How to Calculate Density
What Is Density?
First things first: What is density? When we talk about the density of a certain material, we’re talking about how compactly the matter it’s made of is packed. Put more precisely and more
How to Calculate Density
What Is Density?
First things first: What is density? When we talk about the density of a certain material, we’re talking about how compactly the matter it’s made of is packed. Put more precisely and more mathematically, the density of a material is the amount of mass contained in a given volume—say the number of grams per cubic centimeter or kilograms per cubic meter.
Density gives us a consistent way to calculate and compare the compactness of different materials.
The mass of something is really just a measure of how much stuff that something contains. By “stuff” I mean the number of protons and neutrons contained in its atoms (since that’s where almost all the mass of an atom is). So the density of a material is a measure of how many protons and neutrons it contains in a given volume. High density materials like metals have lots of “stuff” per unit volume, while low density materials like the air we breathe have a lot less “stuff” in that same volume.
The important thing to know is that density is useful because it gives us a consistent way to calculate and compare the compactness of different materials.
Some Good Densities to Know
As a quick aside, it’s useful in life to know a few numbers by heart. One of those numbers that’s good to know is the density of water. Why? Mainly because it’s a convenient baseline material that we’re all familiar with, and as such it’s convenient to use as a comparison for densities of other materials.
Water has a density of 1 gram per cubic centimeter. This means that if you were holding a 1 cubic centimeter cube of water in your hand (that’s about the size of a sugar cube), it’d weigh 1 gram. This, as an added bonus, now gives you a good way to think about how much 1 gram weighs.
Just for comparison:
- The density of air at sea level is about 0.001 grams per cubic centimeter or about 1,000 times less dense than water
- The density of normal everyday rock is a little less than 3 grams per cubic centimeter or about 3 times the density of water
- The density of iron is just shy of 8 grams per cubic c