Being a 21st-century lady or man, you have no doubt texted today. You did it blithely and happily, perhaps only vaguely aware of the technology involved (something about ... networks? The Cloud?).
Let's focus on one technology you might've used during your texting that you probably thought nothing of. It happened when you, unsatisfied with the vertical tyranny of your smartphone screen, turned your phone to a horizontal position. Easy as pie. Suddenly, your screen oriented horizontally, giving you the wide lines you needed to fully express to your brother how great the new Batman movie is. That simple act requires a technology we use all the time without knowing it: an accelerometer.
An accelerometer measures the accelerating movement of an object. It can measure speed and motion, and thus is able to tell the angle at which an instrument is being held. Sensors in the accelerometer "talk" to the small computer in your phone and ask it nicely to please make the visual output look wide instead of long. This technology is also used in your Wii remote, so thank your accelerometer after your next virtual tennis game.
Next up, a close relative to the accelerometer that you would be in trouble without.