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A method to characterize the bulk hydrated properties of soft polymers and hydrogels, whose moduli are in the low MPa regime, using the pressure-bulge technique is presented. The pressure-bulge technique has been used extensively in the characterization of thin films, particularly for the case of metals. The extension of the plane-strain and circular bulge techniques to determine the Young's modulus and Poisson's ratio of bulk latex and silicone rubber sheets are shown here, in addition to the viscoelastic behavior of 5% agarose gels in the time domain using relaxation tests. The membranes are clamped between two stainless steel plates that are connected to a liquid pressure chamber. A syringe connected to a linear actuator causes changes in the pressure and displacement, and a pressure sensor and confocal displacement sensor are used to monitor these changes in real time. The theory presented converts the measured pressure and displacement data into stress and stretch data, using a geometrically nonlinear analysis, and the elastic/viscoelastic properties are then determined from this data. The results from the bulge tests are compared with data from uniaxial tension tests on hydrated specimens, and the data comparison with respect to each of the materials tested show good agreement between the two measurements. These results show promise regarding the use of pressure-displacement techniques to characterize other soft material systems, including biological polymers and tissues, as well as cell-to-matrix and cell-to-cell interactions under varying mechanical loading conditions of cell substrates.

Many outreach programs offered by universities provide pre-college students an opportunity to explore careers in science and engineering. For high-achieving students who already have an interest in these areas, these types of programs can introduce students to advanced concepts, develop their understanding of scientific methodologies, and expose them to science and engineering research. One such program, the Young Engineering and Science Scholars (YESS) Program, is a three-week summer residential program created to bring exceptional high school juniors and seniors from underrepresented minority groups to study at the California Institute of Technology (Caltech). The program is intended for motivated students who wish to broaden their knowledge of science and engineering beyond that offered by their high schools. During the three-week program, students take science courses and are exposed to laboratory tours, faculty lectures, and college admissions workshops. The creation and implementation of an integrated curriculum for a physics and introductory engineering YESS course is the focus of this paper. The 2007 physics and engineering curriculum was designed with four main objectives in mind: to ensure that students had a conceptual understanding of mechanics fundamentals, to challenge students to use their knowledge of mechanics in an engineering design competition, to expose students to advanced topics in physics, and finally to provide students with an opportunity to conduct guided research. Several assessment methods were used to determine if this type of fast-paced and integrated curriculum would be successful in achieving the aforementioned objectives. These include a preand post-examination, student performance evaluations, and student surveys and feedback. This paper provides a description of the program, a discussion on the teaching philosophy, a breakdown of the physics course structure, and a presentation of results obtained from the assessment. From these r