The transit of Venus is a rare astronomical event that has been well documented throughout history. The most recent transit occurred in June of 2004, and the one before that took place more than 100 years earlier in 1882. This site from the South African Astronomical Observatory provides information and first-hand observations of the 1882 event from Wellington, South Africa. Just prior to the event, an observatory was erected at the Huguenot Seminary for girls, and some of the historical observations made from that site in 1882 are provided here for your perusal.

Created by David Lane of Rice University, this applet simulates experiments using 2 x 2 contingency tables. You specify the population proportions and the sample size and examine the effects on the probability of rejecting the null hypothesis. The author provides instructions and then five different exercises to practice these concepts. Overall, this is a nice interactive resource that allows users a more hands-on approach to statistics.

In 1953, Gottfried Moellenstedt invented the electron biprism, more or less by accident, with the serendipity characteristic to him: Aiming at dark-field imaging in an electron microscope, he stretched a thin tungsten wire across the objective aperture to block off the zero beam. However, instead of a dark field image, because of inadvertent charging of the wire under the beam, he found two images of the ZnO-needles serving as an object. Instead of trying the dark field imaging over and over again, he asked what the effect would be if the obtained two images were superimposed. Is coherence given? Moellenstedt, educated by Walther Kossel in diffraction of electron waves, had a vision: Together with his PhD-student Heinrich Dueker, he developed the electron biprism, consisting of a 1 micron m thin wire deliberately chargeable by means of a voltage source, as a beam splitter for coherent superposition of the electron waves passing the filament on the right and on the left. In 1955 they published the first results showing biprism interference fringes [G. Moellenstedt and H. Dueker, Naturwiss. 42, 41 (1955)], which, since then, gave access to the understanding of electron waves and their use for analysis of object structures up to atomic dimensions. Target Audience: 2-4 Year College Faculty/Administrators

9th Grade Math Practice Questions to test addition, multiplication, word-problem skills, and basic algebraic skills. Includes answers and explanations. From the Proficiency Building Activities of the NASA Lewis Research Center K-12 Program.

Provided by the American Dental Hygienists' Association, this site's resources are valuable for both dental patients and hygienists to help understand "the importance of oral health to total health." Patients will find informative fact sheets describing potential oral health problems as well as tips for preventing them. Hygienists will find the free posters useful as well as the instructions included for proper brushing and flossing techniques in order to educate and support their patients. The site underscores dental hygienists' roles in tobacco cessation efforts, a major topic of concern in the allied health professions. Providing free "life-saving advice", the ADHA hopes to promote overall heath beginning with oral care.

This site, created by Michelle Lacey of Yale University, gives an explanation, a definition and an example of ANOVA for regression. Topics include analysis of variance calculations for simple and multiple regression, and F-statistics. This is a great overview of this topic.

AQUASTAT - a global information system of water and agriculture developed by the Land and Water Development Division of FAO - provides comprehensive information about agricultural water management across the world, with emphasis on developing countries and countries in transition. The site includes a database of country data, country profiles, maps and GIS, water resources, online publications, and links to related sites and resources.

This curriculum guide, from the American Radio Relay League, is "a resource that will help you do what you do best...teach, and teach in a refreshing, captivating way that will bring your students into the world of wireless technology, a journey that will enrich their lives, and our lives." From this site, visitors can either download the basic document or browse the various units and activities listed here. Topics covered include Ohm's Law, Oscillators, Wireless Technology in Robotics, and an Introduction to Ham Radio, among many others.

ATE Central is a freely available online portal and collection of materials and services that highlight the work of the Advanced Technological Education (ATE) projects and centers. These National Science Foundation funded initiatives work with educators from two-year colleges to develop and implement ideas for improving the skills of technicians and the educators who teach them. ATE Central is designed to help educators, students, and the general public to learn about, and use materials from, the entire depth and breadth of the Advanced Technological Education program.ATE Central helps direct users to a full range of high-impact ATE resources available online, including curricula, learning objects, and podcasts. The portal aggregates information about the materials developed by ATE centers and projects, and organizes them using subject taxonomies, context appropriate keywords, and other digital cataloging techniques.

This video, created by ATETV and presented by WGBH, takes a look at internships and co-ops that students can participate in while earning their degree. This video explains the value of participating in internships and co-ops to gain valuable workplace experience to show employers after graduation. The hands-on skills that students learn will be complemented by classroom work, creating graduates proficient in both experience and education. This video is helpful for students whose skills and education could benefit from internships or co-ops. Educators will also find a background essay, discussion questions, and standards alignment for the material. Running time for the video is 2:09.

This Gulf of Maine educational website takes students aboard the submersible Alvin. It includes informational pages such as a project overview, as well as pages about Alvin, hydrothermal vents, and the researchers involved in the project. Classroom activities explore nautical and mythical names such as the Titanic, instruct students how to make a model of the ocean floor in a shoebox, and introduce topics such as deep sea vents and plate tectonics. A photo gallery highlights research aboard the Alvin and links are provided to recent dispatches describing research experiences on the Alvin.

This case study provides an introduction to HIV, including the life cycle of the disease, its treatment, and problems associated with different treatment options. The case would be useful in an upper level high school or lower level undergraduate class studying health and biology. The case study and teaching notes may be downloaded in PDF format. The site also includes a section for instructor feedback where general comments may be read and contributed.

This tutorial is comprised of 10 modules that offer information, instructional techniques, and practice labs on how to make the most common needs in distance education accessible for individuals with disabilities, and enhance the usability of online materials for all students. The modules center around topics such as making video, flash, word , PDF and many other documents accessible for students with disabilities.

This post on the AmericaView Blog describes accessing Landsat data and using it in the ArcGIS program. The post includes a link to an instructional video which will show you how to access freely available Landsat satellite imagery and data and then work with it in ArcGIS. Running time for the video is 8:01.

Pamela Peterson Drake, Professor of Finance at Florida Atlantic University, has prepared this site to ˘ď‹ďĐrefresh a student's accounting knowledge in preparation for further studies in finance.˘ď‹ď Topics on the site include the foundations of accounting, balance sheets, income statements, statements of cash flow, and additional disclosure. Each topic contains a thorough explanation with examples. At the end of the review, there is a quiz for visitors to test their knowledge of accounting basics. This is a useful resource for students in accounting services, and also for educators to incorporate into their classrooms with minimal or no adaptation to the review needed.

This learning activity from the Advanced Technology Environmental and Energy Center (ATEEC) provides students with the opportunity to use analytical meters and instruments and perform acid deposition sampling. Students will collect samples from various sources over a period of time, then measure pH and develop graphs or charts. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Acid precipitation will be defined. At different points in the lesson students will write balanced reactions for the formation acid precipitation from atmospheric sulfur and nitrogen oxides and the neutralization of acids by limestone. Students will determine which states are most at risk from acid precipitation and assess how that risk has changed from 1996 to 2006. Sources of atmospheric sulfur (burning of high-sulfur coal) and nitrogen oxides (automobile exhaust) will be listed. The buffering effect of limestone soils and its mitigating effect on acid precipitation will be discussed. Students will correlate these areas with sulfur and nitrogen oxide production, population, composition of coal fields, and soil composition. This resource includes both a teaching guide and student worksheets.

The Acoustic Monitoring Project at NOAA is observing the ocean through underwater acoustics. At this site, visitors can learn about NOAA's studies in Bioacoustics, Ocean Seismicity, and Environmental Noise. The site also offers many animations dealing with Axial eruption, Atlantic Seismicity, and much more.

About 150 common acronyms in organic chemistry are listed along with their full names and structures.

This resource covers Seyfert galaxies, radio galaxies, BL Lacertae (BL Lac) objects, quasars, supermassive black holes, determining masses in galactic centers using the virial theorem, and a model for active galactic nuclei.