Category Archives: Physics
That's a Mighty Big Wind Chime You Got There
Aeolus – Acoustic Wind Pavilion
The sculpture a giant aeolian harp, designed to resonate and sing with the wind without any electrical power or amplification. Vibrations in strings attached to some of the tubes are transferred through skins covering the tops, and projected down through the tubes towards the viewer standing beneath the arch.
Find Your Center Redux
Find Your Center
… of mass
Scamming the Tourists
This has nothing to do with the earth rotation and the Coriolis force. It’s purely for the suckers.
Here’s the trick: notice how he pours the water into the basin on each attempt. You don’t see it for the original one; it’s been sitting there for a while and has settled while he does the little demo with the compass and probably some more lecture. But he pours the water off-center for the next two experiments, so there is already some rotation of the water, and the result is exactly the direction you’d expect from the pour. When he pours on the left side of center, it drains clockwise, and when he pours on the right side, it drains counter-clockwise.
One, of course, should do this with both pour techniques in the same location to be a real experiment.
Follow That Law!
Justices Back Mayo Clinic Argument on Patents
In his opinion for the court in the case, Mayo Collaborative Services v. Prometheus Laboratories, No. 10-1150, Justice Breyer started with first principles.
“Einstein could not patent his celebrated law that E = mc2[sic]; nor could Newton have patented the law of gravity,” he wrote.
…
In general, Justice Breyer wrote, an inventor must do more than “recite a law of nature and then add the instruction ‘apply the law.’ ”“Einstein, we assume, could not have patented his famous law by claiming a process consisting of simply telling linear accelerator operators to refer to the law to determine how much energy an amount of mass has produced (or vice versa),” he wrote.
I wonder if some savvy lawyer would interpret the specific mention of linear accelerators to mean that cyclotrons are to be treated differently…
It Doesn't Take a Physicist to Correct a Physics Mistake
An article claimed — in its headline — that a ~5ºC (~10ºF) increase in temperature was an increase of 18.7 percent, by calculating using the relative temperature scale. Which is wrong, of course; e.g. 2ºC does not represent twice as much thermal energy as 1ºC. The site has since made a correction.
If you really want to do a percentage based comparison, you need to convert to an absolute temperature scale like Kelvin, which shows you that it’s actually a 1.8 percent increase in temperature (306.75 / 301.45). This is middle school science.
Sadly, I don’t think that this is generally taught in middle school. Or possibly even high school, except to a few students.
Pet Physicists
SMBC: The life cycle of a physicist
Remember, if we let you get a pet physicist, you have to promise to help keep the lab clean and, most importantly, you have fund him/her every year.
Please Tell Me You Know the Answer
The Ol' Switcheroo
The bit about how the speed of light being constant was established before Einstein was born refers to Maxwell’s equations, according to which electromagnetic radiation has to travel at the same speed in all frames. Physicists eventually realized the light and EM waves were the same thing. This is something that isn’t always stressed in the teaching of the development of relativity, and one might get the impression that the postulate of c being invariant was just a guess.