Degaussing
Here is your word of the day: degauss, meaning to remove or neutralize something’s magnetic field. It comes from the word ‘gauss’, which is a unit of measurement of magnetism, named after mathematician Carl Friedrich Gauss (1777-1855).
And here is how copper and degaussing saved lives during WWII!
At the start of WWII, sea (aka naval) mines were contact mines, meaning they had to come into direct contact with ships to detonate.
However, Germany quickly started deploying more sophisticated mines that exploded when ships got close to them, but without requiring actual contact. These mines detonated when they detected an increase in the magnetic field as a result of a ship passing close to them. As a large ferrous object (i.e. a ship made of steel) passes through Earth’s magnetic field, it concentrates the field over it. When the sensor in the mine detected this concentrated magnetic field, it triggered the mine and the nearby ship was damaged by the shockwave of the explosion.
One of these mines ended up on the mud flats in the Thames Estuary at low tide in November 1939. This allowed the British to take it apart and examine this new trigger system.
To protect ships from these new magnetic mines, the British navy started degaussing ships. It installed copper wire around the circumference of ship hulls and passed electric current through the wire. This created a magnetic field that cancelled out, or at least significantly reduced, the magnetic field of the ship, making it “invisible” to the sensors of magnetic proximity mines.
Degaussing systems became widely used by the British and by D-Day, June 6, 1944, over 18,000 vessels had been protected in this way.
The bigger a ship was, the more copper needed to degauss it. For example, the Vanguard battleship (pictured below) required twenty-eight miles of copper wire which weighed 30 tons.
Canadian Charles Goodeve, who worked with the British military during WWII, played a key role in developing degaussing and other innovations during the war. He also invented the word “degauss.”
Today, copper is arguably the most important metal for clean energy because it is used in most electrical wiring. The more clean energy we produce, the more copper we will need.
