Recently, Amy and I were roving in, of all places, Merrie Olde England. In a riverside park, we came, to our surprise, upon a statue of someone that every member of the preparedness community should know. His name was Michael Faraday.
WHO WAS MICHAEL FARADAY?
Michael Faraday (1791–1867) was one of the most influential scientists of the 19th century, a self-taught English physicist and chemist whose groundbreaking experiments laid the foundation for modern electromagnetism. Born into a poor family in South London, he began with little formal education as a bookbinder’s apprentice but rose to prominence through sheer curiosity and, later, his experiments at the Royal Institution in London.
Faraday’s key discoveries include:
Electromagnetic induction: the process by which a changing magnetic field produces an electric current (or voltage) in a conductor. This enabled the development of electric generators, motors, and transformers. Faraday’s inventions of electromagnetic rotary devices even formed the foundation of electric motor technology.
The laws of electrolysis: Leading to the production of colloidal silver and other ionic solutions.
Benzene: A very important organic compound found in vast numbers of products today, including plastics, detergents, dyes, adhesives, drugs, pesticides, explosives, It serves as a critical building block (precursor) in the chemical industry.
Diamagnetism: A fundamental property of all materials where they create a weak magnetic field that opposes an externally applied magnetic field. In other words, when you place a material in a magnetic field, it becomes very slightly magnetized in the opposite direction to the applied field. This results in a weak repulsive force.
The Faraday Effect: The rotation of polarized light in a magnetic field.
These breakthroughs established the concept of the electromagnetic field and directly influenced all future scientists to develop modern electrical engineering and physics. It was largely due to his efforts that electricity became practical for use in technology.
Faraday’s work on electricity and magnetism directly led to the invention that bears his name and of which all preparedness folk should be aware: the Faraday cage. In the early 1830s, using an ice pail as part of his equipment, Faraday observed that excess electric charge on a conductor always resides on its outer surface and has no effect on anything inside (thus protecting your modern electronics from EMPs).
THE FARADAY CAGE
Faraday’s revelation stemmed from his broader research into static electricity and electrostatic induction. To test it dramatically, he constructed a 12-foot metal box covered in metal foil and mesh and insulated on glass supports. He fearlessly stepped inside and had high-voltage discharges from an electrostatic generator strike the exterior of the container, leaving him unharmed and proving that the cage completely shielded its interior. The year? Early 1836.
It was named the Faraday Cage and came to represent any enclosure made of conductive material (like metal mesh, solid metal sheets, or foil) that blocks external electromagnetic fields (EMF), radio waves (RF), Wi-Fi, cell signals, etc. It works by redistributing electric charges on its surface so that the interior remains shielded. Any properly constructed version—whether mesh, solid, large, or small—functions as a Faraday cage. A solid metal box, for example, is technically a type of Faraday cage.
This 1836 demonstration (sometimes recreated today with modern Tesla coils) showed that the cage works because free electrons in the conducting material rearrange themselves in response to an external electric field. The redistributed charges created an opposing internal field that exactly cancelled the external one, resulting in zero net electric field inside.
AN EFFECTIVE FARADAY CAGE
A good cage redirects or absorbs the damaging electromagnetic energy so it doesn’t reach the devices inside. For static or low-frequency fields, this cancellation is pretty effective. For electromagnetic waves (like radio or microwaves) and broadband transient bursts like EMPs, the effect holds as long as the mesh holes are much smaller than the wavelength of the radiations.
Construction matters a lot. It must be continuous and well-sealed (no big gaps nor conductive gaskets on doors/seams). A loose aluminum foil wrap or a metal trash can with a loose lid often provides partial protection but can leak or even focus energy in some cases.
The idea of electrostatic shielding had precursors: For example, Benjamin Franklin and others noted related effects with charged conductors in the 18th century, but Faraday built the first practical, well-documented version. More importantly, he demonstrated its implications so clearly that it earned his name.
MODERN FARADAY CAGES
Today, Faraday cages (or shields) are ubiquitous in technology and safety. Here are some common applications:
Microwave ovens: The metal mesh in the door and the conductive enclosure trap the microwaves inside, preventing them from escaping while allowing you to see the food.
Vehicles and aircraft: The metal body of a car or the conductive skin of an airplane acts as a Faraday cage, safely routing lightning strikes around occupants (if your plane gets hit by lightning, you’re generally protected).
Sensitive measurements and labs: In analytical instruments, Faraday cages block external electrical noise (like power-line hum) for more precise readings.
Specialized tech: MRI scanner rooms use them to isolate radio signals; elevators and some buildings create accidental “dead zones” for cell service; shielded cables reduce interference in electronics. Larger shielded rooms are standards for classified government and military communications.
Privacy and security: Yes, you heard right; devices exist that can attempt to read data from contactless credit cards while they’re still inside your wallet or pocket. These are known as portable RFID or NFC skimmers (sometimes called “electronic pickpocketing” tools) and can be countered with “Faraday bags.”
Faraday bags are fabric pouches lined with conductive materials. They block RFID skimming of credit cards/passports, prevent cell-phone tracking or remote wiping, and protect against data theft in secure environments.
So Faraday’s humble cage, born from curiosity about electricity as a “force”, now safeguards our hyper-connected world. From preventing kitchen radiation leaks to protecting fighter jets and forensic evidence, his work is a perfect example of how a simple principle discovered long ago continues to power (and protect) everything from power grids to personal privacy. Without Faraday’s experiments, our electrified modern life and the very devices we rely on simply wouldn’t exist.
Joe Alton MD
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