Posted on 22nd January 2009 by Judy Breck in general science | physics
collider, factories, hadron, learn, neutrino, node, particls_physics
This learn node about the future of particle physics is a webpage on the Interactions.org Particle Physics News and Resources website. The introduction to the page explains:
The Future
Particle physics has reached an extraordinary moment in the quest to understand the universe and its physical laws. Profound new questions have emerged to capture the human imagination. To address these questions, scientists all over the world are collaborating to imagine, design and build the particle physics of the future.
The page offers links to hadron colliders, linear colliders, neutrino factories and other key places where the where the work is being done to on the particle physics quest. The result is a learn node in an online open cluster that you can explore to learn about particle physics from the scientists and institutions who are participating in this extraordinary moment in the quest they leading.
Posted on 25th July 2008 by Judy Breck in astronomy | general science | physics
apod, astronomy, day, learn, node, picture
Astronomy Picture of the Day (APOD) began on June 16, 1995 with the computer generated image shown here of Earth as a hypothetical neutron star. Each day since, the two astronomers who create APOD have devised a learn node: a webpage that focuses on a small subject interfaced by an image, and that links out into the Internet to related topics. Pushing, as learnodes.com does, for something called “learn nodes” is not an effort to invent something new. A learn node captures content for learning by exploiting the natural powers of the open Internet. The robust, 13-year history of APOD illustrates the validity and educational power of basing learning content in nodes.
Using the network node is the first key to the effectiveness in creating superior knowledge content in the open Internet. The second key is the creation of the nodes by people who are experts in their subject. The About page of APOD explains:
Astronomy Picture of the Day (APOD) is originated, written, coordinated, and edited since 1995 by Robert Nemiroff and Jerry Bonnell. The APOD archive contains the largest collection of annotated astronomical images on the internet.
In real life, Bob and Jerry are two professional astronomers who spend most of their time researching the universe. Bob is a professor at Michigan Technological University in Houghton, Michigan, USA, while Jerry is a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland USA.
Posted on 14th May 2008 by Judy Breck in engineering | mechanics | physics | sciences
buildings, damage, earthquake, frequency, oscillation, resonance, Sichuan

The above image combines a map from the USGS Earthquake Hazards Program with a formula from a Connexions module by Sunil Kumar Singh that teaches forced oscillation. The map was captured as a screenshot from the USGS website 2 days after the Sichuan Earthquake began, and as the large squares on the map indicate, the aftershocks were continuing.
The Connexions module text accompanying the formula explains:
The resonance is an interesting feature of oscillation. This phenomenon attracts interest as it makes possible to achieve extra-ordinary result (material failure of large structure) with small force! Resonance also explains why earthquake causes differentiating result to different structures – most devastating where resonance occurs! The condition for maximum amplitude is obtained by differentiating amplitude function with respect to applied frequency as [the illustrated formula sets out.]
Thomas L. Pratt, who teaches research geophysicists at the University of Washington, provides a webpage that explains frequencies, periods, and resonance in which he includes this simple explanation: “Resonance is when motion at a given frequency is amplified by waves of that same frequency. For example, when a child is being pushed on a swing, the swinging is increased by a push being applied at the right time (at the correct frequency) during each swing.”
At Science Fair Central you can follow instructions for a simple experiment with 2 paper circles and a piece of cardboard to show why earthquakes shake some buildings more than others.
Posted on 8th May 2008 by Judy Breck in math | physics
formulas, gravitation, gravitational, johannes, kepler, laws, motion, newton, physics, planetary, yale

Kepler’s Laws, Newton’s formulas: grasping grand concepts from great teachers is the online luxury of this learn node. Rice University’s Galileo Project provides the Johannes Kepler biography. NASA spins in an overview for science teachers of Kepler’s Three Laws of Planetary Motion. The image with this post is from a Syracuse University Physics applet that animates Kepler’s Laws.
A class video lecture is provided of Ramamurti Shankar, the John Randolph Huffman Professor of Physics and Professor of Applied Physics at Yale. From from a course in the Fundamentals of Physics, the lecture on Kepler’s Laws covers these ideas: “The focus of the lecture is problems of gravitational interaction. The three laws of Kepler are stated and explained. Planetary motion is discussed in general, and how this motion applies to the planets moving around the Sun in particular.”
Posted on 25th January 2008 by Judy Breck in physics | sciences
Chandra, cycle, MIT, neutron, physics, pulser, reactor, star, vela, x-ray
In a learn node here featuring the MIT Open Courseware on Neutron Science and Reactor Physics this chart of the Neutron Life Cycle is found in Lecture 7. The introduction to the lecture explains that:
A major objective of this course is to determine the neutron flux as a function of both position within a reactor core and the neutron energy. Neutron life cycle analysis is the first method that we will examine for this purpose. It was the principal means of design for nuclear reactors in the 1950s, before the advent of significant computational power. It remains an important tool for qualitative understanding and, in some cases, for quantitative analysis of criticality.

Cosmic perspective on neutrons, is found at the Chandra X-Ray Observatory webpages on Neutron Stars/X-ray Binaries. The image is the Vela Pulser.
More learn nodes at: learnodes.com