Saturday, June 24, 2006

Hydrogen Atom Scale Model

"And you thought there was a lot of empty space in the solar system. Well, there's even more nothing inside an atom. A hydrogen atom is only about a ten millionth of a millimeter in diameter, but the proton in the middle is a hundred thousand times smaller, and the electron whizzing around the outside is a thousand times smaller than THAT. The rest of the atom is empty. I tried to picture it, and I couldn't. So I put together this page - and I still can't picture it.

The page is scaled so that the smallest thing on it, the electron, is one pixel. That makes the proton, this big ball right next to us, a thousand pixels across, and the distance between them is... yep, fifty million pixels (not a hundred million, because we're only showing the radius of the atom. ie: from the middle to the edge). If your monitor displays 72 pixels to the inch, then that works out to eleven miles - making this possibly the biggest page you've ever seen."


Friday, May 26, 2006

Physics NewsUpdate - May 26, 2006. The Misshapen Solar System and Counting Terahertz Photons

The American Institute of Physics Bulletin of Physics News
Number 778 May 26, 2006 by Phillip F. Schewe, Ben Stein,
and Davide Castelvecchi

THE MISSHAPEN SOLAR SYSTEM. Having traveled far beyond the planets
in their 28.5-year journey, the two Voyager spacecraft are providing
new information on the heliosphere, the teardrop-shaped bubble that
separates the solar system from interstellar space. At this week's
Joint Assembly Meeting in Baltimore of the American Geophysical
Union (AGU) and several other geophysics-related societies, Ed Stone
of Caltech reported that the heliosphere is deformed, according to
Voyager observations, with the teardrop's rounded edge bulging at
the top (the northern hemisphere of the solar system) and squashed
at the bottom (the southern hemisphere). (See pictures and movies at
) As Rob Decker of Johns Hopkins University Applied Physics
Laboratory explained, the asymmetry is due to a magnetic field from
interstellar space pushing on the southern hemisphere. The field is
about 1/100,000 the strength of Earth's field but its effects can be
felt for billions of miles, since it is acting over a large area on
the very dilute gas at the solar system's edge.
The interstellar field even squashes an important spherical zone
inside the heliosphere, called the termination shock. Analogous to
the circle that forms when water splatters on a sink, the
termination shock represents the boundary at which the rapidly
traveling solar wind (the stream of charged gas from the sun) slows
down abruptly and piles up. Voyager 2's measurements indicate that
the southern part of the termination sphere might be a billion miles
closer to the sun than the northern part. Moreover, forces from the
solar wind cause the termination shock to breathe in and out roughly
every dozen years. Voyager 1 has already ventured beyond the
termination shock, to the heliosheath, the region where solar wind
and interstellar gas mix. So in a way, the end of the solar system
is not clearly defined. Stone guesses it could be another 10 years
(3-4 billion miles) before the two spacecraft pass through the
heliopause (the very outermost boundary of the heliosphere) and
enter purely interstellar space. The spacecraft have about another
15 years of power left in them. (Session SH02 at meeting; see

COUNTING TERAHERTZ PHOTONS. Scientists at the University of Tokyo
and the Japan Science and Technology Corporation have been able to
detect single photons in the terahertz region of the electromagnetic
spectrum for the first time. Previously, such photons, with
energies around 4 milli-electron-volts, could not be seen singly.
THz radiation, essentially in the far-infrared, is a potentially
important telecommunications carrier. Not only detection but
microscopy at ultra-low THz light levels can be performed. By
scanning a quantum-dot probe (highly sensitive to THz light) across
the face of a sample, the sample can be imaged with a
spatial resolution of 50 microns (the radiation itself has a
wavelength of 132 microns). This is even more remarkable when you
consider that the power emitted from the surface being imaged is at
the level of 10^-19 watts (0.1 attowatt). Currently photon-counting
microscopy glimpses a few electrons at a time oscillating at THz
frequencies in semiconductor devices at high magnetic fields.
According to Kenji Ikushima (, the
extraordinarily high-sensitivity of the photon counting approach
will soon facilitate the study of a molecule shaking, rattling and
rolling at THz rates, photon-counting microscopy in this spectral
range will facility the study of a few molecules at a time
oscillating at THz frequencies in semiconductor devices at high
magnetic fields. (Ikushima et al., Applied Physics Letters, 10
April 2006; www.dbs.c.u-tokyo.acjp/~komiyama )

Monday, May 22, 2006

The American Institute of Physics Bulletin of Physics News
Number 777 May 18, 2006 by Phillip F. Schewe, Ben Stein,
and Davide Castelvecchi

EXTREME-ULTRAVIOLET MICROSCOPE PROVIDES RECORD RESOLUTION. At next week's Conference on Lasers and Electro-Optics/Quantum Electronics nd Laser Science Conference meeting in California, Courtney Brewer of Colorado State University ( and her colleagues will present a tabletop optical imaging system that can
reveal details smaller than 38 nanometers (billionths of a meter) in size, a world record for a compact light-based optical microscope. The microscope can keenly inspect nanometer-scale devices designed for electronics and other applications. It will also be capable of catching subtle manufacturing defects in today's ultra-miniaturized computer circuits, where defects just 50 nm in size that were once too small to cause trouble could wreak havoc in the nanometer scales
of today's computer chips. Except for some high-tech details, the microscope works very similarly to a conventional optical
microscope. Light shines through the sample of interest. The transmitted light gets collected by an "objective zone plate," which forms an image on a CCD detector, the same kind of device that records images in a digital camera. However, in the case of the sub-38-nm microscope, there are some advanced technological twists. The microscope uses a laser that
produces light in the extreme-ultraviolet (EUV) spectrum, whose very small wavelength makes it possible to see a sample's tiny details. The EUV light is created by ablating (boiling away) the surface of a silver or cadmium target material so that the vaporized material forms a plasma (collection of charged particles) that radiates laser light. To focus this light, the researchers avoid standard lenses because they strongly absorb EUV radiation. Instead, the microscope uses "diffractive zone plates," structures containing nanometer-spaced concentric rings that focus the light in the desired fashion.
Other state-of-the-art optical microscopes have achieved resolutions as low as 15 nm, but they required the use of large synchrotrons. This more compact and less expensive system has the potential to become more widely available to researchers and industry. In addition, since the extreme ultraviolet laser produces light pulses with very short duration (4 picoseconds, or trillionths of a second), the researchers believe it may be possible to create picosecond-scale snapshots of important processes in other applications. (Paper CME4,

FRICTION AT A DISTANCE, the friction between close objects that aren't in contact, is poorly understood. Seppe Kuehn and his colleagues at Cornell have set out to change this. First, what does contact mean? Kuehn (607-254-4685, suggests that when two objects are less than about 1 nanometer apart they are said to be in contact. One can think of contact friction as being a sort of micro-velcro process---atomic "hills" in one surface scrape past atomic "valleys" from the other surface. To observe non-contact friction, the friction between two surfaces separated by more than 1 nm, the Cornell researchers use a tiny single-crystal microcantilever less than a millimeter long and only a few thousands
of atoms thick. Brought vertically downwards toward a surface, and set in motion, the cantilever will slow down in proportion to the friction it feels from the surface beneath. Surprisingly, the friction force between the cantilever and sample depends on the chemistry of the sample. By studying this dependence of non-contact friction on the chemistry of the sample the Cornell scientists have made the first direct, mechanical detection of non-contact friction arising from the weak
electric fields caused by motions of molecules in the samples. The samples included various polymer materials. This work is motivated by recent efforts towards single-molecule MRI which require the detection of very small forces, and have been hindered by non-contact friction. (Kuehn, Loring, Marohn, Physical Review Letters, 21 April 2006)

Sunday, May 21, 2006

Latest PhysicsWeb Summaries


Related Resources
Physics News
Physics 101 - Basic Information

Elsewhere on the Web


Quantum gases in 3D (May 17)
Condensed matter physicists have come a step closer to their dream laboratory, with the news that two independent teams have managed to trap bosons and fermions together in a 3D optical lattice. The breakthrough provides a model system in which to study real-life solid-state materials, and may even lead to a better understanding of certain biological systems and traffic flow.

LEDs move into the ultraviolet (May 17)
Physicists in Japan have made a diode that emits light at the shortest wavelength ever. The device, made by Yoshitaka Taniyasu and colleagues at NTT Basic Research Laboratories in Atsugi, is made from aluminium nitride and emits deep in the ultraviolet part of the spectrum at 210 nanometres (Nature 441 325). The work represents an important step towards the development of very low-wavelength light emitters that could find use in a wide variety of applications, including medicine, photolithography and to destroy bacteria in contaminated water.

Magnetic fields go to the maximum (May 18)
What is the maximum possible magnetic field allowed in our universe? According to two theoretical physicists in Russia and Israel, it is 1042 Gauss -- a value that is a billion times smaller than the previous estimate for the upper limit. As well as being of fundamental interest,
the new finding -- if correct -- may rule out theories on "superconductive cosmic strings" and also some accepted mechanisms of producing other hypothetical objects such as magnetic monopoles (Phys. Rev. Lett. 96 180401).

Change of focus for liquid crystals (May 19)
Physicists in the US have created a new type of tuneable liquid-crystal lens, whose focus can be changed by varying the voltage applied to it. The new device is better than traditional liquid-crystal lenses because it only has small astigmatism and does not scatter light. It could be
used for zoom lenses and other microphotonic devices (Appl. Phys. Lett. 88 191116).


Analyze the Data and Draw Conclusions

Related Resources
Great Science Fair Projects
Conduct Your Experiment
Physics 101 - Basic Information

Elsewhere on the Web
Hundreds of Science Fair Projects for Students
Science Fair Central offers ideas for science fair projects and experiments

Once you have your data, you will make any calculations you need for the analysis. It is almost always productive to produce graphs and charts of your data to help you understand and visualize your data.

The analysis leads you to the most important question – does your data support your hypothesis?

Your conclusion is a short statement of your experiments results and how they relate to your hypothesis. Once again, don't worry if your results contradict your hypothesis – a negative result is just as interesting.

Saturday, May 20, 2006

Contact Physics Guide

Like almost all bloggers, I'm a real person. You can contact me via my email. While I can't do your homework for you (you will probably learn more from doing it yourself anyway), I might be able to point you in the right direction. If your question is a really good one, I might be able to make the topic of an article in the near future! If you do need homework help, there are several things you can do:

First of all, have a look around my site. I might have answered your problem already. If not, there are a couple of places you can look:

  1. Your text book - Teachers set these for a reason.
  2. Other Text books - look in the same section of the library as your text, and have a look at the books on either side of it - they are probably on the same topic
Finally, if all that fails you, let me know. If there's homework out there with no answer, then someone had better look into quickly!

I do want to hear from you if there is anything you think I need to know - you might have found a really great web page that I have missed, there might be a piece of news I have not heard yet, or there might be something on my page that you just do not get or (hopefully not) is just plain wrong.

Use the address below to contact me via email. Your email will be read (unless it is mistaken for spam - sorry).

Please note that I cannot answer all of your homework problems. Many examples of typical homework problems are available in my worked problems directory. You might like to check out my FAQ page to see if your question has already been answered.

You can also contact me via:

Instant Messaging

Iwill happily chat via IM on any of the following IM platforms - hint: I respond best to people who observe good basic IM etiquette. (email at these addresses is never checked - please email me at the address below)

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About Joseph Andersen

I am a graduate student in the physics at Harvard University.
My undergraduate degree was obtained from UQ in 1999, during which I was awarded the university medal for outstanding scholarship.
I have worked in laboratories searching for gravitational waves, exploring the physics of matter at ultra low temperatures, I am currently working on Climate Simulations.
I have been involved in the UQ Science in Action Program and the UQ physics student club demonstration team – demonstrating exciting areas of physics to school and university students and the general public. I have shown five year olds how to suck water through a straw quicker than their teachers and “tamed” 3000000V lightning generated by a Tesla Coil. I taught mechanics to premed students and poured liquid nitrogen down the front of my body. I have experience at “physics for the non-physicist” while still being a practicing, published physicist in one of the premier science environments.

My contact details
ph +1 857 234 1285
aim dojojo joe

Monday, May 15, 2006

Physicists Use Soap Bubbles to Study Black Holes

People use them to get cars, dishes and clothes clean. Children blow them for fun. And now, a University of Mississippi physicist thinks soap bubbles can help scientists better understand the properties of black holes.


Tuesday, May 09, 2006

Latest PhysicsWeb Summaries

Latest PhysicsWeb Summaries


Try phySpy - Wiley-VCH's new international physics portal. Featuring THE
search engine for physicists. Based on the principle of neuronal
networks, searches for and filters out just the information
you need." (link:


Physics World

Sleeping giant (May 3)
It is right that the US should increase its investment in particle

Antarctica calling (May 3)
Physicists are playing a valuable role in understanding our last great

Top papers (May 3)
In a special readers' poll Robert P Crease seeks your nominations for
the most interesting paper of all time

Antarctica unravelled (May 3)
After more than a century of polar exploration, recent satellite
measurements are painting an altogether new picture of Antarctica.
Andrew Shepherd explains how physics is helping researchers understand
the critical transformations taking place in the world's largest ice

WMAP data put cosmic inflation to the test (May 3)
Measurements of the polarization of the cosmic microwave background open
up a new window on the universe when it was just 10^-35 s old, explains
Gary Hinshaw

Mobilizing magnetic resonance (May 3)
Nuclear magnetic resonance traditionally requires large magnets that
make the technology immobile and expensive. Boyd Goodson describes how
efforts are being made to develop portable devices that will extend the
reach of this powerful imaging technique.

Sensing the extreme (May 3)
From volcano vents to the surfaces of distant planets, silicon-carbide
sensors are poised to take us into environments where we have never
measured directly before, as Alton Horsfall and Nick Wright explain



Cosmology gets precise (May 3)

The Infinite Cosmos: Questions from the Frontiers of Cosmology Joseph
Silk 2006 Oxford University Press 256pp £18.99/$29.95hb

Plotting the life of Descartes (May 3)

Descartes: The Life of René Descartes and Its Place in His Times A C
Grayling Free Press 2005 352pp £20.00hb

Shelf life: Simon Singh (May 3)
Simon Singh is an author, journalist and TV producer specializing in
science and mathematics


Monday, May 08, 2006

Latest PhysicsWeb Summaries


Veneto Nanotech Launches the 2nd Edition of Nanochallenge Enter your
nanotechnology business plan to Nanochallenge 2006 and you could win the
grand prize of Euro 300,000. The competition seeks commercially viable
business plans for innovative start-ups to produce and commercialize
products and services in the nanotechnology industry. Find out more at



No WIMPS -- only superWIMPS (Apr 25)
It will be difficult for the Large Hadron Collider at CERN, which comes
online next year, to detect "WIMPS" -- the leading dark-matter candidate
particles -- say physicists in the US. However, the collider, which will
be the world's most powerful particle accelerator, might be able to
detect a new class of particles called "SuperWIMPS" -- the decay
products of WIMPS. The detection of dark matter particles would
represent a major breakthrough in both particle physics and cosmology
(Phys. Rev. Lett. 96 151802).

US told to invest in particle physics (Apr 26)
America must boost its investment in particle physics if it is to stay
at the forefront of the discipline. That is the conclusion of a National
Academy of Sciences panel charged with recommending priorities for US
particle physics over the next 15 years. The panel believes that the
"intellectual centre of gravity" within the field is moving abroad and
that, as things stand, within a few years most American experimental
particle physicists will be working at facilities overseas.

Nuclear waste should be buried (Apr 27)
After three years of deliberation, a government-commissioned inquiry has
concluded that the UK should bury its nuclear waste deep underground.
The Committee on Radioactive Waste Management (CoRWM) laid out its
solution to the decades-old waste problem in a press conference held
today. But it told reporters that because it will take many years to
dispose of the waste in this way, the construction of a permanent
repository must be complemented by a robust system of interim storage.

Insects inspire artificial eyes (Apr 27)
Scientists in the US have made the first artificial eye using 3D polymer
structures. The eye, which is made from individual "ommatidia" -- or
single lenses -- arranged in a dome shape, is similar in structure to an
insect's compound eye. It was developed by Luke Lee and colleagues at
the University of California at Berkeley. Each ommatidium consists of a
refractive polymer microlens, a light-guiding polymer cone, and a
waveguide that together collect and direct light into an optoelectronics
detector that can recognize images. If perfected, such eyes could be
used in medicine, environmental monitoring, industry and the military
(Science 321 557).

New light on giant tilts (Apr 28)
A new theory has been proposed to explain how the giant planets --
Jupiter, Saturn and Uranus -- became tilted. The tilts of these planets
are fixed, whereas the tilts of the smaller Earth-like planets --
Mercury, Mars and Venus -- have changed with time. The new theory, which
has been developed by Adrian Brunini at the National University of La
Plata in Argentina, says that the tilts were fixed by the way the
planets interacted gravitationally as they moved from being close
together to the positions they occupy today (Nature 440 1163). If
correct, the theory would solve one of the biggest mysteries in our
solar system.


Thursday, May 04, 2006

Staggering atoms sober up in physics detox cell

Using an entirely new technology, a research team from Umeå University in Sweden has succeeded in controlling and converting energy from the random movement of atoms. “You could say that we have found a detox cell where drunken atoms can sober up,” says physicist Peder Sjölund. The findings are being published in the journal Physical Review Letters.


Physics: Thinking Back and Forward

"Physicists Contemplate Their Impact over the Last 75 Years as Their Science Expands into Diverse Frontiers

May 3, 2006--As the American Institute of Physics (AIP) celebrates its 75th anniversary this year, physicists think about how much their science has evolved and how far it has expanded into new territory. Several busy physicists have taken the time to step back from their work to reflect upon events that have transpired since that occasion in 1931 when AIP first set up shop in New York City."

In the past 75 years, breakthroughs in physics have led to life-saving medical imaging, ubiquitous computers, inexpensive worldwide telecommunications, and an ever-deepening knowledge of matter, the Earth and the universe," says Marc H. Brodsky, AIP's Executive Director and CEO.

What have been the most important events in physics during this relatively short period of time? AIP senior historian and physicist Spencer Weart suggests two discoveries which took place in the early 20th century that have had tremendous influence on how we not only see and understand our world, but also how we live in it.Quantum mechanics and Einstein’s general theory of relativity, he says, have laid down the "new physics" of our age. "


Thursday, April 27, 2006

Scientific breakthrough a step toward quantum computing

"Light is the solution. It's also the problem. That's the paradox HP Labs' Quantum Information Processing Group is beginning to unravel with its research into optical quantum computing. The group has been investigating ways to use photons, or light particles, for information processing, rather than the electrons used in digital electronic computers today. Their work holds promise for someday developing faster, more powerful and more secure computer networks."

The HP Team includes Bill Munroe and Kae Nemoto - who were both working at UQ when I was a student there. It's always great to see people I know in the news.


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Wednesday, April 26, 2006

Code for ‘Unbreakable’ Quantum Encryption Generated at Record Speed over Fiber

Gaithersburg, Md.—Raw code for “unbreakable” encryption, based on the principles of quantum physics, has been generated at record speed over optical fiber at the Commerce Department’s National Institute of Standards and Technology (NIST). The work, reported today at the SPIE Defense & Security Symposium in Orlando, Fla., is a step toward using conventional high-speed networks such as broadband Internet and local-area networks to transmit ultra-secure video for applications such as surveillance.

The NIST quantum key distribution (QKD) system uses single photons, the smallest particles of light, in different orientations to produce a continuous binary code, or "key," for encrypting information. The rules of quantum mechanics ensure that anyone intercepting the key is detected, thus providing highly secure key exchange. The laboratory system produced this “raw” key at a rate of more than 4 million bits per second (4 million bps) over 1 kilometer (km) of optical fiber, twice the speed of NIST’s previous record, reported just last month. The system also worked successfully, although more slowly, over 4 km of fiber.


Catalyst: Light Pipes - ABC TV Science

Light Pipes

6 April 2006 Funnelling daylight deep inside offices, factories and even homes is a challenge; dark corners are often too far away from the outside world for sunlight to penetrate. Now two resourceful groups in Brisbane and Sydney have devised ingenious methods for piping sunlight almost anywhere in a building, replacing the need for electrical lighting. These revolutionary inventions could save energy and reduce CO2 emissions, all courtesy of the sun


Physics could be a secret weapon in tennis. 25/04/2006. ABC News Online

A US researcher says the number of stupid mistakes made playing on the tennis court can be reduced by applying the laws of physics.

Professor Howard Brody of the University of Pennsylvania shows knowledge of the laws of matter and motion can lift a player's game in one of three main ways.

It can cut errors of latitude (hitting the ball wide), depth (hitting the net) and force (hitting the ball too hard), Professor Brody says in the current issue of the British Journal of Sports Medicine.

Australian Associate Professor of Physics Rod Cross of the University of Sydney has written a book on the science of tennis with Professor Brody.

He says physics can more accurately describe what happens when a player hits a ball than the player is aware of.

"The idea is that a physicist can tell a coach what the player's supposed to be doing and why, and the coach can translate that to a player," Professor Cross said.

"I tried it myself. I phoned up [professional tennis player] Jelena Dokic and told her she wasn't serving properly - she didn't hang up straight away."

Read more at News - The Showgirl, the Comic Strip and the Physicists

The Showgirl, the Comic Strip and the Physicists

Monday 24 April 2006

Cross-dressing singers and The Beano are not the sorts of topics you'd expect to hear discussed at a physics conference. But that's exactly what will happen at the Institute of Physics in London on Monday 24 and Tuesday 25 April when the latest methods of conserving and digitising photographs and artworks will be described.

The two-day meeting on “Preservation and Conservation Issues Related to Digital Printing and Digital Photography” will bring together physicists, conservators and chemists from museums, universities and photographic companies. Participants will hear about the latest research into the longevity of digital prints and storage methods, which we are all increasingly using to document the important events in our lives, as well as the rise of digital reproductions of fine art, and what should be considered “an original”.


Sunday, April 23, 2006

Latest PhysicsWeb Summaries


Veneto Nanotech Launches the 2nd Edition of Nanochallenge Enter your
nanotechnology business plan to Nanochallenge 2006 and you could win the
grand prize of Euro 300,000. The competition seeks commercially viable
business plans for innovative start-ups to produce and commercialize
products and services in the nanotechnology industry. Find out more at



General relativity reveals its secrets (Apr 19)
Einstein's general theory of relativity might be over 90 years old, but
it is only recently that many of its implications can be explored thanks
to advances in computing power. This is because its complex nonlinear
equations -- which describe how space--time is curved by matter and
therefore how matter moves in a gravitational field -- cannot be solved
exactly, even for the simplest situations.

Metals protect Milky Way from gamma-ray bursts (Apr 20)
Do you lie awake at night worrying that life on Earth might one day be
destroyed by a blast of gamma radiation from space? Then don't, because
a team of astronomers in the US has calculated that the probability of
such an event occurring in our galaxy is virtually zero. Krzysztof
Stanek and colleagues at Ohio State University say that gamma-ray bursts
-- the most powerful explosions in the universe after the big bang --
only tend to occur in small, misshapen "metal-poor" galaxies. Our Milky
Way is safe since it is a large spiral galaxy that contains lots of
heavy elements (astro-ph/0604113).

Google unearths physics gems (Apr 21)
Google could be a good way of measuring the "impact" of a particular
scientific paper and might even be used to replace traditional citation
indices, according to a new statistical analysis by physicists in the
US. The researchers have found that the Google PageRank algorithm, which
measures the relative importance of Web pages, can provide a systematic
way to find important papers. The technique also uncovers scientific
"gems" -- top papers overlooked by conventional searches

Wednesday, April 19, 2006


The American Institute of Physics Bulletin of Physics News
Number 774 April 19, 2006 by Phillip F. Schewe, Ben Stein, and
Davide Castelvecchi

shown up in comparisons of the spectra of hydrogen gas as recorded
in a lab with spectra of light coming from hydrogen clouds at the
distance of quasars. This is another of those tests of so-called
physical constants that might not be absolutely constant. For
example, the steadiness of the fine structure constant (denoted by
the letter alpha), defined as the square of the electron's charge
divided by the speed of light times Planck's constant, has been in
dispute ( ). Some
tests say it's changing, others say it isn't. This is an
issue since alpha sets the overall strength of the electromagnetic
force, the force that holds atoms together. Similarly, the
proton-to-electron mass ratio (denoted by the letter mu) figures in
setting the scale of the strong nuclear force. There is at present
no explanation why the proton's mass should be 1836 times that of
the electron's. The new search for a varying mu was carried out by
Wim Ubachs of the Vrije Universiteit Amsterdam. He and his
colleagues approach their task by studying hydrogen gas in the lab,
performing ultra-high-resolution spectroscopy in the
difficult-to-access extreme-ultraviolet range. This data is compared
to accurate observations of absorption spectra of distant hydrogen
(which absorbs light from even more distant quasars) as recorded
with the European Southern Observatory (ESO) in Chile. The
astronomical hydrogen is essentially hydrogen as it was 12 billion
years ago, so one can seek hints of a changing value for mu. Why
the comparison? Because the position of a particular spectral line
depends on the value of mu; locate the spectral line accurately
(that is, its wavelength) and you can infer a value for mu. In
this way, the researchers report that they see evidence that mu has
decreased by 0.002% over those 12 billion years. According to Ubachs
(, ), the statistical confidence
of his spectroscopic comparison is at the level of 3.5 standard
deviations. (Reinhold et al., Physical Review Letters, 21 April
2006, laser website at )

NUCLEAR QUANTUM OPTICS. Normally the atomic realm, characterized by
an energy scale of electron volts or less, is very much removed from
the nuclear realm, where energy levels are measured in thousands and
millions of eV. Some laser interactions in nuclei can be achieved
indirectly by using light to create plasmas, whose secondary
particles either interact with nuclei or, in a tertiary step,
produce gamma rays which then influence nuclear states. Scientists
at the Max-Planck-Institut fur Kernphysik have now studied how
present and future x-ray laser facilities will make possible direct
laser intervention in the nucleus and how this will open up a new
branch of quantum optics. X-ray sources such as the TESLA device at
the DESY lab in Hamburg will not only deliver high-intensity,
high-energy beams but will, at least partially, consist of coherent
(laserlike) radiation. One doesn't need coherent light to excite a
nucleus, but coherence can be important in exercising greater
control over optical phenomena analogous to those in atomic
systems. Examples include exciting a complete population inversion
of the target nuclei or even producing some kind of nuclear
"electromagnetically induced transparency." One of the
Thomas Burvenich (, says that an
additional benefit of nuclear quantum optics will be the direct
measurement of specific nuclear facts, such as nuclear dipole
moments and the energy levels of nuclei. (Burvenich et al.,
Physical Review Letters, 14 April 2006; lab website at )

Sunday, April 16, 2006

Latest PhysicsWeb Summaries


Veneto Nanotech Launches the 2nd Edition of Nanochallenge Enter your
nanotechnology business plan to Nanochallenge 2006 and you could win the
grand prize of Euro 300,000. The competition seeks commercially viable
business plans for innovative start-ups to produce and commercialize
products and services in the nanotechnology industry. Find out more at



Physics goes to the movies (Apr 11)
The popularity of a particular film largely depends on word-of-mouth
recommendations according to a new study by statistical physicists in
the US and Chile. César Hidalgo of the University of Notre Dame and
colleagues have also developed a quantitative indicator of a film's
quality, which they say could be used by film producers and studios to
estimate the commercial value of a movie (New J. Phys. 8 52).

Fermilab probes matter-antimatter transitions (Apr 12)
The international CDF collaboration at Fermilab has made the most
precise measurement to date of the extremely rapid transitions between
matter and antimatter. The experiment has found that certain B mesons
spontaneously turn into their own antiparticle equivalents -- anti-B
mesons -- and back again at a rate of three trillion times per second.
The result agrees well with the Standard Model of particle physics and
confirms yet again the existence of CP violation -- the reason why there
is more matter than antimatter in the universe.

Putting equilibrium on hold (Apr 13)
Physicists in the US have made the first gas that never reaches
equilibrium. David Weiss and colleagues at Penn State University
performed their experiment with a one-dimensional Bose gas of ultracold
rubidium atoms. According to the team, the gas behaves like a "quantum
Newton's cradle" -- the atomic equivalent of the popular desk toy that
has five steel balls suspended from strings in a straight line. The work
could help us better understand the behaviour of many-particle systems
and even be used in practical applications like ultrasenstive force
detectors (Nature 440 900).


Wednesday, April 12, 2006


The American Institute of Physics Bulletin of Physics News
Number 773 April 12, 2006 by Phillip F. Schewe, Ben Stein, and
Davide Castelvecchi

SHARPER FOCUSING OF HARD X RAYS has been achieved with a device
developed at Argonne National Lab. Because of their high energy, x
rays are hard to focus: they can be reflected from a surface but
only at a glancing angle (less than a tenth of a degree); they can
refracted but the index of refraction is very close to 1, so that
making efficient lenses becomes a problem; and they can be
diffracted, but the thick, variable pitch grating required for
focusing is tricky to achieve. The Argonne device is of the
diffraction type, and it consists of a stack of alternating layers
of metal and silicon, made by depositing progressively thicker
layers (see figure at ). When
the x rays fall on such a structure, nearly edge-on, what they see
is a grating pattern (called a linear zone plate) consisting of a
sort of bar-code pattern. The Argonne device succeeds so well in
focusing x rays because the position of the zones can be controlled
to within nanometer tolerances through the deposition process, and
the depth of the zones that the x rays experience can be made
arbitrarily long---microns long---by merely cutting a thicker
section of the multilayer wafer. In tests so far, one of these zone
plates, very slightly tilted to the x rays coming out of a
synchrotron source, has focused 20-keV x rays to a line only 30 nm
wide, better than previously possible. According to Argonne
researcher Brian Stephenson (, 630-252-3214), an
ideal version of this kind of x-ray lens, which they call a
Multilayer Laue Lens (MLL), should be able to focus x rays to a spot
of 1 nm or less. The likely uses for a better x-ray lens are in
full-field microscopy (making a magnified x-ray image of a sample)
or in scanning probe microscopy (by scanning the beam across a
sample). (Kang et al., Physical Review Letters, 31 March 2006)

absorbing photons from a laser, an atom can be excited to any of
various discrete energy levels allowed by quantum mechanics. What
about artificial atoms? A quantum dot, created by the same
lithographic methods used to prepare electronic chips, is nearly a
zero-dimensional zone of semiconducting material; as with electrons
inside atoms, electrons inside the confinement of a quantum dot will
also possess only a restricted menu of allowed energies. The same
is true for a pair of quantum dots 200 nm apart; with just the right
voltage applied, electrons can tunnel from one dot to the other. In
fact, an electron, considered as a spread-out quantum wave
phenomenon, can be considered to reside in both dots at the same
time, a property which makes the quantum-dot "molecule"
useful for carrying out quantum computing operations.
Now, a group of scientists have been able to probe, and to change,
the quantum energy states of a double quantum dot with sound waves,
or more particularly surface acoustic waves excited in the substrate
supporting the dots. The acoustic waves, less than1 nm in
amplitude, ripple through the surface for distances as long as
hundreds of microns as a sort of nano-earthquake, are created
through the process of piezoelectricity; a small voltage is sent
into a series of tiny electrodes painted onto the surface. This
excites the faint acoustic waves (see figure at ). The acoustic-dot
arrangement, mediated by the delicate interactions between electrons
and phonons, can work in both directions: the quantum dots can be
used to monitor the acoustic waves (which, because of their tiny
energy, are otherwise difficult to detect) or the acoustic waves can
be used to interrogate the electronic status of the dots, which
makes possible the aforesaid quantum-information applications. The
researchers involved work at the University of Twente and the Delft
University of Technology (Netherlands), NTT Corporation, Tokyo
Institute of Technology, and University of Tokyo (Japan), and Jilin
University (China). (Naber et al., Physical Review Letters, April 7
2006; contact Wouter Naber,

Tuesday, April 11, 2006

Latest PhysicsWeb Summaries


Veneto Nanotech Launches the 2nd Edition of Nanochallenge Enter your
nanotechnology business plan to Nanochallenge 2006 and you could win the
grand prize of Euro 300,000. The competition seeks commercially viable
business plans for innovative start-ups to produce and commercialize
products and services in the nanotechnology industry. Find out more at



Solitons show up in uranium (Apr 4)
Scientists have observed highly localized solitary vibrations, or
solitons, in a three-dimensional solid for the first time. The solitons
exist in crystals of uranium heated to temperatures of 450K. Although
they were predicted to exist in 3D solids some 20 years ago, conclusive
evidence for them has never been obtained until now (Phys. Rev. Lett. 96

A new look for bifocals (Apr 5)
Do you wear bifocal spectacles and get frustrated at having to move your
gaze between the upper and lower lenses as you switch from far to near
vision? If so, help could soon be at hand thanks to a new lens developed
by optical scientists in the US. It consists of a layer of liquid
crystal sandwiched between two glass surfaces, the focusing power of
which can be changed by altering the voltage applied to the lens.
Although the lens has to be manually switched on and off to change
focus, the researchers say the work could lead to lenses that
automatically adjust their focus depending on where the user is looking
(Proc. Natl. Acad. Sci. to be published).

Spray-on silicon makes its debut (Apr 7)
Researchers in Japan have unveiled a new way to make silicon-based
microelectronic devices. The method involves depositing silicon directly
onto a substrate from solution and overcomes some of the problems
associated with traditional silicon-processing lithographic techniques,
such as using sophisticated clean rooms and expensive vacuum equipment.
The researchers say the technique could lead to a way of making large,
flexible displays using "ink-jet" technology (Nature 440 783).

Water drops bounce into action (Apr 7)
What happens if you let a drop of water fall gently onto a
water-repelling surface? Physicists in France and the Netherlands who
tried the experiment were surprised by what they saw. They found that a
violent, ultra-fine jet of water emerges from the drop, moving at up to
40 times the drop's initial impact speed. The researchers believe the
unusual behaviour is caused by the collapse of an air cavity that is
created when the drop deforms as it hits the surface. The finding could
have a bearing on industrial applications in which liquids are coated on
to surfaces, such as insecticides being sprayed onto crops or in ink-jet
printing (Phys. Rev. Lett. 96 124501).

Monday, April 10, 2006

Fossil Called Missing Link From Sea to Land Animals - New York Times

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"Scientists have discovered fossils of a 375-million-year-old fish, a large scaly creature not seen before, that they say is a long-sought missing link in the evolution of some fishes from water to a life walking on four limbs on land.

In two reports today in the journal Nature, a team of scientists led by Neil H. Shubin of the University of Chicago say they have uncovered several well-preserved skeletons of the fossil fish in sediments of former streambeds in the Canadian Arctic, 600 miles from the North Pole.The skeletons have the fins, scales and other attributes of a giant fish, four to nine feet long. But on closer examination, the scientists found telling anatomical traits of a transitional creature, a fish that is still a fish but has changes that anticipate the emergence of land animals — and is thus a predecessor of amphibians, reptiles and dinosaurs, mammals and eventually humans.

In the fishes' forward fins, the scientists found evidence of limbs in the making. There are the beginnings of digits, proto-wrists, elbows and shoulders. The fish also had a flat skull resembling a crocodile's, a neck, ribs and other parts that were similar to four-legged land animals known as tetrapods."

There cna be no argument that this is a transitional fossil - removing one of the arguments used by anti-scientific "creationists." This article, by John Noble Wilford, is a commendable piece of science journalism - rather than trying to "find the other side" of evolution, he presents the evidence that exists. As Larry Krauss has recently stated, there is no other side to evolution.

Read more at (free registration required)

Sunday, April 09, 2006

Liquid Flowing Uphill to Cool Chips, Entangled Photon Holes, Sunlight from LED

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LIQUID FLOWING UPHILL; MIGHT BE USED TO COOL CHIPS. In a phenomenon known as the "Leidenfrost effect," water droplets can perform a dance in which they glide in random directions on a cushion of vapor that forms between the droplets and a hot surface. Now, a US-Australia collaboration (Heiner Linke, University of Oregon, shows that these droplets can be steered in a selected direction by placing them on a sawtooth-shaped surface.
Heating the surface to temperatures above the boiling point of water creates a cushion of vapor on which the droplet floats. The researchers think that the jagged sawtooth surface, acting as a sort of ratchet, redirects the flow of vapor, creating a force that moves the droplet in a preferred direction. The droplets travel rapidly over distances of up to a meter and can even be made to move up inclines. This striking method for pumping a liquid occurs for many different liquids (including nitrogen, acetone, methanol, ethanol and water) over a wide temperature range (from - 196 to + 151 C).
A practical application of this phenomenon might be to cool off hot computer processors. In a concept the researchers plan to test, waste heat in a computer would activate a pump moving a stream of liquid past the processor to cool it off. Such a pump for coolants would need no additional power, have no moving parts, and would spring into action only when needed, when the processor gets warm. (Linke et al., Physical Review Letters, upcoming;)

ENTANGLED PHOTON HOLES. In some semiconductor devices, such as light-emitting diodes, an applied voltage can dislodge electrons from some atoms, leaving behind a hole which behaves in some situations as if it were a positively charged particle in its own right. A "current" of holes can move through the material and the holes can recombine later with electrons to produce light. In very loose analogy, James Franson (Johns Hopkins) suggests that photonic holes might be created; a photon hole, to give one example, would be a place in an otherwise intense laser-beam wavefront where a photon had been removed (by passing the laser beam through vapor, forinstance). Not only can there be photon holes, Franson (443-778-6226, suggests, but the holes can be entangled, meaning that their quantum properties would be correlated, even if far apart from each other. Such entangled photon-holes would be able to propagate through optical fibers just as well as entangled photons, but might be even more robust against the decoherence (the undoing of the quantum correlations) that plagues present efforts to establish quantum information schemes.

Franson expects to do put his idea to experimental test in the next few months. (Physical Review Letters, 10 March 2006)

SUNLIGHT ON A CHIP. A new LED design employs a handy combination of light and phosphors to produce light whose color spectrum is not so different from that of sunlight. Light emitting diodes (LEDs) convert electricity into light very efficiently, and are increasingly the preferred design for niche applications like traffic and automobile brake lights. To really make an impression in the lighting world, however, a device must be able to produce room light. And to do this one needs a softer, whiter, more color balanced illumination. The advent of blue-light LEDs, used in conjunction with red and green LEDs, helped a lot. But producing LED light efficiently at blue, red, and yellow wavelengths is still relatively expensive, and an alternative approach is to use phosphors to artificially achieve the desired balance, by turning blue into yellow light. Scientists at the National Institute for Materials Science and at the Sharp Corporation (in Japan) have now achieved a highly efficient, tunable white light with an improved yellow-producing phosphor. Their light yield is 55 lumens per watt, about twice as bright as commercially available products operating in the same degree of whiteness. (Xie et al., Applied Physics Letters, 6 March 2006; contact Rong-Jun Xie,


The American Institute of Physics Bulletin of Physics News
Number 772 April 5, 2006 by Phillip F. Schewe, Ben Stein, and
Davide Castelvecchi

NASA - Magnetic Moondust

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Thirty-plus years ago on the moon, Apollo astronauts made an important discovery: Moondust can be a major nuisance. The fine powdery grit was everywhere and had a curious way of getting into things. Moondust plugged bolt holes, fouled tools, coated astronauts' visors and abraded their gloves. Very often while working on the surface, they had to stop what they were doing to clean their cameras and equipment using large--and mostly ineffective--brushes.

Dealing with "the dust problem" is going to be a priority for the next generation of NASA explorers. But how? Professor Larry Taylor, director of the Planetary Geosciences Institute at the University of Tennessee, believes he has an answer: "Magnets".


Thursday, April 06, 2006

Black Bodies and Quantum Cats - Jennifer Ouellette talks to NPR about her new physics book

Weekend Edition Sunday, April 2, 2006 · Jennifer Ouellette is a self-described "physics phobe" who couldn't tell a quark from a cathode ray. But after successfully avoiding the subject for more than 25 years, she stumbled into science writing as a freelance journalist. That led her to explore the fundamentals of physics from a cultural and historical perspective.

Ouellette's new book is Black Bodies and Quantum Cats, subtitled "Tales from the Annals of Physics." The author tells Liane Hansen she hopes readers will see that physics is more than a cold, hard discipline: it has emotional content

Sunday, April 02, 2006

Black Hole Merger Movie and A Submersible Holographic Microscope

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Science Fair Central offers ideas for science fair projects and experiments

BLACK HOLE MERGER MOVIE.  Accurate calculations of the gravitational waveforms emitted during the collision of black holes can now be made.  A new computer study of how a pair of black holes, circling each other,  disturbs the surrounding space and sends huge gusts of
gravitational waves outwards, should greatly benefit the experimental search for those waves with detectors like LIGO and LISA. The relative difficulty of computer modeling of complicated physical behavior depends partly on the system in question and on the equations that describe the forces at work. To describe the complicated configuration of charges and currents, one uses Maxwell's equations to determine the forces at work. In the case of black-hole binaries, the equations are those from Albert Einstein's theory of general relativity. Black holes encapsulate the ultimate in gravitational forces, and this presents difficulties for
computations attempting to model behavior nearby. Nevertheless, some physicists at the University of Texas at Brownsville have now derived an algorithm that not only produces accurate estimates of the gravity waves of the inspiraling black holes, even over the short time intervals leading up to the final merger, but also is
easily implemented on computers (see figures and movie at ). "The importance of this work," says
Carlos Lousto, one of the authors of the new study, "is that it gives an accurate prediction to the gravitational wave observatories, such as LIGO, of what they are going to observe." The new results are part of a larger study of numerical relativity carried out at the University of Texas, work referred to as the
Lazarus Project ( ).
(Campanelli, Lousto, Marronetti, and Zlochower; Physical Review Letters, 24 March 2006; contact information,, 956-882-6651)

A SUBMERSIBLE HOLOGRAPHIC MICROSCOPE. A new device allows scientists to form 3D images of tiny marine organisms at depths as great as 100 m. The device allows the recording of behavioral characteristics of zooplankton and other marine organisms in their natural environment without having to bring specimens to the surface for examination. Scientists at Dalhousie University in Halifax, Canada, used the hologram arrangement originally invented by Denis Gabor: light from a laser is focused on a pinhole that acts as a point source of light if the size of the hole is comparable to the wavelength of light. The spherical waves that emanate from the
pinhole illuminate a sample of sea water. Waves scattered by objects in the sea water then combine at the chip of a CCD camera with un-scattered waves (the reference wave) from the pin hole to form a digitized interference pattern or hologram. The digital holograms are then sent to a computer where they are digitally
reconstructed with specially developed software to provide images of the objects. The Dalhousie researchers packaged their holography apparatus in such a way that the laser and digital camera parts are in separate watertight containers, while the object plane is left open (see figure at ). One
difficulty was to get container windows of optical quality that are thin enough for high resolution imaging but thick enough to resist sea pressure. The new submersible microscope can also record the trajectories of organisms in the sample volume so that movies of the swimming characteristics of micron size marine organisms can easily be produced. Holograms with1024 x 1024 pixels can be recorded at 7
to 10 frames/s. This requires a large bandwidth for data transmission to a surface vessel and was accomplished with water tight Ethernet cables. Imaging volumes can be several cubic centimeters depending on the desired resolution. The Gabor geometry
allowed the Dalhousie researchers to design a very simple instrument capable of wavelength limited resolution of marine organisms in their natural environment. Past generations of submersible holographic microscopes had lower resolution, weighed several tons, had to be deployed from large ships, and used high-resolution film
as the hologram recording medium. This meant that only a small number of holograms could be recorded. In contrast, the Dalhousie instrument only weighs 20 kg, can be deployed from small boats or even pleasure vessels, and can record thousands of holograms in a few minutes so that the motion of aquatic organisms can be captured
in detail. (Jericho et al., Review of Scientific Instruments, upcoming article; contact M.H. Jericho, Dalhousie University,, and also the Universidad Nacional de Columbia)

The American Institute of Physics Bulletin of Physics News
Number 771 March 29, 2006 by Phillip F. Schewe, Ben Stein, and
Davide Castelvecchi


March 30, 2006
a biweekly tip sheet for journalists from the National Institute of Standards and Technology

Quantum Dot Method Rapidly Identifies Bacteria
A rapid method for detecting and identifying very small numbers of diverse bacteria, from anthrax to E. coli, has been developed by scientists from the National Cancer Institute and NIST. Described in the March 28 issue of Proceedings of the National Academy of Sciences, the work could lead to the development of handheld devices for accelerated identification of biological weapons and antibiotic-resistant or virulent strains of bacteria­-situations where speed is essential.

RFID Tags to Assist in Tracking First Responders
Radio Frequency Identification (RFID) technology has been around for many years and is widely used to identify, track and communicate information about items, products and even animals. An interdisciplinary team of NIST researchers is studying whether RFID technology can be used as a low cost, reliable means to track firefighters and other first responders inside buildings and help them navigate under hazardous conditions.

NIST/ORNL Dedicate New Nuclear Medicine Lab
NIST is establishing a satellite facility at Oak Ridge National Laboratory in Oak Ridge, Tenn., to promote measurement accuracy for nuclear medicine imaging. In a dedication ceremony at the new laboratory today (March 30), NIST Director William Jeffrey and ORNL Director Jeff Wadsworth described the program, which is a pilot test for a planned series of such sites around the country.

Quality Standards Issued For Testing Herbal Products
NIST has issued the first suite of Standard Reference Materials (SRMs) in a planned series of reference materials for botanical dietary supplements. Manufacturers can use these materials for quality control, and researchers can use them to ensure that their laboratory analyses of supplements are accurate.

Measuring Electrical Arcs At the Micrometer Scale
A new device and technique have been developed by NIST researchers for measuring “breakdown” voltage­-the voltage required to produce electrical arcs when electrodes are 400 nanometers to 45 micrometers apart. The advance could be useful in microelectronics, such as in the design of microelectro-mechanical systems (MEMS), in which arcing could cause device failure.

Bytes by the Quintillion For Today and Tomorrow
Engineers and information specialists from government, industry and academia agreed this month at a NIST workshop that immediate action is needed to keep vast amounts of digital knowledge from disappearing into cyberspace or becoming in 200, or even 20 years, as incomprehensible as the markings on Babylonian cuneiform tablets.

“March Madness” Effects Observed in Ultracold Gases
Physicists at Harvard University, George Mason University and NIST have discovered new quantum effects in ultracold gases that may lead to improved understanding of electrical conductivity in metals. In work presented at the March meeting of the American Physical Society in Baltimore, Md., the researchers calculated the properties of an “artificial crystal” of ultracold atoms in a lattice formed by intersecting laser beams.

Quick Links

NIST Proposes Updating Digital Signature Standard

To keep current with changing technology, NIST is proposing several changes to the Digital Signature Standard (DSS). The draft Federal Information Processing Standard (FIPS) 186-3 allows the use of 1024, 2048, and 3072-bit encryption keys.

Rescue Robots Test Skills At ‘Disaster City’ Event
Ground, aerial and aquatic emergency response robots from across the country will face real-life challenges April 4-6 in tests of their life-saving skills at Texas A&M University’s "Disaster City" in College Park, TX. The event, hosted by Texas A&M Engineering Extension Service and the local Federal Emergency Management Agency Task Force, is the second in a series of evaluation exercises conducted by NIST for urban search-and-rescue robots.

IT Meeting to Help Agencies With Security Assessments
NIST will host a workshop at its headquarters in Gaithersburg, Md., on April 26 to help federal agencies comply with FISMA (Federal Information Security Management Act) through the development of uniform requirements for security assessment service providers.

Chenok Set To Chair IT Security Advisory Board
NIST Director William Jeffrey has appointed Daniel J. Chenok, a prominent leader in the information technology industry, as the new chair of the Information Security and Privacy Advisory Board. The Board advises NIST on emerging managerial, technical, administration, and physical safeguard issues related to information security and privacy issues.

Collins Named to Head NIST Technology Services
Belinda L. Collins, an expert in both the technical and policy related aspects of standards development, has been promoted to director of NIST's Technology Services.

Saturday, April 01, 2006

Virtual Swimmer to Speed Up Australia's Pool Times

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CSIRO and the Australian Institute of Sport are using mathematics in a bid to speed up our top swimmers by testing changes to swimming strokes.

The research will make use of the same software CSIRO uses for other fluid simulations such as animating water for movies and modelling volcanoes and tsunamis. Researchers are hoping to see some practical results in time to implement improvements for the London Olympics in 2012.

Read More at Virtual swimmer to speed up our athletes

Bullet-shaped scramjet put to the test

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UQ Press Release
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Scramjet Clocks Nearly Mach 10

The HyShot team from UQ have tested a new version of their SCRAMjet engine (an engine designed to burn fuel passing through it at supersonic speeds). This test flight is believed to have reached speeds of Mach 7.

March 30th 2006: The HyShot™ IV experimental scramjet test has been conducted today at the Woomera range, 500km north of Adelaide, South Australia at about 1.10pm local time (CDT).

“The rocket launch looked as expected. We had another clean liftoff,” Associate Professor Michael Smart of the UQ HyShot team said.

Quantum Mechanics and Quantum Physics

In the words of Niels Bohr "anybody who thinks they understand quantum physics is wrong." Quantum mechanics describes how the very small particles like electrons and atoms behave in ways contrary to most intuition. Discover the weirdness of quantum mechanics and how it is changing the way we make computers and secret codes through quantum computing and cryptography. Learn about the Heisenberg Uncertainty Principle and how it constrains how much we can know about a particle.

The 2005 Nobel Prize in Physics

The 2005 Nobel Prize in Physics is devoted to optics, with half of the prize going to Roy J. Glauber of Harvard University for his quantum theory of optical coherence, and one-quarter each going to John L. Hall and Theodor W. Hänsch, for their development of ultra-high-precision measurements of light.

1927 Solvay Conference Film
One of the most famous photos in the history of physics captures the illustrious participants at the fifth Solvay Conference in Brussels, October 1927. 29 physicists, the main quantum theorists of the day, came together, 17 of the 29 attendees were or became Nobel Prize winners. This is a home movie shot by Irving Langmuir, (1932 Nobel Prize winner). Twenty-one of the 29 attendees are on the film. The film includes shots of Erwin Schrödinger, Albert Einstein, Marie Curie, Dirac and Niels Bohr.

The Quantum Computer
By exploiting the unusual properties of Quantum Physics, physicists hope to make a computer that is, in many ways, better and faster than any computer that can ever possibly be built using the techniques of “classical” electronics.

Visual Quantum Mechanics

Instructional units that introduce quantum physics to high school and college students who do not have a background in modern physics or higher level math using interactive computer programs and digital multimedia in an activity based environment

What is Quantum Physics
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New Scientist's Guide to The Quantum World
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Quantum Physics Online Course
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Bell's theorem and Einstein-Podolsky-Rosen Paradox FAQ
Bell's Theorem and the EPR paradox have important ramifications on possible communication faster than the speed of light. An introduction to the problem of measurement of quantum entangled particles from the Usenet newsgroups.

Bell Experiment with Independent Observers
An excellent description of experimental investigations of Bell's theorem, which investigate fundamental philosophical issues of Quantum Physics

Friday, March 31, 2006

I Honestly Don't Know if This is Real...

or just "seasonal"

"You are deep underground in a lab that once housed some of the finest minds in chemistry. But robots directed by a crackbrained artificial intelligence have taken it over and plan to use its equipment to destroy the world! After freezing an evil robot with your handy wrist-mounted hot-and-cold gun, you reach the Haber-Bosch room. And now you must correctly synthesize ammonia or die."

Critical Mass: The Chemistry Video Game

I mean, it must be an april fool, right?

ESA - Space Science - Home - Cluster and Double Star witness a new facet of Earth’s magnetic behaviour

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Cluster and Double Star witness a new facet of Earth’s magnetic behaviour

30 March 2006

Five spacecraft from two ESA missions unexpectedly found themselves engulfed by waves of electrical and magnetic energy as they travelled through Earth’s night-time shadow on 5 August 2004. The data collected by the spacecraft are giving scientists an important clue to the effects of 'space weather' on Earth’s magnetic field.


Conduct Your Experiment

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First of all, gather together everything you need for your experiment before you get started. Doing this means you wont be interrupted, so that your momentum will be maintained and you will get through the experiment as efficiently as possible.

Follow the steps you designed earlier as closely as possible. If the results are very different to what you expected, you might need to modify your procedures on the fly. In that case, be sure to note down (in your notebook – where else?) any changes you make to your experiment, so that you can include them in your report. When you need to modify the experiment, you should consider why things are not going as expected – is your hypothesis wrong, or are there assumptions that need to be rethought? Does your new design still answer the question you are interested in? It's perfectly fine to move to a new question if something more interesting comes up in the moment.

As you go through the experiment, record notes on your materials used, your observations and any thoughts you have about the experiment – they might be useful when you come to writing your report. Obviously, you need to record all the results of your experiments – ideally in a table format, with dependent variable measurements cross-referenced with their corresponding independent variable settings.

You should take the mean of several identical trials for each set of independent variables. This is done to minimize the effects of the uncontrollable random events that affect most experiments. Virtually anything can happen once or twice, so single results do not form a very convincing argument for or against your hypothesis. The more trials, the better. Depending on your level, you might be required to perform more a complicated statistical analysis – in this case, it is especially important to record every result, so that you can take means and find standard deviations and errors as required. This sort of analysis will tell you how accurate or reliable your results are.