Electromagnetic Radiation
Light, Sound and Waves

Microwave miscellany

Stories from Physics for 11-14 14-16 IOP RESOURCES

  • Salty foods may warm up slightly more quickly than food without seasoning in a microwave oven. Although the main mechanism by which food is heated is through the absorption of microwaves by water molecules, in solution, Na+ and Cl- ions experience a force due to the changing electric and magnetic. Hence salty water will heat faster than pure water in a microwave.
  • Melting ice in a microwave oven is a slow process because ice has different dielectric properties from liquid water and is almost transparent to microwaves.
  • The reversing direction of microwave turntables is not a feature designed to encourage uniform heating, as is sometimes believed. In a response to a question in the New York Times, Robert J. Thomas, a professor of electrical engineering, pointed out that the change in direction of rotation occurs because the motors used in microwaves are typically cheap and require a torque to start moving when starting from stationary. The turntable is usually pressed against the load from the last rotation so starts to turn in the opposite direction.

References

Electromagnetic Radiation
can be represented by The Electromagnetic Spectrum
has the special case Visible Light
is used in analyses relating to X-Ray Scanning
features in Medical Physics

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