Mass is a property used in the study of physics to describe a substance or object. Mass is commonly referred to as weight. Mass and weight are generally proportional, so in everyday terminology, this doesn't cause a problem. In scientific studies and observations, the difference between mass and weight are of greater importance and should be identified and measured separately. The steps below show you how to calculate mass through demonstration, by hand and using Excel.

Calculate mass by demonstration. Place the beaker on the scale. Write down the number shown on the scale, and take the beaker off the scale. Fill the beaker with the liquid. Place the beaker back on the scale. Write down this number as well. Subtract the first number (beaker only) from the second number (beaker and liquid). This result will be the weight, or everyday mass, of the liquid.

Calculate by hand. You can calculate the mass of a liquid if you know the density and the volume. To do so, use the formula: m = p/v (m = mass, p = density and v=volume). To find the mass of 1 cup of water at 40 degrees Celsius, calculate it as: p = the density of water is .9922 at 40 degrees Celsius; v = the volume of 1 cup of water is 250 ml; m = .9922/250; m = 0.0039688.

Use Microsoft Excel. You can calculate the mass of a liquid if you know the density and the volume. To do so, use the following formula: m = B2/C2 Cell A1 = B2/C2 (m = mass = Cell A1, p = density = Cell B1, v = volume = Cell C1)