Friday, December 18, 2009


Biology instructor Tom Hermanson writes: On a wintry afternoon in December, six HHS students briskly walked across the Dartmouth College campus weaving their way among snowbanks and buildings until they reached Remsen and the Dartmouth Electron Microscope Facility. The biology students were met by Charles Daghlian and Louisa Howard of the microscope facility staff. The group divided into two rooms containing two different electron microscopes. One room housed a liquid nitrogen cooled Transmission Electron Microscope (TEM) while the other contained a Scanning Electron Microscope (SEM). The two tools use a beam of electrons to view biological samples, nano technologies, and even (top photo) individual flakes of snow!

The SEM tour started out with a look at mouse lung tissue (middle photo) including cells that contain small cellular structures called cilia. These structures looked like tiny tufts of hair, shag carpeting, or even sea anemone to some of us. These structures work to push mucus, bacteria, and dust up and out of the mouse's lungs. In the TEM room, the perspective changed and students were able to see the internal structures of the cell called organelles. Both tours finished up with a look at the pollen (bottom photo) that causes some to experience seasonal allergies. The spikes and rough exterior of different types of pollen evoked a "wow!"

This field trip is always an engaging, visual exploration into the microscopic world. We even had a new SEM visual perspective on snow as we made our way back to school along the snow-covered sidewalks.