Whoever said radio was dead clearly heard nothing about the internet. Wireless internet streams your favorite T-Swift songs for you the same way it does on your favorite alt. pop FM station: through radio waves. If you want to read about those and all other waves (potentially including "the wave"), check out the Physics learning guide.

Radios work by blasting modulating sine waves (because a simple sine wave is just a wave; if you mix up when the sine wave gets sent, one sine wave period can equal one and the other can equal). If you decide to use AM or FM, you aren’t just picking an arbitrary label for the same thing—you're picking the modulation style that stations use on their waves.

All waves rely on two things: amplitude and frequency. AM uses amplitude modulation and FM uses—wait for it—frequency modulation. By changing one and leaving the other constant, they can control what exact information is being sent instead of making radios guess at what's going on.

Wireless, on the other hand, uses digital modulation, which can cheat a little because it only has to send binary information. In this situation, one phase of a sine wave equals a bit. Say your sine wave's going along, translating into a 1. If that sine wave switches its period by 180° (making it essentially cosine, if you want to call it that), it's also switching the number it's representing, making the wave now equal to 0. Using this technique, wireless internet cards in your laptop and the wireless routers in your house or school all convert your binary data into radio waves at typically two frequency bands, 2.4Ghz and 5Ghz.

More devices operate on the 2.4Ghz band, but its lower frequency means the signal has longer range, so casual Wi-Fi usage that doesn’t send tons of data works fine here. Since the 5Ghz frequency is higher—making it lower range—fewer devices operate on it, making it the best option for things that send a lot of data—like Netflix streaming.

Not bad...for a radio, at least.

(Source 1, Source 2, Source 3, Source 4, Source 5, Source 6, Source 7)