Science and Math: Another round-up of interesting links

I have been having difficulty finding enough time to write my normal analysis and commentary on the information I have come across. Therefore, in order to not fall any further behind in getting interesting things out to you, I'm going to once again resort to listing the links.

With apologies, here they are:

US Judge rules that computerized voice stress analysis can be used to monitor offenders  (note: I've blogged previously about how detecting stress is NOT the same as detecting a lie)

Mathematicians: An Outer View of an Inner World

NASA Interstellar Boundary Explorer Mission

Forensic Audio overview article

Mysterious spiral lights
(solution: failed Russian missile launch)

Victorian Infographics

Virtual tours you don't want to miss

Saturn at equinox

The secret life of chaos

Enjoy!

Acoustics: Shattering glass with sound

I really enjoy Make Magazine (USA) for their many contributions to open source hardware development, but that is not the subject of this post. Instead, I'd like to point you to an excellent video they have up on their site from the MIT Department of Physics on breaking a wine glass with sound.

Audio Forensics: Signal Processing helps unravel JFK Shooting evidence

IEEE (The Institute of Electrical and Electronic Engineers) has started a public video section on its web site it calls ieee.tv.  I have been a member of IEEE since at least my graduate school days, as are many speech and forensic scientists, so if you are in either one or both of these fields and are not a member, I highly recommend that you check into it. (And in the spirit of full disclosure and in the hopes of avoiding investigation under who knows what new law is actually now or ever will be on the books about such things on the Internet - no, they didn't pay me to plug them as a professional organization!).

On to the subject of this post: ieee.tv has a fascinating video clip on the gunshot analysis performed by various experts on the recordings JFK assassination.

Hat Tip: Thanks Alex!

Physics: A round-up of recent interesting links!

My aplogies for my light posting of late. Outside commitments have kept me from posting nearly as much as I would like. Here is a collection of links that I have saved up over the last several weeks to blog about. I hope you enjoy them, but please note that some of these are not serious, scientific articles - just because it can be found on the Internet doesn't make it science, much less forensic science! If you are particularly interested in any of the topics addressed below, just let me know and I'll delve further in a future posting.

K-Lite codec package update

X-rays made from Scotch(R) tape (hat tip to A.A.)

Superconductivity Can Induce Magnetism

Deaf people feel their way to speech

Seeing Through The Skin: Optic-less Imaging Technology Could Beat Lens-based Imaging Devices

HOWTO read the secret forensic dots in your laser-printer output

Biometric identifcation by body language

Sound-card oscilloscope

Audio bone headphones

Scientists Watch As Listener's Brain Predicts Speaker's Words

Hidden airport scanner will pinpoint terrorists

Overpaid professions

Military camouflage

Police probe cell phones to catch criminals

How magicians control your mind

How forensic lab techniques work

Computers reassemble pieces of fractured archaeology

Review of Microsoft's Photosynth

Images of atmospheric optics

12 worst Photoshop mistakes ever

Darpa super-resolution vision technology R&D

How other senses adjust to blindness

Family name geographical profiler

Fun: Top Ten Amazing Physics Videos

Wired has them. Enjoy!

Acoustics: Acoustic cloaking

First there came visual cloaking of tanks, et al. Now, there is a design idea for an acoustic cloak - I should have seen it coming (pun intended)!

Physics: Physics for Future Presidents

I freely admit that I am a geek. However, strange though it seems to me, I am not a gadget freak. That being said, even I was won over to podcasting. A friend got me excited about listening to university courses on-line via podcasts (thanks, Amy!). An iPod Nano and iTunes were my ticket to liberation from over-the-air radio during my travels.

With that small confession and short history out of the way, I got the urge today to share one of my favorite podcast courses with you - Physics for Future Presidents, by Richard Muller. His explanation of the issues and science around global warming alone is worth the cost of an MP3 player. You don't have to use iTunes to download it, but it is convenient if you do. Enjoy!

Physics: How are sound and light different?

Sound and light are very different, even though they are both waves.  For instance, one can travel in outer space and the other one cannot - at least outside of Hollywood, sound doesn't travel in a vacuum! 

To explain more fully, let's start off with how light and sound are the same.  Both are indeed waves and therefore have amplitudes, frequencies, wavelengths, and speeds.  Wavelength is the distance a wave travels before repeating, or, put another way, it is the distance between two successive troughs or peaks on a periodic (repeating) wave.  Frequency is the number of times a wave repeats in a second and is closely (and inversely) related to wavelength.  The speed of a wave is the frequency times the wavelength.

One way that they differ is in how they propagate. Sound requires a media to travel in because it is basically just a change in pressure.  For example, in air, it is a change in air pressure that carries the sound.  Sound can also be carried by other media, such as water (e.g. sonar).  Light, on the other hand, is an electromagnetic wave, which means that it is a combination of electric and magnetic fields that travel together.  Therefore, it does not need air, water, or any other medium to carry it - in essence, it carries its medium with it.

Another way in which they differ is in their speeds.  Sound travels about a foot (approximately a third of a meter) in a millisecond.  Light, on the other had, travels 186,000 miles (300,000 kilometers) per second.  Talk about the tortoise and the hare!

So, despite many similarities, sound and light differ in ways that are significant and have consequences for many different life forms - but that is a topic for another posting.