Ok. I have a riddle as well. There is a room with a door that is light tight etc… Inside the room there are three light bulbs on the wall. Outside the room there are 3 light switches on the other side of the wall. You start from outside and the door is closed. You can only go in the room once. How do you know which light switch turns on which light bulb?
Four. One to screw in the light bulb, and three to turn them around.
read the labels conveniently attached to the switches.
here is my riddle: why would you want to go in the room to begin with? it doesnt sound particularly fun.
Easy:
Turn two on at different intervals and see which one is hot and which is not so hot.
After reading Spacks answer.
Hilight below:
Turn one on for a while (long enough to get hot), turn it off and turn another one on. When you go in one light will be on (that ones easy to figure out) and one light will be off but hot (that’s the first switch) and the one that not hot is the switch you never touched.
Cool problem.
spack is on the right track. I think that might work but it depends on the bulbs. You would have to know approx. how quickly the bulbs cool or heat up to do it that way…But the answer is close to that.
What do you mean ‘on the right track’? 
That IS the answer.
You turn on one light, wait ten minutes or more, then turn on another light and walk into the room. There will be a hot bulb, another bright bulb which will be warm and one that is off.
You mean there is another answer I presume.
Did anyone even look at mine? I think it’s right too, a little bit more right then Spacks if I do say so myself (and I do).
miltownkid- Smartie pants. Good one!
Our answers are almost identical.
My answer is simpler because [spoiler]you don’t need to turn any lights off.
Turn on one, wait 10-15, then turn another - you’re done.[/spoiler]
:bravo: Noice
Spack, please use the code. Coding it white does not hide your answer.
OK! I did wonder how people made their posts invisible like that! Thanks.