Freshman Seminars
15 students meeting 2 hrs/week
Each week students explore a different topic such as
waves, tornadoes and tides. Each class includes a number of hands-on,
‘mind-on’, demonstrations. The fluid dynamics is developed, and then an
observational puzzle is posed: for example, what factors make tropical
cyclones in the Bay of Bengal so deadly?
A tornado vortex. This
remarkable flow is converging from the sides, in a rotating cylinder of
water; it is drawn out by a sink
at the top. Dye marks the spiral upward flow
characteristic of the vortex, while fainter dye shows
the outer regions of rotation.
Jet Streams, large-scale atmosphere/ocean dynamics.
A cold central cylinder drives meridional flow and Coriolis forces turn
this into east-west jets. Both ocean and atmosphere have large scale
horizontal density differences which cause curled-up jet streams and 'Gulf'
streams. For a freshman class one can demonstrate the sea of eddies
and compare with satellite images of both air and sea.
Bathtub vortex. Withdrawing water from an oulet and injecting
it with some swirl gives a familiar, intense vortex that can be studied
as a simple illustration of fundamental physicsof angular momentum and
vorticity. Two ping-pong balls are trapped in this one.
Demonstrating stratified flow. Density differences, though slight,
are perhaps the most important physical property of the ocean, for life
on Earth. Biological communities depend upon nutrients from the deep or
from river inflow, and on sunlight from above. Density gradients control
the locations and productivity of both coastal and open ocean regions.