  The research presented in this thesis was motivated by the need to improve
introductory physics courses. Introductory physics courses are generally the
first courses in which students learn to create models to solve complex
problems. However, many students taking introductory physics courses fail to
acquire a command of the concepts, methods and tools presented in these
courses. The reforms proposed by this thesis focus on altering the content of
introductory courses rather than content delivery methods as most reforms do.
  This thesis explores how the performance on a widely used test of conceptual
understanding in mechanics compares between students taking a course with
updated and modified content and students taking a traditional course. Better
performance by traditional students was found to stem from their additional
practice on the types of items which appeared on the test. The results of this
work brought into question the role of the introductory physics course for
non-majors.
  One aspect of this new role is the teaching of new methods such as
computation (the use of a computer to solve numerically, simulate and visualize
physical problems). This thesis explores the potential benefits for students
who learn computation as part of physics course. After students worked through
a suite of computational homework problems, many were able to model a new
physical situation with which they had no experience.
  The failure of some students to model this new situation might have stemmed
from their unfavorable attitudes towards learning computation. In this thesis,
we present the development of a new tool for characterizing students'
attitudes. Preliminary measurements indicated significant differences between
successful and unsuccessful students.
