Women in Physics Canada Conference - 2011

A gel that has similar thermodynamic properties to human tissue is necessary for determining the safety of implanted medical devices during magnetic resonance imaging (MRI). One particular gel recommended by the ASTM standard (F218209) is the polyacrylic acid (PAA) phantom. In this work, PAA mixtures were characterized by measuring viscosity (as a function of shear rate), electrical conductivity, thermal conductivity, and elastic and viscous moduli (as a function of frequency). Experiments compared samples with blend times between 30 seconds and 9 minutes, and measurements were taken over a period of weeks to document the aging process in the phantoms. Results suggest that 3 minutes or more of blending 500 mL quantities causes the sample to transform from a gel (which has a well-defined yield stress) into a viscous liquid. The same transformation was observed in a single sample over a  period of two weeks. These results are important because the current ASTM standard does not specify blending time in detail. It is therefore possible that variability in the gel preparation methods could affect the results of experiments to determine the safety of implanted medical devices. These results will help to strengthen the ASTM standard procedure in future revisions.

Physics Education Research (PER) is a blossoming subfield of physics that is changing the way students become physicists. Our research involves the transformation of the lab portion of a first-year enriched physics course through the implementation of “invention activities:” discovery-learning activities that ask students to “invent” a solution to a problem before being taught the expert solution. The combination of invention activities and tell-and-practice methods has been shown to lead to better student learning and performance on transfer tasks, as compared to tell-and-practice methods alone (Roll, Aleven & Koedinger, 2009; Schwartz & Martin, 2004). In addition, scaffolding invention activities using domain-independent metacognitive prompts can support students through the invention process, leading them to attend to more features of the domain and reason at a deeper level (Roll, Holmes, Day & Bonn; submitted). Our current study further investigates this theory by expanding the treatment across a four-month term and using faded levels of scaffolding. Using interactive learning environments (ILE), five inventions in the domains of statistics and data-analysis were given to students and various assessments were administered to measure performance on domain-level knowledge and “invention skills.” I will present preliminary results from this and previous studies.

In recent years there has been an increase in the number of women in all academic levels in physical and applied sciences in Canada. Despite the modern feminist movement the number of women in physics continues to be less than the number of men, particularly in higher and leadership positions. As there is no rational reason for women to trail men in achieving new scientific discoveries or excel in academic teaching, the cause of this is attributed to existing gender biases in the perception and practice of science. Thus increasing the number of women in physics as well as emphasising their relevance in physics has emerged as a women

What is the Universe made of? Recent observations suggest surprising results: not only most of the matter in the Universe is dark and unconventional but, more surprisingly, the major component of the Universe may be in the form of 'dark energy' -- a form of energy that opposes the pull of gravity and causes the expansion of the universe to accelerate. By combining recent observations of clusters of galaxies, distant supernovae, and the cosmic microwave background, we find evidence for a Universe that has only 5% 'normal' baryonic matter, 20% non-baryonic dark matter, and 75% 'dark energy'. The observations suggest a Universe that is lightweight, with only 25% of the critical mass-density needed to halt the Universal expansion, and a geometry that is flat with no space curvature. The observations of the dark side of the Universe and their implications will be discussed.