Babies are Quantized

A blog post which tickled my physics nerd funny bone: babies are quantized.

Re: Units at the Science Museum

I got a response to the letter I wrote the Birmingham science musuem. This is what Jeff Smith, director of IMAX theater operations has to say:

Lamar has just passed your message along about the stats presented in the IMAX Theater Pre-Show. I have to agree with your comments, but have never changed the show since this is the way it was originally produced, but having talked with the creator of the show over the years, I have learned his methodology for the 24,000 CD-ROMs of information statistic.

According to him, if you take the average 74-minute CD-ROM at 650MB of data, and multiply it out, that would result in nearly 15TB of data for the image portion of a film.

Going backwards, assuming a 45 minute film, that would be ~241MB per frame (at 24fps.)

There is actually an active argument in the IMAX industry over the past few years concerning what type of resolution you need to achieve the quality of an IMAX 15/70 film presentation. An IMAX VP has said that it is the equivalent of a 105 megapixel image. While I think this might be a bit overkill, I've seen 8k images output, and that is far too low compared to the image quality of the film.

Hopefully this helps explain our usage of units a little.

In other words, it would take 24,000 CD-ROMS to store a 90 minute IMAX film as a sequence of uncompressed, 105 MB images.

Units at the Science Museum

While in Alabama this past weekend, I visited the Birmingham science museum, called the McWane Science Center. It was a fun diversion for me, especially since the first floor of the museum was essentially all physics toys. Sadly, I discovered some problems with units on a couple of the displays, so I sent this letter to the museum:

I visited your museum this past weekend and really enjoyed your exhibits. I think you have developed a nice set of hands-on exhibits which are both fun and educational.

Being a physicist, there were a couple problems with signs that I wanted to bring your attention.

First of all, on your combustion engine display there is a sign explaining the origin of "horsepower". This sign says that one horsepower is equal to: 33,000 lbs per ft / 1 minute

Unfortunately, lbs / ft / minute is not a unit of power. The correct units are ft. lbs. / minute (distance * force = energy, then energy / time = power). Or to be more explicit about the problem, pounds should be multiplied, and not divided, by feet.

The other thing I noticed was also an issue with units. In the IMAX theater you have an introductory sequence which shows the audience the speakers and screen (this sequence is very cool, by the way). At one point in the sequence a claim is made to the effect of: "resolution of 2,400 CD-ROMs". Last I checked, a CD-ROM was not a unit of resolution. It also does not make sense to refer to the amount of information storable on a CD, as the resolution of such an image depends on the encoding.

Perhaps what you mean is to compare to the resolution of a video CD (which is half the resolution of VHS or DVD video, an odd standard to compare to). In that case, your number also does not make sense.

To properly digitize IMAX film requires scanning the negative with 8,000 horizontal lines of resolution (and a similar number of vertical lines... this is referred to as 8K resolution in the movie industry). A video CD has 240 lines of horizontal resolution. If we are just comparing horizontal lines, then, we have 8000 / 240, or roughly 33. Obviously, this is a far cry from 2,400.

I think of I have gone off far enough in my digression, so I'll stop there.

Thanks for reading.

March Meeting 2006

Every March the American Physical Society hosts a meeting for condensed matter physics. It is a huge event-- this year there are close to 6,000 physicists here. You learn about the goings on in the physics world in rapid-fire 10 minute talks. You might not think that you could learn much in a 10 minute talk, but most groups that are presenting new results have multiple group members giving talks. So after seeing 3-4 talks from the same group, you do feel like you have learned something. Anyway, I'm off to another session soon, so more later...

Cold Fusion Exists!

The Feb 10th issue of Physical Review Letters included a paper by some researchers at Rensselaer which confirmed earlier experiments done at UCLA to achieve nuclear fusion at room temperature using pyroelectric crystals. I've only done a cursory reading of the paper, but it looks like what they do is take two crystals which develop a strong charge on their surface when heated or cooled. They put these crystals in vacuum and heat them a bit which causes a very strong electric field to develop between the crystals. The field drives electrons between the crystals with enough energy to create a fusion reaction. The authors state that this system is probably not useful as an energy source, but they do expect to be able to use the technology to create a hand-held neutron generator.