TABLE OF CONTENT
CONTENTS PAGE
Title Page – – – – – – – – i
Certification – – – – – – – ii
Dedication – – – – – – – – iii
Acknowledgements – – – – – – iv
Table of Contents – – – – – – – v
CHAPTER ONE
- INTRODUCTION – – – – – 1
CHAPTER TWO
- Overview of relative density – – – – 3
- Factors affecting relative density – – – 3
- Density of Common Substance – – – – 4
- Hydrostatic weighing – – – – – 5
- Hydrometer – – – – – – 7
- Pycometer – – – – – – – 12
- Measurement of Relative Density – – – 17
CHAPTER THREE
- Application of Relative Density – – – 19
CHAPTER FOUR
- SUMMARY, CONCLUSION AND REFERENCES – 20
- Summary and Conclusion – – – – 20
References
CHAPTER ONE
1.0 INTRODUCTION
Relative density or specific gravity is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest (at 4 °C or 39.2 °F); for gases, the reference is air at room temperature (20 °C or 68 °F). The term “relative density” is often preferred in scientific usage (Dana and Edward, 2002; Schjetz et al., 1999).
If a substance’s relative density is less than 1 then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of the two substances have the same mass. If the reference material is water, then a substance with a relative density (or specific gravity) less than 1 will float in water (Goodluck, 2002).
For example, an ice cube, with a relative density of about 0.91, will float. A substance with a relative density greater than 1 will sink. Temperature and pressure must be specified for both the sample and the reference. Pressure is nearly always 1 atm (101.325 kPa). Where it is not, it is more usual to specify the density directly. Temperatures for both sample and reference vary from industry to industry. In British brewing practice, the specific gravity, as specified above, is multiplied by 1000 (Hough et al., 2001).Specific gravity is commonly used in industry as a simple means of obtaining information about the concentration of solutions of various materials such as brines, sugar solutions (syrups, juices, honeys, brewers wort, must, etc.) and acids.
