The code for the laboratory to get the Moon Tears changes from game to game. It is determined by the order you find the five bomber kids. Each of them have a number on their back. The code is their numbers in the order that you found them. To find out what the code is, you must first pop the balloon with a bubble, arrow, or Zora Link's boomerang (preferably the bubble). Then, talk to the small kid who was trying to pop it. Tell him you want to try his test, and if you can locate and catch all five kids before the next morning you will receive the code. To catch a kid, run up to him. When he starts to run away, stand still. After running a short distance, he will stop running. When he stops, shoot him with a Deku Bubble Attack. The kid should be caught. Note: The kid carrying the Cucco must be shot once before he starts running, then again after he stops.