The Specific Gravity of Two Liquids Using a Hydrometer - Lab Report Example

The value of Gs is a numerical value with no units and does not depend on which system of units is used since it is a ratio. The specific gravity of a liquid is a significant parameter in industrial processes, and it is a factor in most equations that involve weight-volume relationships. For instance, if during an industrial process sugar syrup or salt solution is needed, it can be easily determined if the solution has the correct concentration by measuring its specific gravity at a particular temperature.

The specific gravity for liquids can be written as: Gs = density of the density (g/cm3)/ density of water (g/cm3) Theory: Specific gravity is the ratio of the density of a fluid to the density of water at a constant temperature. Specific gravity can be calculated directly from the measured density of a liquid divided by the density of distilled water. A suitable alternative method is to use a hydrometer. This is a specially calibrated instrument made of a hollow glass float designed to float vertically in liquids of different densities.

The depth to which the hydrometer sinks in the liquid represents the density of the liquid. The instrument has a calibrated scale on its stem which is used to read specific gravity. The diameter of the stem determines its sensitivity of the stem. An exceptionally sensitive hydrometer has a thin stem and a large bulb (Frey, 44). Experimental Procedure The glass cylinder was placed on a flat-level surface and filled with sample liquid to allow air to rise to the top. The hydrometer was gently lowered into the flask with the bulb end facing down without it coming into contact with the sides of the fluid.

The measurements of specific gravity measurements for each of the two fluid samples were taken and recorded with the hydrometer floating freely in the fluid. The hydrometer was removed and the procedure was repeated nine times for each of the two liquids. The values of specific gravities were compared. Description of apparatus: Hydrometer, glass cylinders Data: Measurements Sample S Sample E 1 1110 900 2 1120 890 3 1123 870 4 1124 860 5 1110 890 6 1100 900 7 1110 890 8 1120 880 9 1000 900 10 1110 890 Average 1102.7 887 Results/calculations: Average specific gravity for sample S = (1110 +1120+ 1123+ 1124 +1110 +1100 +1110 +1120+ 1000+ 1110) /10 =1102.7 Average specific gravity for sample = (900 +890+ 870+ 860+ 890+ 900 +890 +880+900 +890) /10 =887

Conclusion/discussion: The specific gravity of a liquid is the same everywhere since it is the ratio of the density of the liquid to the density of water at 40C whereas density is mass per unit volume. Thus, the denser the liquids, the higher the specific gravity obtained. This explains why it is easier to swim in seawater than in swimming pools because the density of seawater is higher than that of swimming pool water. The existence of salt increases the density of seawater. The specific gravity of fluids was successfully obtained using the hydrometer; thus the goal of the experiment was achieved.