The formulation of a scientific prediction by students in college-level laboratories is proposed. This activity will develop the students' ability to apply abstract concepts via deductive reasoning. For instances in which a hypothesis will be tested by an experiment, students should develop a prediction that states what sort of experimental outcome is expected, consistent with the hypothesis being tested. The concept of a scientific prediction is presented and distinguished from common usage of the term. Using one of Lavoisier's experimental tests of the oxygen and phlogiston theories as an example, reasoning with the use of prediction and without the use of prediction is presented in a classic crucial experiment. This approach enables students to compare data and prediction directly prior to reaching a conclusion. Finally, three typical conclusions are presented based on whether data and prediction agree.