Night Vision - The Red Myth Unaided night vision even now in the 21st century is still the subject of some controversy. For those just looking for an executive answer as to what supplemental lighting should be used to reduced the recovery time back to night vision (dark adapted or scotopic) here it is: a fully dimmable white light! This of course is a very incomplete answer but so are the answers red or blue-green and you should know why. Lets start with red, specifically what I will call the red light myth. I believe the myth started in the photographic darkroom. Until about 1906 most photosensitive material (plate, film, and paper) was not very sensitive to red. As more research about the eye was done it was found that the structure responsible for very low light vision, the rods, were also not very sensitive to red. It was assumed then that like film you could use red light, which is seen by the red sensitive cones (there are also blue and green sensitive cones to give color vision), without affecting the rods.
August 4th: Red Light and Night Vision « « August 3rd: A Friends' Salute to the Blue Collar Scientist, Jeff Medkeff | August 5th: The Soul of Astronomy » » Posted by kortney.hogan on Aug 4, 2010 in Podcast | 0 comments Date: August 4, 2010 Title: Red Light and Night Vision Podcaster: Alice Enevoldsen Organization: Pacific Science Center, Seattle, WA: pacificsciencecenter.org Alice’s AstroInfo: alicesastroinfo.com Description: In today’s podcast Alice answers a phone call and broaches the complex relationship between red light, night vision, and stargazing. Bio: Alice Enevoldsen is currently the planetarium supervisor at Pacific Science Center in Seattle, Washington, and volunteers as one of NASA’s Solar System Ambassadors. Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. Transcript: Hello, this is Alice? Oh yeah, that’s a great question! Here’s a short summary to the best of my knowledge about which lights you should use while trying to preserve your night vision: So what were the results?
Co-op America: Real Money: Greening School Fundraisers Greening School Fundraisers If your school or community group needs to raise some cash, think about selling eco-friendly goods from the greenest businesses. For several years, the Parent-Teacher Organization (PTO) at the Charles E. Smith Jewish Day School in Rockville, MD, had held an annual fundraiser selling Sally Foster gift wrap to raise money for the sixth-grade field trip. “This particular group of friends called themselves ‘the Treehuggers,’” says Miriam Glaser, who teaches sixth grade science at the school. As a result of the boycott, the PTO saw a significant reduction in the amount of money they earned, and it didn’t take them long to agree to meet the Treehuggers to discuss sustainable fundraiser alternatives. Though it was too late to stop the Sally Foster sale, the Treehuggers decided to conduct a sale of their own, to raise money for compost bins and recycled paper for the school. “I was very excited about how much we raised,” says Glaser. AAh Haa! —Tracy Fernandez Rysavy
Steiner Lecture: The Human Heart We have often explained how the development of man takes place during the first periods of life, and it is many years since I first indicated how the child behaves to a great extent as an imitative being during the period up to the change of teeth. More or less instinctively — and intensively — he experiences all that is going on in his environment. Later on it is only in the sense organs that the processes of the outer world are thus intensively experienced, although we are not conscious of this fact. In our eyes, for example, we have a process imitating in a certain sense what is going on in the outer world — reproducing it, just as the camera reproduces whatever is there in front of the lens. The human being becomes aware of what is thus imitatively reproduced in his eyes, and thus he gains information about the external world. It is the same with the other senses. So far I have been describing quite simply, from an external viewpoint, how a child grows into the world.
Free Tools Challenge #23: Go wild with Wikispaces This is the 23rd post in the “30 days to using the best of the web’s free tools for educators” series. Be sure to subscribe to the Teacher Challenge blog by RSS, like us on facebook, and follow us on twitter to keep up with future challenge posts as they are published. This guest post was written by Elizabeth Christophy. Objective: In this activity you will: Introduced to what is a wikiExplore ways to use Wikispaces in your classroomBegin your own WikiPlan a way for students to contribute to the Wiki. Overview: When people hear the term “wiki”, their immediate thought is Wikipedia and its sometimes dubious content. Wiki comes from the Hawaiian word for “quick” and a wiki is a website that can be modified quickly and easily. Using Wikispaces, the control of the website is kept in the teacher’s hands. I usually use a protected wiki – anyone can see the pages, but only my students and I can edit them. Getting Started 1. 2. 3. 4. 5. 6. Editing your Wiki Changing your theme Adding New Pages Challenge