How Do You Make A Simple Hydrometer?
A hydrometer is a type of instrument that measures the density of liquids. Making a simple hydrometer to measure the density of several types of liquids is a good science project for elementary or middle school students. Building a hydrometer takes only a few common materials that you probably have in your home. Once you have your hydrometer, you can use it over and over again for various projects. It will be easy for anyone to use, because if you know how to read a thermometer, you can read a hydrometer. Roll a small piece of clay into a ball one centimeter around. Plug one end of the straw with the clay ball. Fill a graduated cylinder with water to the 100 ml line. Place the straw into the graduated cylinder, with the clay ball at the bottom and one inch of the straw sticking out of the water. Add or remove some of the clay ball to make the top of the straw stick out one inch. Use a ruler to help you. Mark the straw with a permanent marker where the top of the water hits the straw. T
