Electromagnetism Today

Courtney Kroll Per 5

Pioneers in Electromagnetism


  • — Heinrich Hertz: Heinrich has been one of the main contributors in electromagnetism.


  • —He started doing experiments with electromagnetic waves going through loops of metal wire, eventually he found out that electromagnetic waves and light waves were identical.
  • —He found out the unit of measurement for these waves and named them “Hertz”

Electromagnetic Induction

  • —This is the production of a potential difference across a conductor when it is exposed to a varying magnetic field.
  • —This property allows mechanical energy to be converted to electrical energy and vise versa. Motors consume electrical energy and convert that to produce mechanical energy.

Why Care About Electromagnetism?

  • Credit Cards-the strip on the back of the credit card is made up of magnetic particles that contain information. Any contact with a magnet or magnetic field can cause the strip to become demagnetized. Exposure to magnets can cause the particles in the strip to rearrange, making the card unreadable. John Biggins invented the credit card. He created it for the Flatbush National Bank in New York.
  • Television-a beam of is used to light up the phosphors on the screen. When you plug it into the wall voltage is able to be sent through the wires and electrical energy powers the television. John Logie Baird, who was a Scot living England invented the television in 1925.

  • —Scrap Metal Crane- it is a giant electromagnet itself commonly used in junk yards to dispose cars.
  • —MRI- An MRI is based on physical and chemical of nuclear magnetic resonance, a technique used to gain information about the nature of molecules.
  • VHS Tapes: They use encoded magnetic information. The VHS was created by the AMPEX corporation in 1956
  • Microphones: The sound waves strike the diaphragm and move it backwards and forwards at the same frequency as the sound. The moving diaphragm moves the coil backwards and forwards which induces a changing current at the same frequency as the sound.

    —The inventor of the microphone was Emile Berliner. He was born in 1851 in Hanover, Germany. His other inventions included a loom and an early prototype of the helicopter.

  • Compass: A magnetic compass consists of a small, lightweight magnet balanced on a nearly frictionless pivot point.

    The dry compass was created in medieval England in the early 1300’s, there is no individual

    inventor specified

  • Compass: A magnetic compass consists of a small, lightweight magnet balanced on a nearly frictionless pivot point.

    The dry compass was created in medieval England in the early 1300’s, there is no individual

    inventor specified

  • Magnets on the refrigerator: They have opposite magnetic forces. Missouri, invented the first refrigerator magnet. He obtained a patent for his device in the 1970s. The patent was for colored, cartoon magnets for decorative purposes.

The Barcode

  • —A magnetic barcode is placed on your wrist, when it is scanned it sends out special readings in a certain order that only is the same for each individual person allow people to be easily distinguished when going to public events and allowing their ages to be checked at movies.