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Density is a useful property to know for other reasons besides whether or not something will float in water. It is also taken into consideration for many car repair services.

We know how important it is to calculate accurately. That's why we have this density formula calculator available to you at any time. Simply add two variables from mass, volume, or density and it will solve for the third.

To learn everything you need to know about density, its function, and its purpose in our world, continue reading below.


What is density, and why does it matter?

Everything in the universe has a density - except for empty space itself. A better way of putting it is: everything that has mass has a density.


Density is defined as the relationship between the mass of an object and its volume. Basically, density is the property of a material that relates how much of its atoms and molecules can fit into a certain amount of space.

It might be easy to think of density as the weight of a material, but this is not exactly correct. It's true that a bowling ball has a higher density than a feather, but it is not because of the two materials' weights.


Density is as important as every other facet of the laws of physics. Physics determine how every physical thing in this universe will react, and density is vital for this reason.

What is the formula for density?

The formula of density is a pretty simple one. It can be calculated like this:

d = M / V

The "d" stands for density, the "M" is for mass, and the "V" is for volume.

In other words, density is calculated by taking a material's mass divided by its volume (the space it takes up). Each material has a density that never changes no matter its size, which means that density is considered an intrinsic property.

Measuring Density

Mass is usually measured in the unit of a gram, and volume (at least when it comes to density) is commonly measured in the unit of a cubic centimeter.

So, density is most often expressed in units of grams per cubic centimeter.

Solving For Mass or Volume

With this simple density equation, it is actually easy to discover a material's mass or volume. If you have any two properties in this formula, simply rearrange the equation to calculate the missing property.

Here's how to do that:

Mass = Volume * Density

Volume = Mass / Density

What is the standard unit of density?

Sometimes different units of measures are used, but for the most part, professionals tend to stick with grams per cubic centimeter.

An important measurement of this density is water, which is shown to always be exactly 1.0 gram per cubic centimeter.

Other Examples

Other common densities that might interest you, are:

  • Feathers - 0.0025 g/cm3
  • Ice - 0.92 g/cm3
  • Steel - 7.8 g/cm3
  • Silver - 10.5 g/cm3
  • Gold - 19.3 g/cm3

Notice that silver indeed does have a lower density than gold! (more on this later)

Specific gravity and buoyancy

The fact that water has a common density of 1.0 is a particularly useful property. Pretty much all other materials are compared to water at one point or another.

The property of other materials, when compared to water, is called specific gravity. The specific gravity is noted for many reasons, particularly when someone wants to note the ability of the material to float or sink in water.

In fact, buoyancy is perhaps the most useful property that is determined by the formula for density.

Specific gravity is sometimes called relative density. If the density of a material is greater than 1.0, it will sink in water. If it is less than 1.0, it will float!

When was density discovered?

Density was first discovered in 250 B.C.E. by Archimedes, a rather famous Greek mathematician of the time. In fact, he discovered as a by-product for a certain task he was charged with.

As the historical story goes, Archimedes was tasked with determining whether or not the King of Syracuse's craftsman was lying to him about the purity of the golden crown presented to the king.

The king had a suspicion that the crown he had gotten was actually a fraud, mostly made of silver instead of gold.

Later, Archimedes drew himself a bath. When he got in the tub, he noticed that some of the water spilled out, which got him thinking.

He recognized that his body mass displaced some of the water, and he then had the first thoughts about what a material's density could mean. He decided to test the crown in a similar manner.

He placed the crown in question and a truly pure gold crown in a tub of water. He knew that silver had a lower density than gold and would, therefore, displace more water since the mass of the two crowns were the same.

He found that the crown in question was, in fact, a fraud! It displaced more water than the pure gold one.

You might have heard the famous line, "Eureka!", which is associated with figuring something out. We have Archimedes to thank for that, who shouted the Greek phrase when he discovered the lies of the king's craftsman.

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