ABSTRACT
The Internet consists of millions of computers connected in such a way that they can exchange information (i.e., communicate). They do this using electromagnetic (EM) waves, which are carried either through the air, through metal wire, or through thin glass fi bers, to the receiver’s computer. For example, the digital data that you download from the Internet might be sent from one city to another using light waves in an optical fi ber. Then it might be converted into voltages and sent along a copper wire to a wireless router, where it would be converted into radio waves and broadcast to your computer. The data that you downloaded could represent music. After those data are reconstituted into an analog form, they can drive a stereo speaker, creating sound. The sound waves travel through the air and fi nally arrive at your ears. We see that the concept of waves plays a key part in these phenomena. We will begin this discussion with the topic of harmonic motion and waves in general, and then move on to sound, radio, and light waves.
