 SG
SG=0.93
H20 Specific Gravity
8.34 lb/gal (0.93) =7.76 lb/gal
Conversion Rate
(7.761 lb/gal) (1240 gal) = 9,622 lb

22. A liquid has a specific gravity of 1
A liquid has a specific gravity of How much would 300 gallons of this liquid weigh?
Given : Sg= 1.16 and 300 gallons?? Need weight
Conversions 8.34 lb/1gal
8.34 lb (300 gallons) = 2502 lbs
gal
2502 lbs (1.16) = 2902 lbs
2902 pounds
348 pounds
2502 pounds
2156 pounds

23. What is specific gravity of a gas?
Specific Gravity- is the density of a gas substance relative to the standard density of air which is lb/ft3 at 20oC and a pressure of 14.7 psia (pounds per square inch absolute)

24. Cl2 Specific Gravity = 0.187 lb/ft3 / 0.075 lb/ft3 = 2.49
Example 7. The density of chlorine gas is lb/ft3. What is the specific gravity of this gas?
Specific gravity of Cl2 gas= (density of Cl2 gas)
density of air
Cl2 Specific Gravity = lb/ft3 / lb/ft3
= 2.49
Chlorine gas is about 2.5 times as dense as air

25. Today’s objective: to discuss the concept of density and specific gravity has been met.
Strongly Agree
Agree
Neutral
Disagree
Strongly Disagree