Wednesday, September 28, 2011
How cell phones work.
Cell phones communicate through "radio waves". Radio waves are like the waves on water. Imagine you are standing on one side of the pool, and your friend is standing on the other side of the pool. If you drop a small rock in the pool, it will cause little waves to go out in all directions and to the other side of the pool.
Your cell phone sends a radio wave out just like you send a water wave out. The radio wave goes in all directions until it hits a cell tower. The cell tower will then send a radio wave to the person you want to call.
Different radio waves mean different things. When you drop a big rock in the pool, it will make a big wave. Now if you drop a small rock it will make a small wave. Imagine a big wave meaning one thing and a small wave meaning something else. Let's say the big wave represents 0 and the small wave represents 1. If you send out 10 waves it could look something like this: 0010010101. This is called binary. We could make up our own language and communicate by waves.
Your cell phone tells who you are, who you want to call, and what you want to say with these 1s and 0s and tells the cell tower, who then sends it to who you're calling. This goes back and forth until one of you hang up.
Radio wave are almost instant and move at the speed of light. So there is hardly any delay.
The cell tower uses computers to sort through calls. The cell tower will assign a new radio wave to computer to handle it and goes back to looking for new calls.