"There is a growing realization that nurturing scientists for the 21st century requires engaging students in the processes of doing science. For students to be engaged in the process of doing physics, they need to learn to think like a physicist... For example, when solving an experimental problem, a physicist needs to decide what features of the problem are relevant and which features can be ignored, how to represent the problem in different ways, including mathematical expressions, how to use available equipment to collect necessary data, how to analyze the data, and how to evaluate the results.