Recent Academic year SMILE write-ups have been placed on the SMILE home page. Sign on to the internet and check them out at the URL http://www.iit.edu/~smile/. The write-ups are being put first on my home page, http://www.iit.edu/~johnsonp/ and then transferred over to the SMILE site.

          OUR NEXT MEETING...
                             ...will be April 11, 2000
                                        4:15 p.m.
                                        152 Life Sciences Bldg
          AT OUR LAST MEETING (Mar 28)...

Ben Butler (L Ward School)
showed us "C-Spectra." (handouts) He set up a discharge tube apparatus on the table, and plugged a hydrogen discharge tube into it. The tube has hydrogen in it, and a high voltage is applied to electrodes at its ends, which produces excited (high energy) hydrogen atoms, resulting in the emission of light. But the light was not white light which has a continuous spectrum of color. The hydrogen atoms emitted light of only certain colors, and we could see the separate colors by viewing the light through a holographic diffraction grating (C-Spectra) film. We saw colored spectral lines of red, blue and violet from the hydrogen. When Ben replaced the hydrogen tube with one containing mercury atoms, we saw spectral lines of yellow, orange and violet. A tube containing water molecules produced the same spectral colored lines as hydrogen (surprise?!), and a tube with argon showed us red, orange, blue and violet lines. The handouts gave some explanation and descriptions of spectra obtained from various elements (gases) within the tubes.

Ben showed us an absorption spectrum next. He shined white light through a solution in a transparent container, and we viewed the light coming through with our C-Spectra holographic diffraction gratings. Sure enough! When the white light was spread into a continuous rainbow spectrum, dark bands appeared in place of the colors that would normally be there in the spectrum. Those particular colors were being absorbed by the solution, and could not get through to be observed by us. Very nice, Ben! Thanks!

Val Williams (Bass School)
showed us the effect of music on doing delicate tasks. As an example, a task was picking plastic "bones" out of recesses in a "human body" with tweezers. Val's subject, a 10-12 year old boy, wore headphones, and we compared his efficiency at this task with different kinds of music fed into the headphones. We saw that the efficiency appeared to be affected by the type of music. And finally, Val and his assistant did a "rap" song on Evolution, which most seemed to enjoy. Interesting stuff, Val!

WHAT WILL HAPPEN AT OUR NEXT MEETING?!