The purpose of this document is to briefly describe the most common non-electronic calculating devices within an historical context, and to create a source of reference to other pages in the Internet related with this topic. The journey starts 2500 years ago with the Abacus, and ends 30 years ago with the introduction of the first electronic calculators. In order to facilitate the download, the document has been split into three parts: Part I, describes the evolution of the calculating devices up to the invention of the Stepped Wheel by Leibniz. Part II, discusses the main events during the 19th Century, and Part III reviews the development of office machines until the 1960's when the first electronic calculators appeared in the market. {keywords: math, technology}

Selected photographs with descriptions from the book of the same name created by Edward Emerson Barnard and printed in 1927. Only 700 copies of the text were printed at the time and distributed mainly to scientific libraries. This website makes the photographs available to the public courtesy of The Carnegie Institute of Washington.

The back of the envelope is fundamentally about scale. If details were always crucial, if everything was always a close call, everything about the same size, lots of explanations similarly plausible, then there would be no back of the envelope. Its approximation and estimation would not work. But instead the universe has a broad breadth of scale. There is both the very big, and the very small. Often along side each other, providing contrasts so dramatic, that blurring the pieces doesn't change the picture. Explanations, seemingly plausible, that a moment's rough reflection reveals are not even close to fitting. The rough is often sufficient, and should always be the prelude to worrying about detail.

Albert Einstein is back to earth to explain in an easy and humoristic manner his special theory of relativity. Interactive animations allow the user to assimilate the concepts underlying this theory. View the animation (six minutes).

We are the Formal Education Group of the Space Telescope Science Institute's Office of Public Outreach. We promote the science and majestic beauty of the universe for use in the classroom. The materials we develop for educators and learners of all ages are accurate, classroom-friendly, visually appealing, and carefully crafted to adhere to accepted educational standards. By producing and sharing classroom resources based on the Hubble Space Telescope's greatest discoveries, it is our sincere hope that young people will enjoy learning about the universe we inhabit... and perhaps pursue an even greater understanding of it in the future.

An Introduction to Genomics: The Human Genome and Beyond: What is genomics? Find out about the subject, its applications, and how it works with DNA. How Sequencing is Done: Learn about the steps in JGI's process of whole-genome shotgun sequencing. A Historical Timeline: Cracking the Code of Life: The history of genomics, from Darwin to the completion of the Human Genome Project. Genomics Poster: Get your own copy of JGI's poster, which explains genomics and its history. Created by the US Department of Energy Joint Genome Institute.

By Dr. Richard Bader, Professor of Chemistry, McMaster University. The beginning student of chemistry must have a knowledge of the theory which forms the basis for our understanding of chemistry and he must acquire this knowledge before he has the mathematical background required for a rigorous course of study in quantum mechanics. The present approach is designed to meet this need by stressing the physical or observable aspects of the theory through an extensive use of the electronic charge density.

In this semester of Astronomy we shall concern ourselves primarily with the Solar System. As an introduction to that, we shall consider the historical development of our modern picture of the Solar System. This is essentially an online textbook for the class.

In our first semester of astronomy we were concerned primarily with our own Solar System. In this semester we broaden our perspective and consider the entire Universe. Much of the material for this semester is already on the Web at the Violence in the Cosmos site, but it is arranged in a different order than it will be when the following sequence is completed.

The essential concepts in astronomy the science and the hobby -- from Sky and Telescope magazine. Your First Steps in Astronomy. Astronomy doesn't deserve its reputation as a tough, expensive hobby. You just need to start with the right advice. This site covers Words Ya Gotta Know, Names of the Stars, The Stellar Magnitude System, Understanding Celestial Coordinates, The Spectral Types of Stars, An Introduction to Deep-Sky Objects, Names of Deep-Sky Objects, Time and the Amateur Astronomer

Light playing on water drops, dust or ice crystals in the atmosphere produces a host of visual spectacles - rainbows, halos, glories, coronas and many more. Some can be seen almost every day or so, some are once in a lifetime sights. Find out where to see them and how they form. Then seek and enjoy them outdoors.

This site based on the book Atomic Bombing: How to Protect Yourself, published in 1950, details what is likely to occur in the event of an atomic bombing. It covers the destruction from the bomb, various types of bombing scenarios, and the aftereffects of the bombing.

As much fun as the movies are to review and the news is to analyze, it's the everyday misconceptions that to me are the heart and soul of Bad Astronomy. We learn a lot from school and our parents, but a lot of what fills our brain is "common knowledge", things we seem to accumulate out of thin air. Everyone knows that you can stand an egg on end on the first day of spring... or can you? Of course toilets flush the other way in the southern hemisphere... don't they? It's these types of concepts that got these pages started in the first place. A lot of what we "know about astronomy really just isn't right. These pages are my humble attempt to set the record-- and your brain-- straight about the world's real oldest profession.

Almost every culture on Earth includes an ancient flood story. Details vary, but the basic plot is the same: Deluge kills all but a lucky few. Columbia University geologists William Ryan and Walter Pitman wondered what could explain the preponderance of flood legends. Their theory: As the Ice Age ended and glaciers melted, a wall of seawater surged from the Mediterranean into the Black Sea. Maritime explorer Bob Ballard is combing the floor of the Black Sea in search of the remains of ancient dwellings, which would buttress a new theory that a cataclysmic flood struck the region some 7,000 years agoswelling the sea and eventually becoming the basis of the Noah story.

The BBC Science and Nature website contains pages related to BBC television programs as well as featured stories, message boards, quizzes, picture, galleries, games, wallpaper, screensavers, and web postcards.