Tag Archives: webcasts

Lenz’s Law in Action: Eddy Current Tubes

Eddy Current Tubes — Drop the Magnets down the tube. An eddy current is set up in a conductor in response to a changing magnetic field. Lenz’s law predicts that the current moves in such a way as to create a magnetic field opposing the change; to do this in a conductor, electrons swirl in a plane perpendicular to the changing magnetic field.

Because the magnetic fields of the eddy currents oppose the magnetic field of the falling magnet; there is attraction between the two fields. Energy is converted into heat. This principle is used in damping the oscillation of the lever arm of mechanical balances.

Related: Home Experiments: Quantum Erasingposts on physicsMIT Physics Lecture: Electromagnetism (Faraday’s Law & Lenz Law)10 Most Beautiful Physics Experiments

Bacteria Communicate Using a Chemical Language

Each person has about 1 trillion human cells and about 10 trillion bacterial cells. In the webcast Bonnie Bassler, Department of Molecular Biology at Princeton University, discusses the chemical language that lets bacteria coordinate defense and mount attacks (quorum sensing). The find has stunning implications for medicine, industry — and our understanding of ourselves.

Bacteria do all sorts of amazing things for us: educating your immune system to keep bad microbes out, they digest our food, they make our vitamins…

Related: Disrupting Bacteria CommunicationTracking the Ecosystem Within UsBeneficial Bacteria

E.O. Wilson: Lord of the Ants

This is a great webcast on E.O Wilson‘s career studying ants and animal behavior from NOVA.

Not only is the scientific knowledge very interesting it again shows that challenging conventional wisdom, while part of the scientific method, does not mean it is an easy process for those pioneers. From his web site:

In 1971 Wilson published his second major synthesis, The Insect Societies, which formulated the existing knowledge of the behavior of ants, social bees, social wasps, and termites, on a foundation of population biology. In it he introduced the concept of a new discipline of sociobiology, the systematic study of the biological basis of social behavior in all kinds of organisms. In 1975 he published Sociobiology: The New Synthesis, which extended the subject to vertebrates and united it more closely to evolutionary biology. The foundational discoveries of sociobiology are generally recognized to be the analysis of animal communication and division of labor, in which Wilson played a principal role, and the genetic theory of the origin of social behavior, which he helped to promote and apply in his 1971 and 1975 syntheses. Sociobiology: The New Synthesis was later ranked in a poll of the officers and fellows of the international Animal Behaviour Society as the most important book on animal behavior of all time, and is regarded today as the founding text of sociobiology and its offshoot, evolutionary psychology.

Related: Journey to the Ants: A Story of Scientific Exploration
by Bert Hölldobler and Edward O. Wilson – Huge Ant NestSymbiotic relationship between ants and bacteriaRoyal Ant Genesposts on antsEncyclopedia of Life

Very Cool Wearable Computing Gadget from MIT

Pattie Maes presentation at TED shows a very cool prototype for wearable, useful computing spearheaded by Pranav Mistry (who received a standing ovation at TED). It’s a wearable device with a projector that paves the way for profound interaction with our environment.

The prototype of the system cost only $350. The software, created by them, obviously is the key, but how amazing is that, $350 for the hardware used in the prototype! There is a useful web site on the Sixth Sense project.

The SixthSense prototype is comprised of a pocket projector, a mirror and a camera. The hardware components are coupled in a pendant like mobile wearable device. Both the projector and the camera are connected to the mobile computing device in the user’s pocket. The projector projects visual information enabling surfaces, walls and physical objects around us to be used as interfaces; while the camera recognizes and tracks user’s hand gestures and physical objects using computer-vision based techniques.

The software program processes the video stream data captured by the camera and tracks the locations of the colored markers (visual tracking fiducials) at the tip of the user’s fingers using simple computer-vision techniques. The movements and arrangements of these fiducials are interpreted into gestures that act as interaction instructions for the projected application interfaces. The maximum number of tracked fingers is only constrained by the number of unique fiducials, thus SixthSense also supports multi-touch and multi-user interaction.

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Eric Schmidt on Google, Education and Economics


Eric Schmidt, March 6th, 2009 interview by Charlie Rose:

  • “From our perspective, I think the YouTube acquisition and the Doubleclick acquisition, which are the two large acquisitions we did last year, and the year before, have been phenomenally successful.”
  • He also mentioned the idea of teachers today creating online hubs of information on educational areas, as well as lesson plans. See our Education Resources for Science and Engineering
  • And Flu Trends
  • “We needed the stimulus package, because the stimulus package had, among other things, $20 billion for science and education funding… Real wealth is created by businesses, not by financial engineering, and by businesses that provide new products that solve new problems.”
  • Why do you assume the best students in the world are going to come to America? “Because they choose to come here right now… That is a brilliant [actually not brilliant at all] strategy take the best people hire them in American universities and then kick them out” It happens. “Its shocking.” It happens. “I know we are fighting against it.” “We America remain, by far the place of choice for education, particularly higher education.
  • Technologists as a group tend to be more analytical, more data driven, more personally liberal (more willing to tolerate the differences among people, more global in their focus… [technologists] as a group believe you can literally change the world from technology.”

Related: Eric Schmidt on Management at GoogleEric Schmidt Podcast on Google Innovation and EntrepreneurshipLarry Page and Sergey Brin InterviewMarissa Mayer Webcast on Google InnovationLarry Page on How to Change the World

Darwin’s Jellyfishes

Darwin’s Jellyfishes

Palau’s marine-lake jellyfish actually diverged very quickly from their common ancestor, the spotted jellyfish. Like other jellyfish, the spotted jellies are cnidarians, a scientific grouping that includes reef-building corals. The spotted jellyfish drift in Palau’s lagoon, zapping the occasional zooplankton with their stinging nettles and absorbing the sugary by-products of photosynthesizing algae living in their tissues.

Like many jelly species, the spotted jellyfish has a multi-stage life cycle. Adult males and females with the familiar bell-shaped bodies are called medusae, but you would not recognize very young jellyfish as jellyfish at all. After medusae release eggs and sperm into the water, fertilized eggs hatch as larvae that drift for a few days before attaching to solid objects, such as rocks. The larvae morph into polyps resembling tiny anemones. Polyps can bud off into more polyps or, when conditions are right, into new young medusae.

the jellyfish do not “eat” algae. Like their lagoon ancestors, the jellyfish simply absorb their algae’s photosynthetic leftovers. The jellies get about three-fourths of their energy from algal excretions and the remainder from prey. In essence, the jellyfish are landlords that hunt a bit on the side.

The jellyfish-algae partnership did not originate in the lakes, either. Ancestral spotted jellyfish brought the arrangement with them. “Spotted jellyfish in the lagoon have basic behaviors that help ‘sun’ their algae,” Martin explains. “They move eastward in the morning. The lake jellies have adapted this migration to each individual lake. The most spectacular migration is in Jellyfish Lake.”

The jellies’ migration delicately balances time in the sun (to benefit their algae) and predator avoidance. The gelatinous masses of peanut-shaped Jellyfish Lake begin their day in the western basin. As the sun rises they pulsate eastward toward the rising sun—but not too far east, because the lakeshore is covered with jellyfish-eating anemones. The jellies stop swimming east when they hit the shade cast by mangrove trees lining the shore.

At nightfall the jellies switch to a vertical migration. Jellyfish Lake reaches depths of 100 feet, but only the top 45 feet contain oxygen. The bottom is a toxic vat of hydrogen sulfide. Bacteria do a brisk business at the interface, metabolizing both the oxygen above and hydrogen sulfide below. Every night the jellies bob up and down from the surface to the bacterial layer. Besides helping the jellyfish stay in place, dipping down treats the jellies’ algae to a midnight snack of nutrients excreted by the microbial masses.

Very Cool.

Related: Leafhopper Feeding a GeckoMutualism, Inter-species CooperationCurious Platypus Genome is No SurpriseMalaysian Shrew Survives on Beer

Cell Culture Lab Tour

Joanne Loves Science includes many webcasts on science, take a look for yourself. She contacted me through the post ideas page. She teaches mammalian cell culture techniques and the concepts of stem cells and tissue engineering in the Bioengineering Department at the University of Illinois. In this webcast she provides a tour of the cell culture lab.

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