Posted on 20th May 2008 by Judy Breck in astronomy | engineering | general science | sciences
lander, landing, mars, mission, phoenix, surface
Phoenix Mars Lander is the topic of a magnificent learn node in the New York Science times today. Like any quality learn node, this one in the Times focuses on a small hunk of a subject: the scheduled landing of the vehicle this week on Mars. The node has internal links to superb supporting materials such as the graphic from which a piece is shown at the top of this post – although the graphic regretfully does not have a url of its own. Other internal links do, such as the slide show.
The node aspects are stunted here because there are not links beyond the NY Times to related material, such as The University of Arizona’’s Phoenix Mars Mission home webpage and NASA’s Phoenix Mars Lander homepage. The great news is that the New York Times no longer posts its science materials for free and then a few days later closes them behind a paid subscription. Since it will remain open online, this Phoenix Mars Lander node will remain available to link into other networks of space exploration and related subjects.
Posted on 23rd April 2008 by Judy Breck in biology | brain | general science
auditory, balance, brain, hearing, neural
To begin to learn how hearing and balance work a good introduction is an online overview from the American Speech-Language-Hearing Association. The overview begins:
Hearing is one of the five senses. It is a complex process of picking up sound and attaching meaning to it. The human ear is fully developed at birth and responds to sounds that are very faint as well as sounds that are very loud. Even in utero, infants respond to sound. The ability to hear is critical to the attachment of meaning to the world around us.
The ASHA webpage then explains the functions of the five sections of the hearing mechanism: 1. Outer ear, 2. Middle ear, 3. Inner ear, 4. Acoustic nerve, and 5. Brain’ s auditory processing centers.
Much more about hearing can be learned in the Open University’s Science and Nature materials about Hearing. The illustration with this learn node is from those Open University materials in the section about neural processing of auditory information. To get into even more minute details, the Proceedings of the National Academy of Sciences of the United States have an in-depth article on how visual speech speeds up the neural processing of auditory speech. Together these resources, and the links they in turn provide, are a starting learn node for many related hearing subjects.
Posted on 5th March 2008 by Judy Breck in chemistry | engineering | general science | sciences
learn, materials, metallurgy, NIST, science, solder, soldering, tutorial
The triangle of information shown in this learn node is a phase diagram thermodynamic calculation for solder Bi-Pb-Sn. So who care about something like that? In the advancing complexity of metallurgy, depth of detail is important. This is the explanation of the NIST host of the diagram, whose Web site explains the mission:
The NIST Metallurgy Division is working closely with materials suppliers and users to develop the measurement and standards infrastructure needed in diverse technological areas – from steelmaking to the fabrication of nanostructured multilayers for magnetic recording heads. . . .
Learning about solder might seem more likely to involve technique, like that offered in the PDF which contains the illustration of “Tinning the soldering iron” from About Soldering—making Clip Leads—CLK from MIT’s Open Courseware. A sample of third sort of soldering knowledge available online is this popular Soldering Guide, a tutorial supported by Google ads.
Within the open Internet, patterns of related ideas for the subject of solder can be an amalgam from diverse sources.
More learn nodes at: learnodes.com
Posted on 23rd February 2008 by Judy Breck in astronomy | general science
discover, galaxy, galileo, map, milky, milky_way, survey, way
This learn node focus: To keep up with what is known about our home in the cosmos, the Milky Way Galaxy, online knowledge clusters provide authoritative, up-to-date information and images. The images above are from Sloan Digital Survey, and collaboration of cluster of over 150 scientists and 25 institutions. A December 2007 SDSS news release describes the discovery that The Milky Way has a double halo, as illustrated in the drawing on the left side above. The image on the right of the theoretical model galaxy is from a January 2008 announcement of continuing SDSS surveys studying dark energy, the Milky Way galaxy and giant planets.
There are many excellent Milky Way nodes of knowledge in the open Internet. Galaxy Map, a Web site that is the work of a single expert, has a node on Our Home Galaxy with rich details. Astronomy Picture of the Day has many Milky Way images, including, for example, on on The Milky Way Near the Southern Cross.
And how do we know we live in something called a galaxy and where did our home get its name? Rice University’s Galileo Project explains:
Galileo thought that what had previously been seen as a milky luster in the sky was no more than than these invisible stars. The Milky Way then was just the view of these far distant stars from earth. Nebulae or nebulous stars were in fact actually a number of small stars clustered together. Galileo went on to prove this assertion by sketching out two “nebulae” which were indeed clusters of stars.
More learn nodes at: learnodes.com
Posted on 28th September 2007 by Judy Breck in general science | sciences
astronomy, orbit, satellite, space, sputnik
This learn node notes the fiftieth anniversary of satellites. On October 4, 1957, the Soviet Union launched a 23-inch diameter satellite. It was the first object ever launched into Earth orbit by humankind, as a post I wrote for iCommons.org describes in a birthday salute to this object named Sputnik 1.
Although the image above suggests Sputnik satellite in orbit, it is more general. It is from a Connexions tutorial � an open educational resource where you can learn how artificial satellites are the backbone of modern communications system. A lot has happened in the past 50 years as orbiting objects have diversified and become common. The open learning website How Stuff Works’ section on How Satellites Work begins:
Not so long ago, satellites were exotic, top-secret devices. They were used primarily in a military capacity, for activities such as navigation and espionage. Now they are an essential part of our daily lives. We see and recognize their use in weather reports, television transmission by DIRECTV and the DISH Network, and everyday telephone calls. In many other instances, satellites play a background role that escapes our notice.
An interesting place to move out into the online clusters of the adventures and ramifications of the Sputniks is from this Astronomy Picture of the Day salute to Traveling Companion (which is what “sputnik” means). You can even meet Laika, the first dog in space.
More learn nodes at: learnodes.com
Posted on 1st September 2007 by Judy Breck in chemistry | engineering | general science
chemistry, materials, mixture, science, solution
The sketch in this learn node is from a course taught at MIT. You can virtually sit in on the lectures from the course by clicking this link: Fundamental Concepts of Material Science. The above sketch is from page 7 of lecture L2 PDF that you can download from the list you will get when you click the link. The sketch teaches us:
Mixture: Inhomogeneous multi-phase system where the components are not mixed on a molecular level.
Solution: Homogeneous system, components are mixed on a molecular level.
The difference between a solution and a mixture is a basic idea that the illustration above gives us � so that we can go on in our own learning to other concepts linked to the subject. The PDF of the lecture is an excellent place to move on in this learning; it has 13 pages of basics. The elemental new power of learning in the network ecology online is a matter of grasping a node like this one about “mixture or solution” and linking to related nodes to build concepts and experience thinking.
MORE LEARN NODES about mixtures and solutions from Rice University: “The word mixture can be defined as a heterogeneous association of substances that cannot be represented by a single chemical formula. This definition does not limit mixtures to solids mixed with liquids, nor is every mixture considered to be a solution. . . .”
More learn nodes at: learnodes.com
