He incorrectly claims that a cyclist can get more torque by having a crank arm that’s “longer” but bends back towards the center, keeping the pedals the same distance away from the axis as a traditional straight crank. Levers don’t work like that. It doesn’t matter what shape the lever arm is, it only matters how far away the pedal is from the center of rotation.
Good to note that the Kickstarter attempt failed miserably, not so good that there’s a smaller-scale attempt elsewhere.
An Innovative and Cheap ‘Solar Bottle Bulb’ Solution Lights Homes in Manila
This is a really neat solution to the problem of dwellings that could really use passive light; it’s not truly an alternative to something like the gravitylight , which is not passive, but for closely-spaced dwellings that don’t have much in the way of window real estate relative to the interior area, and lack (affordable) electricity, it’s just the ticket to light them up during the day.
This is a kind of light pipe (one version of which is a deck prism seen on some boats). I have to think something like this would have been useful for a playhouse when I was a kid. Some more detailed instructions exist, if you are inclined to employ on of these.
Here’s a couple of posts on the negative-temperature experiment that was in the news last week:
Uncertain Principles: What Does “Negative Temperature” Mean, Anyway?
Built on Facts: Less Than Absolute Zero
The upshot of all this is that many of the stories were generally over-hyping the negative temperature aspect of the experiment, some to the point of simply getting it wrong that somehow this was a new and earth-shattering result. A spin system was put into a negative temperature state way back in the early 1950’s, and (as Matt points out) lasers have population inversions in them as well. One should note that you don’t get these negative temperatures via straightforward thermodynamic means — you have to rig the system to do so, meaning they don’t happen spontaneously.
Happy perihelion to all.
Top Physics Breakthroughs of the 13th Baktun
We’re at that time of year where people publish lists of top stories of the year, but as many crazy people will be happy to remind you, this Friday marks the end of another calendrical period, in the Mayan calendar.
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[H]ere are the Top Ten Physics Breakthroughs of Baktun 13
Dot Physics: How Much Does It Cost to Power Your Christmas Lights?
Rhett also analyzes the Griswold house’s consumption from Christmas Vacation, with its over-exaggerated decoration and also set in an era when the tree lighting was less efficient.
Snapping an atom’s shadow? Now that’s a first
The picture leading this article shows the shadow cast in a laser beam by a single Ytterbium atom suspended in empty space. At Griffith University, we have has pioneered the use of Fresnel lenses (a type of lens for large aperture and short focal length – producing an ultra hi-res miscroscope) to capture high-resolution images of atoms.
Physics World reveals its top 10 breakthroughs for 2012
“Mass appeal” pun ahoy!