A SCience Odyssey Radio Transmission

How is a Radio Wave Emitted?

Diagram of atoms within a wire showing movement of electrons between atoms

OK. So we have a signal that is sent to a radiosmitter's antenna. How does that signal get from the antenna to the air?

Let's first take a look at the signal. The signal is an electic current, and every electric current is actually electrons moving in a wire.

Wire is made of metal, usually copper. All of the atoms that make up the wire have something in common -- each has one or two electrons in its outer-most shell.

These electrons do not have a strong bond with the rest of the atom. In fact, it takes just a slight amount of energy to push the electron away from its atom.

But if you have enough energy, the outer electrons from all of the atoms will move at once. They will each travel from one atom to the next atom, and so on.


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