[dboy]

temperature is the measurement of movement of atoms. How on earth does ones heat receptors in the body determine how quick atoms are moving, within a certain substance (cold water), and differentiate from hot and cold??

any ideas? 

[arit]

I think you should consider temperature as a macroscopic property, instead of a property of single atoms.

[SheVa]

think molecule collides with heat receptor. the higher temperature the more frequency of molecule collides with receptor making a friction or "break" some part of receptor. so, its not the receptor can measure how fast a molecule move but the molecule collide with the receptor giving its kinetic energy to the receptor as a signal.