1. What is Specific Gravity of Water?

Definition: The specific gravity of water is defined as 1.0, serving as the reference point for all other materials.

Density: Water has a density of 62.4 pounds per cubic foot (lb/ft³) at standard conditions (4°C or 39.2°F).

2. Why is 62.4 lb/ft³ Important?

This value serves as the basis for calculating specific gravity of other materials:

Applications:

• Determining buoyancy of objects
• Calculating material weights in fluid mechanics
• Mixing ratios in concrete and other construction materials

3. Standard Conditions

Temperature: The density of 62.4 lb/ft³ is measured at 4°C (39.2°F), water's temperature of maximum density.

Pressure: At standard atmospheric pressure (1 atm or 14.696 psi).

4. Frequently Asked Questions (FAQ)

Q1: Does water density change with temperature?
A: Yes, water density decreases as temperature moves away from 4°C in either direction.

Q2: Why is specific gravity dimensionless?
A: Because it's a ratio of two densities, the units cancel out.

Q3: How is this used in concrete calculations?
A: Specific gravity helps determine absolute volume of materials in concrete mix designs.

Q4: What's the metric equivalent?
A: 1000 kg/m³ or 1 g/cm³ at 4°C.

Q5: Does salinity affect water density?
A: Yes, seawater (3.5% salinity) has density of about 64.0 lb/ft³.