The Three Switches-Brain teaser

Riddle 
You have three switches outside a room. Each switch controls one of the three bulbs inside the room. All the switches are in the "off" position, and you can't see the bulbs from the outside. How can you figure out which switch controls which bulb if you can only enter the room once?

    1. Turn on the first switch and leave it on for a few minutes. 2. Turn it off and immediately turn on the second switch. 3. Enter the room: - The bulb that is on is controlled by the second switch. - The bulb that is warm but off is controlled by the first switch. - The bulb that is cold and off is controlled by the third switch.