The unseen effect
The electromagnetic force causes like-charged things to repel and oppositely-charged things to
attract. Many everyday forces, such as friction, and even magnetism, are caused by the
electromagnetic, or E-M force. For instance, the force that keeps you from falling through the floor
is the electromagnetic force which causes the atoms making up the matter in your feet and the
floor to resist being displaced.
The carrier particle of the electromagnetic force is the photon ().
Photons of different energies span the electromagnetic
spectrum of x rays, visible light, radio waves, and so forth.
Photons have zero mass, as far as we know, and always travel at the "speed of light", c, which is
about 300,000,000 meters per second, or 186,000 miles per second, in a vacuum.