Tilting screen functions on mobile phones

[bigfoot3000]

I have a function on my phone that allows me to tilt my screen which makes the image on the screen face another direction. I notice many other phones have this function which allow you to tilt or shake the phone to use a function.What is it in mobile phones that senses you tilt them allows them to do this?

[ChuckFickens]

http://en.wikipedia.org/wiki/Accelerometer

[bigfoot3000]

Thanks chuck that explained everything.