Tuesday, May 30, 2006
(Hat tip and image source: SciFi.com)
Sunday, May 28, 2006
An alleged British terror cell talked of blowing up London's Ministry of Sound nightclub, the Old Bailey heard today.(Hat tip: Winds of Change)
Jurors were played secret security service recordings in which two members of the alleged cell discussed possible terror targets in the capital and across England.
Jawad Akbar and Omar Khyam, both members of the group - which was allegedly linked to al-Qaida - considered the Ministry of Sound, which can hold up to 1,800 people, to be an easy target.
So, that brings us to the teenagers' exploit - record the Mosquito tones (clever marketing name, that) and use them as ringtones on their mobile phones. Now they are able to get text message and call alerts during class without their teachers hearing them! News article here.
(Hat tip: GeekPress).
Friday, May 26, 2006
US News & World Report has a couple of short pieces (one and two) about possible tampering involving the Zapruder film of the assassination of JFK. Links to scanned images are on the second of the two pages. Comparison of the images allegedly show discrepencies in the color of shoes, which is why I thought this might be of professional interest. Please note that I have not studied these in detail and am not supporting or refuting any allegations.
(Image Source: US News & World Report)
What the video shows are the standing wave patterns produced by exciting an elastic sheet with salt on it using an audio tone generator. The tone generator is then tuned through audible frequencies, pausing at obvious resonant frequencies of the sheet (i.e. frequencies where it produces standing waves determined by the dimensions of the sheet). The salt settles into patterns that help you to visualize the standing waves set up at the resonant frequencies. I read one blog comment by a competent-seeming person that said that the salt settles to the points where the sheet is not displaced at all, but that doesn't sound quite right to me. Maybe I'm missing something, but it seems to me that the salt should settle to the lowest points of the standing wave, which would be a regular pattern of sationary dips. I'll have to give this some more thought (or, even better, just do the experiment in my next lecture on audio). If any of you readers have any additional insight, please post a comment!
This type of demonstration is a classic one used in high school and university physics classes around the world. The study of these patterns can be traced back to Ernst Chladni (a modern founder of the science of acoustics) and his student Hans Jenny, who popularized the study of such patterns in his 1967 book Cymatics (from the Greek word "kyma" meaning "waves"). "Cymatics" is now the recognized term for the study of wave phenomena.
(Hat tip: Digg)
(Image Source: a Chladni figure found in the Wiki entry on Cymatics)
Monday, May 22, 2006
Personal aside: As I've been a Freemason for many years and am also keen on history and religion, I really am amazed at the amount of interest in 'The Da Vinci Code' and 'Angels and Demons'. I hopeful that these bits of pop-fluff entertainment will entice more people of all persuasions into studying more about our past (and judging by the number of books in the local bookshops on all aspects of 'The Code', somebody must be). It is my fervent belief that we have a lot to learn from our ancestors. They were people just like us in their struggles, hopes, and dreams but probably a good bit smarter and wiser since they actually used their senses and brains for analyzing things, both small and large.I originally got onto this topic via this article on PhysOrg but after some digging around trying to find an actual link to the Japan Acoustic Lab webpage (which I didn't ever find) I came across a more comprehensive write-up on the origins of the Da Vinci and Mona Lisa reconstructions. It turns out that the lab was reconstructing various famous voices that are now sold as ringtones for mobile phones.
As far as forensic science goes, I was pleased to see that many of the articles I found on the Internet about the reconstructions did point out that there were a lot of assumptions that had to be made, including Mona Lisa's height for starters as she is sitting down in her portrait.
(Image source: J@pan Inc. website)
It is surprisingly refreshing and addictive. Give it a listen and hear for yourself.
(Hat tip: Daily Telegraph)
(Image source: UCSB Cylinder Preservation and Digitization Project)
Monday, May 08, 2006
With that background, I offer a link to a DIY camera obscura. This is a great project that improves on the original variety by incorporating a modern lens to allow bright AND sharp(er) images at the same time. I'm planning on making one of these with my kids during the summer holidays so they can view the morning sunrise in an interesting way.
(Hat tip: Make)
Monday, May 01, 2006
(Image source: Nikon Small World Gallery)