Gold will sink when placed in liquid mercury.
Despite Mercury being extremely dense, gold is even denser, and for this reason, gold will not float on the surface of mercury as most other objects do.
Let’s look at why gold sinks when you submerge it in mercury and discover some of the other properties and uses we have for these two metals.
Will Gold Sink or Float In Liquid Mercury? (EXPLAINED)
Understanding Buoyancy
A liquid exerts an upward force on any object that is placed in it.
This force is known as buoyancy.
According to the Archimedes principle, the buoyancy force is equal to the weight of the fluid which is displaced.
It is important to note that it is not the weight of the object that determines whether it floats or not.
Rather, it is the density of the object in comparison to the density of the fluid which will determine the object’s ability to float.
The denser an object is, the heavier it becomes.
As buoyancy is determined by the weight of the liquid that is displaced, a very dense object will displace a far greater amount of the liquid required to support it before the object’s weight is balanced by the upward buoyancy force.
It will therefore pass through the liquid as there is insufficient buoyancy to support its weight.
You can visualize this by considering that both wooden and steel boats float.
However, when you place a block of wood and a block of steel of the same dimension in a bucket of water, the wood floats but the steel sinks.
Now take that same piece of metal, beat it out into a very thin sheet, and create a ship’s hull out of it.
The steel will now float in water because the amount of water that is displaced by the hull weighs more than the weight of the steel.
It is just that the steel is spread out over a much greater area displacing a greater quantity of water than when it was just a very dense block.
Mercury – Liquid Metal
Mercury is a liquid metal.
Its density is greater than that of lead.
What this means is that heavier objects with a lesser density will float when placed in a Mercury bath.
Only objects with a greater density will sink and gold is one of them.
To demonstrate this, you can place a lead weight into a Mercury bath and watch it float.
However, if you now place a gold nugget into a Mercury bath, it will sink.
The large lead weight will float whilst the small gold nugget will sink.
This proves that it all comes down to density, not weight!
Why Does Gold Sink In Mercury?
Gold will sink when placed in a Mercury bath due to its higher density.
The density of Mercury is 13.546. the density of gold is 19.3.
The weight of gold compared to the weight of Mercury does not play a part in this process.
We need to know this to find out if an item is in fact pure gold.
If in doubt, testing a piece of gold by placing it in a mercury bath will definitively provide an accurate answer.
The Physical Characteristics of Mercury
Mercury has a silvery-white color and is a shiny metal with a mirror-like luster.
It is odorless and has a slightly metallic taste.
It is also highly toxic.
It will remain in a liquid state at room temperature and is insoluble in water.
You may have heard it referred to as quicksilver due to these qualities.
Mercury has high surface tension.
This means that the surface of the liquid is highly resistant to any external forces.
This is due to the cohesive nature of Mercury’s molecules.
If it is spilled, it will break up into little beads, which can easily disperse and become lodged in cracks in the floor or other surfaces.
Mercury has a high density of 13.546.
A high density means that mercury particles are tightly packed together with little to no space between them.
Mercury dissolves when it comes into contact with hot sulfuric acid or cold nitric acid.
It begins oxidizing when heated to form Mercury oxide.
At room temperature, Mercury will not oxidize. However, Mercury is corrosive when it comes in contact with aluminum.
Physical Characteristics of Gold
Gold is a yellow metal that is soft and malleable.
So soft, in fact, that it can be scratched by an item as small as a needle, and can be beaten into extremely thin sheets.
One ounce of gold can be beaten into a sheet measuring 300 sq feet or stretched into a wire 50 miles long.
In its purest form, it is easily misshapen, so it needs to be protected and shielded from harm.
It is the 7th densest metal on the periodic table.
Gold is a great conductor of heat and electricity and is not affected by exposure to oxygen.
This makes it ideal for use in conditions where oxidation or rust is a problem.
Gold is inert and a good reflector of infrared radiation as it has the highest reflectivity of any material in the infrared spectrum.
Gold is usually alloyed, being mixed with other harder metals, to increase its strength and utility.
Pure gold is measured in Troy weight and when gold is alloyed with other metals it is measured in Karats, to express the amount present.
Industrial and Commercial Uses of Mercury
Mercury is used extensively in industry for batteries, electronics, and mechanical appliances.
Fridges, washing machines, vacuum cleaners, computers, and phones all contain Mercury.
These are usually due to a drop or two being used in switches.
Lighting units and lamps often contain Mercury.
Many appliance manufacturers are trying to move away from using Mercury due to its toxicity and the impact it has on the environment when appliances are disposed of and not recycled.
Mercury has been used in products to fill cracks in walls before covering them with plaster or drywalling.
It’s used as a lubricant in turbines, and metallic Mercury amalgams are used to fumigate and protect grain in closed containers.
Mercury can also be found in some tattoo ink.
An amalgam, being Mercury combined with another metal, such as silver or tin, is used in dentistry to fill cavities in teeth.
Substantial amounts are used in the production of both chlorine and caustic soda.
Though Mercury is not flammable, it does give off toxic fumes in a fire.
Physical Characteristics of Gold
In the periodic table, gold is classified as a transition metal.
It is highly reflective, doesn’t absorb light or heat (both reflect off its surface), yet electric charges pass through it easily. It has no magnetic effect.
Gold cannot be corroded other than by using aqua regia, a mixture of nitric and sulfuric acid. It is an extremely precious metal.
For centuries, alchemists searched for the secret to turning lead into gold, with no success.
Gold Alloys
Gold can be combined with copper, silver, and platinum, amongst other metals, to produce alloys that have a higher strength or hardness than pure gold.
Pure gold is marked with a stamp indicating that it is 24 carats.
Once additional metals are added, the gold alloy produced is rated on a scale of fewer than 24 carats.
For instance, a mixture of 18 parts of gold with 6 parts of another metal is rated at 18 carats.
Gold is one of only a few elements that is found in its native state.
It can be found either as pure nuggets or as seams or flakes inside quartz rock.
Industrial and Commercial Uses of Mercury
Gold is used in just about every area of human endeavor.
From jewelry and coinage to dentistry, and through to its use in electronics for plating and as reflectors in spacecraft and military armaments.
Being both the most malleable and ductile metal, it is used extensively in industry. It is found in computer circuitry, telecommunications, commercial and industrial appliances, and motor vehicles.
It would be fair to say that without gold it is unlikely that our civilization would have progressed as far and fast as it has done.
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