In 1752 the American inventor Benjamin Franklin created the lightning rod. He discovered the conduction of electricity while flying a kite with a metal key. During a storm, he noted that the electricity seemed drawn towards the key.
This led him to conclude that the power of the electrical storm traveled to metal. This was one of the first experiments proving that metal conducts electricity.
Why are metals such good conductors of electricity, though? Why are certain metals chosen over others? What causes this to happen?
Today we hope to help you understand all of the intricacies of electric conduction!
What Is a Conductor of Electricity?
Electrical conductors are materials that transfer electricity through them. These materials have a favorable molecular structure. When these structures exist, it permits the free movement of electrical charge.
This means the material does not impede the flow of the electrical currents. Some materials have a more solid structure. Others have more volatile molecular structures and are less inhibitive to electrical flows.
Materials that are good at conducting electricity are known as a conductor. Materials that consume electricity and do not permit it to travel are referred to as insulators.
Of course, the study of electricity, electrical circuits and systems is not trivial. This article will serve as a good basic foundation of why certain metals are better conductors of electricity than others.
What Makes a Good Conductor?
A good conductor has a molecular structure that is favorable to the transmission of power. The basic reason for this is the movement of the electrons within the substance.
Metal is a good conductor of electricity, but some metals are better than others. Metals have a very strong bond between atoms, which prevents them from melting during heating. But, it also has numerous moving electrons throughout the structure.
This is what makes metal such a unique substance when it comes to electricity conduction. The strong structure permits it to remain solid throughout the electrical power surge. But, it is malleable enough to permit the electrons to carry the power through it.
Some metals have a large amount of free-roaming electrons. Metals such as steel and copper have a large number of free-moving electrons within them. Copper is the original best conductor of electricity.
Copper is commonly used to cover electrical wires. It is an adaptable and easily bent and malleable metal. Copper is a soft metal that allows electricity to flow uninhibited. This is why it is commonly used on electrical wiring and in electrical conduction.
Copper has a high amount of free-moving electrons. The high number helps to move electricity throughout the substance. Copper is also one of the cheaper methods of coating electrical wires. This is especially true for household and small home appliances.
Other excellent conductors of electricity include gold and silver. These metals have a solid and stable structure that still permits electrical flow. They are well-liked for their capacity to retain their shape and colors. But, of course, they are more expensive than copper.
Why is Gold a Good Conductor?
Gold is not as good at conducting electricity as copper. But, gold has a very high tarnish resistance. This is actually a very important factor of metal conductivity.
As metals corrode, they lose their potency to carry electrical charges. This is why gold is commonly used to coat wires and other easily damaged parts.
Obviously, copper is more popular because it is not as expensive as gold. If it was purely the efficacy, though, gold would be more popular.
Silver is the Best Conductor
Silver is actually the best conductor of electricity. It tops both copper and gold in its conductivity. So, why don’t we see it more often being used in electronics?
This is because, unlike gold, silver has a very high tarnishing rate. Silver corrodes very easily and does not resist wear very well. Corrosion disrupts the flow of electricity and prevents it from flowing to the desired place.
For these reasons, silver is a great conductor. But, it’s not too popular in electronics.
What Makes Something a Bad Conductor of Electricity?
Some examples of a bad conductor of electricity are wood and stone. The reasons stone and wood are not good conductors of electricity is their structure. They are solid structures without free-flowing molecules.
Substances such as stone are insulators. Rather than permitting the electrons to move freely, they absorb the energy. When they absorb the energy, it may heat the substance up. But, the electricity with not travel through the substance as it does in metal.
Other substances such as trees or wood are a little more complicated. Trees do have a level of liquid content inside of them. Water is an excellent conductor of electricity.
If a tree is struck by lightning, the energy tends to flow through the trunk and into the earth. Sometimes the electricity is so hot it causes the water and sap to boil. This acts as an explosive substance from the heat and boiling liquids.
Often times the trees crack or burst as a result. However, wood is not a good conductor or electricity. This is part of the reason why the trees tend to burst from the pressure. Wood is a very solid substance that naturally acts more as an insulator than a conductor.
If it wasn’t for the water and sap inside of a tree, the lightning would absorb into the wood.
Different Metallic Bonds
As discussed above, the structure of the metal is what makes them such good electrical conductors. Metal has a way of both being a solid structure while permitting electrons to pass through.
Metals have different forms of metallic bonds. This impacts how the electricity flows through the metal. As a result, some metals are better than others at conducting electricity.
We will explore some of the best metal conductors in the next major section. First, we will explore various metallic structures and how they bind together. This heavily impacts the transfer of electricity between substances.
What is an Ionic Bond?
An ionic bond refers to how electricity travels from metals to non-metals. But, more specifically, it refers to the charge between differently charged atoms.
Some are negatively charged, and some are positively charged. The bonding of this element creates a new substance. Some examples of ionic bonds are sodium fluoride and lithium fluoride.
What is a Covalent bond?
Covalent bonding is the sharing of atomic particles between two substances. Covalent bonding means that one substance gives atomic matter to another. And vice-versa.
This exchange occurs between an organic and inorganic substance. When this occurs, it creates a new substance. One popular example is carbon monoxide. Other examples include sugar and water.
The atomic structures of these substances lend them to covalent bonding.
What is a Metalic Bond?
Metallic bonding occurs between positively charged atoms. This static electricity charge brings atoms together in a bond.
This bonding is what makes a metal more malleable and better for electrical work. The more flexible a metal, the easier it is to use for different electronic devices. But, it also allows differently charged atoms to create a bond for improved electrical flow.
What is Electrical Resistivity?
Electrical resistivity is a measure of how strongly a material resists electric current. If the material has a lower resistivity, this means it will conduct electric current more easily than a material with a high resistivity.
The resistivity of different size conductors at different temperature ratings are as follows:
If we know the resistivity of a conductor we can calculate the resistance of that conductor given its length and Circular Mil Area (CMA). The equation relating them is as follows:
Where p (rho) is the resistivity of the conductor, l is the length of the conductor, and CMA is the circular mil area of the conductor. We recommend you watch our video for deeper insight into this topic.
What is Ohm’s Law?
Ohm’s law is named for the German scientist who first discovered its properties. Georg Ohm found that the movement of electricity through a substance relates to the voltage used.
Ohm’s law connects voltage with the flow and resistance of electricity. The law studies the connection between the capacity of electricity to travel through a substance.
The importance of this law is its connection with the electrical flow. A voltage of electricity can impact the flow of electricity. A stronger current can disrupt the organization of molecules within the materials. But, a good conductor permits the movement of the voltage with ease.
Other substances create a barrier or resistance. How this works will be explained in more detail below.
Why Are Homes Made With Metal?
With all of this information, you might be wondering why homes aren’t made with insulators? They are, in some fashion. Builders typically make homes with brick, wood, or stone. But, usually, siding is aluminum or metal siding. And they have metal parts on the roof.
The way around this is with a lightning rod or electrical conductor. These metal rods serve as an attractor to electrical storms. This helps prevent fires caused by electrical storms. When the electrical charge strikes, the electricity flows down a wire and down into the earth.
This is one of the strange facts about electricity and electrical conductors. Sometimes, it is better to draw the electrical power willingly. This way, you have some control over where it ends up. Otherwise, you are at the mercy of hoping lightning will not strike your home.
Prior to the invention of the lightning rod, many wooden houses were lit on fire by lightning. Dry wood and stone may not conduct electricity, but lightning can damage them. This is why it is better to attract it willingly and direct it elsewhere.
Why Good Conductors of Electricity Matters
Good conductors of electricity help ensure the efficient use of electrical power. Coating wires with a good electrical conducting metal may seem counterintuitive at first. You might think it is dangerous to use a conductor on electrical equipment.
But, having a good conductor helps ensure it transfers efficiently and safely. It is safer to use a good conductor of electricity than to struggle to move the power.
At PLCGurus, we are energy experts! We always provide applicable and accurate information. Contact us with any questions or concerns you may have!