In order to calculate density, you have to know two measurements: the mass and the volume of the object.

To determine the mass of an object, you use a triple beam or electronic balance. Mass is expressed in grams.

If the object is a regular shaped object, such as a cube, you can determine the volume mathematically using the formula for volume. The formula for volume of a rectangular prism or cube is

Volume = B × h (B = area of the base), or Volume = length × width × height

The unit for volume is always expressed as units cubed. For example, cm³.

Let’s practice. Determine the volume of the objects below.

What if the object is irregular in shape, such the crown Academies tested, or a rock? How do you determine the volume? You cannot determine the volume of an irregular shaped object using a mathematical formula. To determine the volume of an irregular shaped object, we must measure the fluid displaced using a graduated cylinder and water.

Let’s practice measuring displacement.

Since the density formula is mass ÷ volume, the unit for density is grams per cubic centimeter, or g/cm³.

If we have a table of known densities, we can identify the type of material that makes up the sample. Use the table below to determine the material that makes up the sample.

What type of material was the sample?

Interactive popup. Assistance may be required.

Check Your Answer

brick