You are in a room with 3 switches. These switches control 3 light bulbs in another room, and you cannot see the bulbs while you are in the room with the switches. Your task is to figure out which switch controls which bulb. However, you can only enter the room with the bulbs once.

Objective:
Determine which switch controls each bulb using only one trip to the room with the bulbs.

Solution:

To solve this puzzle, you need to use the properties of light bulbs: they emit light when switched on, and they get warm after being on for a while. By using this knowledge, you can determine which switch corresponds to which bulb.

Step-by-Step Solution:

Step 1: Turn on the First Switch

• Flip the first switch (Switch 1) to the "ON" position.
• Leave it on for a few minutes. This will allow the bulb it controls to become warm.

Step 2: Turn on the Second Switch

• After the first switch has been on for a while, flip the second switch (Switch 2) to the "ON" position, but do not wait as long. Only leave it on for a short time, so the bulb it controls turns on but doesn’t get too warm.

Step 3: Leave the Third Switch Off

• Leave the third switch (Switch 3) in the "OFF" position. This will ensure that the bulb it controls remains off and cool.

Step 4: Go to the Room with the Bulbs

• After you have followed these steps, go into the room with the bulbs. Now you can identify which switch controls each bulb based on three conditions:
  1. The bulb that is on and warm is controlled by Switch 1 (since it was left on for a long time).
  2. The bulb that is on but cool is controlled by Switch 2 (since it was turned on for only a short time).
  3. The bulb that is off and cool is controlled by Switch 3 (since it was never turned on).

Final Answer

• Switch 1 controls the bulb that is on and warm.
• Switch 2 controls the bulb that is on but cool.
• Switch 3 controls the bulb that is off and cool.