August 2003 S M T W T F S           1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30  July 2003 S M T W T F S     1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31     Daily Logs This material is based upon work supported by the National Science Foundation under Grant No. 0230236. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Please select a name below to see the individual log. Bob McCarthy | Gerhard Behrens | Andreas Münchow Log - July-30-2003 by Robert McCarthy Previous | Next Celebrity Robert McCarthy Lee Narraway is on the deck! Lee Narraway is on the deck! Quick, get your cameras! No, there are no paparazzi onboard, but anyone and everyone with a camera is following her. Why? Who is Lee Narraway you might ask. And why is everybody scurrying for their cameras? Well, she is a freelance photographer and journalist who has lived in or near Ottawa for most of her life. Being a Canadian citizen, she is traveling on the Healy as an observer, essentially being the public’s eye. But she’s been almost everywhere. Lee has given photography classes in Australia, Nunavut, and Chile, and she has raced sled dogs. She also is head coach of a rowing club. Lee has seen a lot, and because of her skills, knowledge, and artistic ability with both camera and pen, others can see and read about the places she’s been. Lee learned the “ART” of photography by trial and error, starting her photographic career working for a newspaper. She had access to a lot of film there, and honed her skills by doing. She has a very keen eye, and her attention to detail is amazing. She contributes regularly to “Above & Beyond”, Canada’s Arctic Journal which is published every 2 months. Her photographs have appeared 3 times on the cover of “Above & Beyond” over the last 3 years. So, when she’s around on the deck with camera in hand, she attracts a lot of attention. Either to see the world the way she sees it, watch her “do her magic”, or to get insightfull comments from her on how to take better pictures. PLUS, the stories she can tell about her other shoots makes you envious of the things she’s experienced and captured on film. Two days ago, while heading towards Pond Inlet, we experienced very light winds. The warm air over the cold ocean again produced fog, but the sun was trying to peek through. I was on the flight deck with Lee, taking some pictures of the scientists preparing to test the horizontal ranging of the acoustic releases, when there appeared a “fog-bow”, as Lee called it. (See fig 1) In principle, it is the same as a rainbow, but the color is washed out since the size of the drops of water are much smaller in fog. Clouds and fog are composed of tiny water droplets, that are not heavy enough to fall as precipitation. (If you’ve ever been driving in a car through fog with your hand out of the window, your hand will become wet.) So I’ll illustrate how rainbows are formed, and the principle is the same for the smaller water droplet found in fog. A typical fog drop size is 5 microns, whereas the smallest rain drop is on the order of 500 microns. So a minimum size difference of 100 times or more. Since fog is at least 2 orders of magnitude smaller, the refraction of light doesn’t occur to the same degree as in a raindrop. So the dispersion of light into the colors of the rainbow is washed out. Here’s how a rainbow is formed: Sunlight strikes a water droplet and refracts while it passes into the droplet. Refraction is just the bending of waves due to a change in velocity. Since light travels slower in water than in air, the light ray bends downward (in a direction more towards the normal to the surface) and travels through the drop to the other side. This ray then reflects off the back surface of the drop and comes back out of the front of the drop. However, since the light ray will now be traveling faster in air, the ray bends the other way (in a direction away from the normal to the surface.) The different colors of the rainbow are due to the changing speeds of the different wavelengths of light. Red light is bent the least, while violet light is bent the most. From the diagram, it would appear that the rainbow should have violet on top, but for the violet light to reach our eyes, the drop has to be lower in the sky (has to come from drop #2). Hence we all know the ROYGBIV acronym from elementary school days, with red on top and violet on the bottom. Some of Lee’s work can be seen at http://www.above-n-beyond.com. Tomorrow I will continue with optics and talk about cameras and lenses.