Does Limestone Float? (You Might Be Surprised)

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While there are some types of stone that can float for a period of time, limestone is not one of them.

This incredibly important material, which has been used by humans for thousands of years.

This is largely due to the density of limestone, which makes it solid and durable.

However, these are the same properties that keep it from being able to float in water. 

Does Limestone Float? (EXPLAINED)

What is Limestone?

Limestone is a type of sedimentary rock that is made of calcite and aragonite.

It is formed by these minerals precipitating from water with calcium in it.

This means that limestone is primarily found in shallow waters and near coastlines.

In other cases, limestone can be found in regions that were at one point underwater, but due to the shifting of Earth’s tectonic plates is now no longer covered by ocean water.

It should also be noted that because limestone is soluble in rainwater, it can be found around all of Earth. 

Historically, limestone is used for a wide variety of purposes.

Notably, the pyramids at Giza are made of limestone, as it has long since been used as an effective building material.

It has also proven to be good for carving statues due to the various properties of the stone itself.

Today, limestone is still used in modern construction.

However, it is more often used as part of a cement mixture or when something needs to be built with stones.

This means that it is vital to everything from roads, to sidewalks, to the construction of homes and as a decorative piece.

All of these uses make limestone incredibly valuable. 

Part of what makes limestone such an effective building material is its weight and density.

Because of this, and how limestone forms, it can often be found underwater where it has become a key structure in underwater ecosystems. 

What Causes An Object to Float?

Whether or not something floats is due to its density as an object.

This is because everything is made up of molecules.

In some objects, these molecules are tightly packed together, while others are more loosely packed.

This is the difference in density from one object to another.

It’s also what causes something to sink or float.

An object that you might think of as being buoyant is really just a non-dense item.

Something you might think of as sinking due to its weight is sinking because of its density. 

Interestingly, while we may think of density as being associated with weight, this is not the only factor in whether something sinks or not.

Think of a ship, which is certainly heavier than a rock, yet it will float.

This is because of buoyancy, which is also referred to as the Archimedes’ Principle.

Simply, any object in water is subject to an upward push of water, or buoyant force, which is equal to the weight of the displaced water by the object.

A ship then floats because it displaces more water, creating a more buoyant force.

Therefore, a buoyant force being equal to an object’s weight will cause that object to float.

However, if the buoyant force is less, then the object sinks. 

Archimedes famously made this discovery about water and how objects act in it while taking a bath, where he observed his own ability to sink into the water and saw the level of the water move as it was displaced. 

Why Limestone Does Not Float

For anyone wondering, “Does limestone float?” it comes down to a couple of simple reasons.

It is denser than fresh or ocean water.

Furthermore, when a piece of limestone enters water, it has more force behind it than the buoyancy effect is pushing upwards at the piece of limestone.

This will prevent it from floating towards the top of the water, causing it to sink. 

Interestingly, while limestone doesn’t float, there are some rocks that are known to float in water.

The University of California has found that pumice stones, which are lightweight and porous, can float for extended periods of time.

Different bodies of water also have different levels of buoyancy themselves.

The Dead Sea and the Great Salt Lake are two salt lakes that are known to be easier to float on than other bodies of water.

The Dead Sea, for instance, has a massive salt concentration, which makes it much more dense than other bodies of water.

This counters the density of whatever is going into the water, and could hypothetically make it easier for a rock or other dense object to float. 

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