Leonard and Sheldon notice that Howard takes any opportunity he can to remind others that he went to space. They use the scientific method to test and verify their hypothesis.
After George leaves the dinner following an argument, Sheldon is sitting outside reading a Psychology book. John joins him, and Sheldon tells him about the assignment. John asks him about it and guides him through the process of identifying the observation, the hypothesis, and the prediction.
Ada and her friends discovered some yellow plants. They do some research on why this happened and realize how the process of photosynthesis aids the growth of plants.
U.S. Marshals have tapped Richard's lawyer's phone and listen to recordings of a conversation between Richard and his lawyer. As they listen to the tapes, they make observations and use their inference skills to determine his location.