Which Switch Switches On Which??

Sal got our noggins quite alert on this fine Monday morning.

Sal: "I think a great way to start the morning off is by doing an interesting brain teaser that gets our minds working. I always enjoyed riddles and brain teasers, so I presented everyone at Lawline with one of my favorites:
You are down at the bottom of a set of stairs, with three light switches by you. There are three light bulbs at the top of the stairs. You want to figure out which switch controls which light bulb. You cannot see any light at the top of the stairs from where you are standing, and you can only go up once to check the lights. You can also switch the lights on and off as many times as you want. What do you do to find out which switch controls which light bulb?

Answer: Turn on 2 light bulbs and leave them on for several minutes. Turn one off, and go upstairs and check the light bulbs. The light that is on corresponds to the switch you left on. There should be two remaining lights that are both off. The light bulb that is hotter corresponds to the switch you turned on then off. The remaining light bulb should be cool, and it corresponds to the switch that you did not turn on.

I feel that this riddle touched on our values of actively learning, seeking creative solutions, driven to find a better way, exuding optimism (riddles can be very frustrating at times), and taking time to help others. Everyone seemed very engaged trying to formulate the solution. "