Nah, the color of the orb is irrelevant. The whole point is that the words are randomly generated and randomly assigned to each of the pipes. You just need to figure out which word is connected to which pipe. You'll know once the light goes green. There's also two extra words that don't belong to any pipe.
Edit: The challenge is to remember. 5 words, 3 of which are assigned. 1 pipe 1 word. Put the orb into the pipe that is connected to the right word.
Edit2: I'm sorry for communicating that poorly in the tutorial of the game.