94 research outputs found
Bridging Physics and Biology Teaching through Modeling
As the frontiers of biology become increasingly interdisciplinary, the
physics education community has engaged in ongoing efforts to make physics
classes more relevant to life sciences majors. These efforts are complicated by
the many apparent differences between these fields, including the types of
systems that each studies, the behavior of those systems, the kinds of
measurements that each makes, and the role of mathematics in each field.
Nonetheless, physics and biology are both sciences that rely on observations
and measurements to construct models of the natural world. In the present
theoretical article, we propose that efforts to bridge the teaching of these
two disciplines must emphasize shared scientific practices, particularly
scientific modeling. We define modeling using language common to both
disciplines and highlight how an understanding of the modeling process can help
reconcile apparent differences between the teaching of physics and biology. We
elaborate how models can be used for explanatory, predictive, and functional
purposes and present common models from each discipline demonstrating key
modeling principles. By framing interdisciplinary teaching in the context of
modeling, we aim to bridge physics and biology teaching and to equip students
with modeling competencies applicable across any scientific discipline.Comment: 10 pages, 2 figures, 3 table
Using surface integrals for checking the Archimedes' law of buoyancy
A mathematical derivation of the force exerted by an \emph{inhomogeneous}
(i.e., compressible) fluid on the surface of an \emph{arbitrarily-shaped} body
immersed in it is not found in literature, which may be attributed to our trust
on Archimedes' law of buoyancy. However, this law, also known as Archimedes'
principle (AP), does not yield the force observed when the body is in contact
to the container walls, as is more evident in the case of a block immersed in a
liquid and in contact to the bottom, in which a \emph{downward} force that
\emph{increases with depth} is observed. In this work, by taking into account
the surface integral of the pressure force exerted by a fluid over the surface
of a body, the general validity of AP is checked. For a body fully surrounded
by a fluid, homogeneous or not, a gradient version of the divergence theorem
applies, yielding a volume integral that simplifies to an upward force which
agrees to the force predicted by AP, as long as the fluid density is a
\emph{continuous function of depth}. For the bottom case, this approach yields
a downward force that increases with depth, which contrasts to AP but is in
agreement to experiments. It also yields a formula for this force which shows
that it increases with the area of contact.Comment: 15 pages, 3 figures, accepted for publication in "Eur. J. Phys."
(10/20/2011
Evaluations of People Depicted With Facial Disfigurement Compared to Those With Mobility Impairment
There are few extant studies of stereotyping of people with facial disfigurement. In the present study, two experiments (both within-participants) showed positive evaluations of people depicted as wheelchair users and, from the same participants, negative evaluations of people with facial disfigurements, compared to controls. The results of Experiment 2 suggested that implicit affective attitudes were more negative toward people with facial disfigurement than wheelchair users and were correlated with evaluation negativity. Social norms were perceived to permit more discrimination against people with facial disfigurement than against wheelchair users. These factors could help to explain the evaluative differences between the two disadvantaged groups
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