premise: A man waiting for the results of the machine after doing an experiment in his laboratory. hypothesis: A boy displays his volcano at the science fair.
contradiction: He first refers to the person as a man, and then continues to to refer to the person as a boy. Although both actions are science-related, the man is waiting for results of an experiment in a laboratory, while the boy displays his volcano at the science fair (implying he is at some kind of school).