How do you use hydrometer to find the density of dock water?

To find the density of dock water using a hydrometer, first ensure the hydrometer is clean and calibrated. Gently lower the hydrometer into the dock water until it floats freely, making sure not to touch the sides of the container. Once it stabilizes, read the measurement at the water's surface level on the scale of the hydrometer, which indicates the specific gravity of the water. To convert this value to density, multiply the specific gravity by the density of pure water (approximately 1 g/cm³ at 4°C).