iPods and iPhones are not just another gadget. They're so universal that even calling them a 'phenomenon' is inadequate. Learn more about the 7 best ways to charge your iPod without an outlet.
WHAT'S INSIDE: PERSONAL AUDIO
- MP3 Players
We can transform musical sounds into numbers and record them digitally, although the files can be very large and take over your storage space. That's where the MP3 format comes in. Learn what MP3 files are and how they work.
AM radio, FM radio, CB radio, short wave radio, VHF, UHF -- what's it all mean? These are all different chunks of the radio spectrum. Find out all about the thousands of different uses for radio waves.