What Is the Specific Gravity of Water?

Series Summary

Science describes the method of observation, analysis and discovery to help explain how things work and why things happen in the physical world. Often, the scientific method is used as a reproducible way to analyze experiments, and it includes formulating a question, researching the topic, constructing a hypothesis, experimenting, analyzing the data and drawing a conclusion. This method is taught to children at an early age to aid in problem solving and to get them interested in the world around them. In this free video series on science, a math and science teach explains how to determine the specific gravity of water.

Video Transcript

"Hi, I'm Steve Jones, and I'm going to explain what the specific gravity of water is. It's quite a strange question, because specific gravity relates specifically to water anyway, but I'll explain that in a moment. First of all, let's take a one centimeter cube., one centimeter by one centimeter, by one centimeter, so it's volume is one centimeter cubed, so the volume is one centimeter cubed. Now, the mass of this cube, will be actually one gram, if it is water. If this is a cube of water, then its mass is one gram, so because we have this quantity density, its density which is important in this case. Density is how heavy something is, so density is mass divided by volume. The mass is one, the volume is one, and that gives us a density of one gram per centimeter cubed. That is the density. Now, specific gravity as such, is slightly different from density, and much more useful, because specific gravity tells us how much heavier some material is, compared to water, so it is not how many grams per centimeter cubed, it is a number. It is a ratio, so it is the mass of a cube, of whatever substance you're interested in, divided by the mass of water, so the specific gravity of water, is the mass of one centimeter cubed of water, divided by the mass of one centimeter cubed of water, and something divides by itself. The answer is one. Of course, water is the standard, water has a specific gravity of one, so that is what the specific gravity of water is."