To calculate the Corrected Gravity (CG):
\[ CG = MG \times CF \]
Where:
To calculate the Correction Factor (CF):
\[ CF = \left(1.00130346 - 0.000134722124 \times ST + 0.00000204052596 \times ST^2 - 0.00000000232820948 \times ST^3\right) - \\ \left(1.00130346 - 0.000134722124 \times CT + 0.00000204052596 \times CT^2 - 0.00000000232820948 \times CT^3\right) \]
Where:
Hydrometer correction is the process of adjusting the specific gravity reading of a liquid to account for the temperature difference between the liquid and the calibration temperature of the hydrometer. Hydrometers are typically calibrated at a specific temperature, and when the temperature of the liquid being measured is different, the density and thus the specific gravity reading can be affected. The correction ensures that readings are accurate and consistent, regardless of the temperature of the sample.
Let's assume the following values:
Using the formulas:
\[ CF = \left(1.00130346 - 0.000134722124 \times 25 + 0.00000204052596 \times 25^2 - 0.00000000232820948 \times 25^3\right) - \\ \left(1.00130346 - 0.000134722124 \times 20 + 0.00000204052596 \times 20^2 - 0.00000000232820948 \times 20^3\right) \]
\[ CF = (1.00130346 - 0.00336778 + 0.00127533 - 0.0000364) - (1.00130346 - 0.00269444 + 0.00081621 - 0.00001863) = 0.0004652 \]
\[ CG = 1.050 \times 0.0004652 = 1.00049076 \]
The Corrected Gravity is 1.000491 SG.
Let's assume the following values:
Using the formulas:
\[ CF = \left(1.00130346 - 0.000134722124 \times 30 + 0.00000204052596 \times 30^2 - 0.00000000232820948 \times 30^3\right) - \\ \left(1.00130346 - 0.000134722124 \times 20 + 0.00000204052596 \times 20^2 - 0.00000000232820948 \times 20^3\right) \]
\[ CF = (1.00130346 - 0.00404166 + 0.00183797 - 0.0000628) - (1.00130346 - 0.00269444 + 0.00081621 - 0.00001863) = 0.0006408 \]
\[ CG = 1.080 \times 0.0006408 = 1.001091 \]
The Corrected Gravity is 1.001091 SG.
