What is the ELECTROMAGNETIC SPECTRUM

Summary

• The electromagnetic spectrum consists of electromagnetic (EM) waves, which are oscillations of electric and magnetic fields.
• In an EM wave, the electric and magnetic fields are at right angles to each other, and both are perpendicular to the direction the wave travels.
• The spectrum is arranged by frequency—the number of wavelengths passing a point each second. Frequency is measured in hertz. The video gives a broad range, from about 300 kHz to 3 × 10²¹ Hz.
• EM waves can travel through air, solid materials, and a vacuum. They do not need a medium, so they can travel through outer space.
• Moving across the spectrum toward higher frequencies, wavelengths become shorter. The video illustrates this with approximate comparisons:
  • Radio waves: roughly the size of a soccer field
  • Microwaves: roughly the size of a baseball
  • Visible light: roughly the size of bacteria
  • X-rays: slightly larger than a water molecule
  • Gamma rays: roughly the size of atoms
• Visible light is divided into colors: red has the lowest frequency, while blue has the highest.
• The spectrum has many everyday uses, including radio and music, visible light, microwave ovens, and medical imaging.

Speakers and Sources

• Speaker: An unidentified narrator
• Source/channel: MooMooMath and Science