Why do magnets mess up television screens? What is the science behind it?
A CRT television creates an image by directing a stream of electrons with electric fields. When you bring magnets near the screen the electrons experience a force which deflects them therefore destroying the image.
A moving charged particle creates a magnetic field and similarly a magnetic field creates a force on a moving charged particle.
A TV (at least one with a glass tube, not a Plasma or LCD) works by firing a stream of electrons from a gun at the back to light up the screen. Since electrons are charged the magnetic field bends the beam.
ps. Be careful, most color TVs have a metal sheet just inside the glass to hold the color filter. If you hold a strong magnet too close you can permanently magnetize this sheet and make the picture permanently distorted.
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