Calculating Density

Density is an objects mass divided by its volume. So if you know that an objects mass and its volume, you can calculate that objects density.

Calculating Density

Below are a few examples of calculating density:

Problem #1. Find the density of the cube.

So, from the the triple beam balance, we see that the cube has a mass of 105.6g. The volume of the cube is the length x width x height (1 x 1 x 1), which is 1 cm3. Now you can use the density formula,

Density = Mass/Volume

= 105.6 g / 1 cm3

= 105.6 g/cm3

So the density of the cube is 105.6 g/cm3

Problem #2. Find the density of the rock.

The mass of the rock is 190.3g. Now you must determine the volume, but due to its shape you must use the water displacement method.

The initial volume of the graduated cylinder is 20 mL. The final volume of the graduated cylinder (with the rock added) is 23 mL. Thus, to find the volume of the rock, you must subtract the initial volume from the final volume.

23 mL - 20 mL = 3 mL

Thus, the volume of the rock is 3 mL.

Now, to calculate density, use the formula:

Density = Mass/Volume

= 190.3g / 3 mL

= 63.4 g/mL

So the density of the rock is 63.4 g/mL