Electricity can be static, like
what holds a balloon to the wall or makes your hair stand on end. Magnetism
can also be static like a refrigerator magnet. But when they change or
move together, they make waves - electromagnetic waves.
Electromagnetic waves are formed when an
electric field (which is shown in blue arrows) couples with a magnetic field
(which is shown in red arrows). Magnetic and electric fields of an
electromagnetic wave are perpendicular to each other and to the direction of
the wave.
James Clerk Maxwell and Heinrich
Hertz are two scientists who studied how electromagnetic waves are
formed and how fast they travel.
