Your Guide to Physics: March 2006

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

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

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.

Thursday, March 30, 2006

An Hypothesis

An hypothesis is an educated guess about the answer to your question. You did educate yourself with all the research, right? Your experiment will either support or disprove your hypothesis.

Remember, your hypothesis need not be right – disproof is a result too! In fact, many of the greatest discoveries have come from the disproof of an hypothesis.

Generally your hypothesis should be stated clearly, with the lines of reasoning and supporting facts you used to generate it. It is very important that you generate some sort of hypothesis before you start your experiment proper – without some idea of what you are looking for, it is hard to design an experiment, and usually even harder to understand the results.

Designing an Experiment

Your experiment needs to be designed so that it tests your hypothesis. The key point to designing an experiment is to control your variables.

Variables are anything that can affect the outcome of your experiment. There are three important classes of variables to consider:

Independent variables are the few (or even better, one) quantities that you deliberately vary during your experiment, in order to asses their affects.
Dependent variables are the ones that change in response to your deliberate variations of the independent variable. At least, your hypothesis says they will.
The remaining variables are usually fixed at the same value from trial to trial, and are called controlled variables. Also variables that do change, but not in an important way between trials. For example, in many experiments the time of day, which changes as you conduct trial after trial, will not be important. However, bear in mind these variables that are incompletely controlled – if your hypothesis fails, these are often the first place you should look for an explanation.

You also need to bear in mind confounding variables. These are variables that change in an important way during your experiment, but you don't control, or at least account for. For example, if you were testing an hypothesis relating the amount of light in a room to the position of the dimmer switch, you would need to account for the differences in light coming in through the windows if some of your trials were conducted in the morning and some were late at night.

Be very careful if you do have more than one independent variable in your experiment. You need to know what variations are due to which changes. Only vary one independent variable at a time – this way you will be able to see the independent affects, then you can try varying them together to see if there are any interesting relationships.

You should draw a diagram of your experiment before you get started. Be sure to list everything you need, so you can have it on hand and just do the experiment. Nothing kills momentum like having to stop and find some more items you forgot you needed.

Wednesday, March 29, 2006

How to Pour Ketchup (Catsup, Tomato Sauce)

Are you one of those people who taps at the bottom of an inverted ketchup bottle, waiting in frustration for the sauce to pour? I am speaking of traditional ketchup bottles, not squeeze tubes, wide-mouth jars, or bottles designed to stand on their heads. Have you ever wondered if there is a right way to do it – a way that works, and makes scientific sense?

Yes, folks, there is a right way to do it, and it does make sense. Here is how, and why:

Tuesday, March 28, 2006

Extreme Thinking and Tough Learning

Michael Neilsen, a professor at my undergraduate school, UQ, wrote about "Tough Learning" - the special challenges to the way we think and learn posed by the natural sciences.

You will notice that this essay was written in 2003 - but it only recently came my way.

Seed: Prime Numbers Get Hitched

In their search for patterns, mathematicians have uncovered unlikely connections between prime numbers and quantum physics. Will the subatomic world help reveal the elusive nature of the primes?

by Marcus du Sautoy

Sunday, March 26, 2006

Physics Glossary

A

abberation

Absolute Temperature

absolute zero

absorptance

absorption lines

acceleration

Accretion Disk

Acoustic Spectrum

Adhesion

Adiabatic Change

admittance

Airy points

albedo

allowed transition

alpha decay

alpha particle

Alpha Ray

altimeter

Ampere

Ampere's law

amplitude

AMU

angle of deviation

angle of incidence

angle of reflection

angle of refraction

angstrom

angular momentum

angular velocity

annihilation

antibubble

antiferromagnetism

antimatter

antinode

antiparticle

Arago Point

Archimedes' Principle

astigmatism

atm

atmospheric pressure

B

band theory of solids

barn

Bernoullis' law

black-body

black-body radiation

black-body temperature

boiling

bremsstrahlung

bubble

C

c - Speed Of Light

charge

critical point

critical pressure

change of state

chromatic aberration

color charge

color force

coma

compton effect

conductivity

critical temperature

D

dark matter

derivative

diamagnetism

diffraction grating

dimensions

dioptre

distortion

divergence

E

electric field

electrokinetic

elementary particle

energy

entropy

F

Faraday's law of induction

ferromagnetism

force

fluid

free body diagram

freezing

frequency

friction

G

Galilean Transformation

gas (fluid dynamics)

gas (thermodynamics)

graviton

gravity

H

heat capacity

heat death

hidden variables theory

hydrostatic approximation

I

image

J

K

kelvin

L

laminar flow

lens

light year

liquid

M

magnetism

N

nanotechnology

neutrino

nuclear physics

O

Order of Magnitude

orbital

P

paramagnetism

photoelectric effect

photon

physics Planck's Radiation Law

plasmon

Q

quantum

quantum chromodynamics

quantum cryptography

quantum gravity

quark

R

radio

Radioactive Age

Radioactive Equilibrium

radioactivity

radioastronomy

radio frequencies

Reynolds' number

Root Mean Square (RMS) value

S

scanning tunelling microscope (STM)

shearing force

solid

spherical aberration

star

steam point

Stirling Cycle

STM (scanning tunelling microscope)

strain

streamfunction

streak line

streamline

string (string theory)

superstring theory supersymmetry

surfactant

T

tachyon

temperature

temperature scales

thermodynamics

turbulent flow

U

V

valence electron

vector

velocity

viscosity

W

X

Y

year

Z

Z boson

Saturday, March 25, 2006

AIP Physics News - Two Dimensional Light, Nanopores and Zeptomole Biology

PHYSICS NEWS UPDATE

The American Institute of Physics Bulletin of Physics News
Number 770 March 23, 2006 by Phillip F. Schewe, Ben Stein

Elsewhere on the Web
Weird Light and Plasmons
Engineers study 'light on a wire'
Developing Nanopores as Probes

TWO-DIMENSIONAL LIGHT, OR PLASMONS, can be triggered when light strikes a patterned metallic surface. Plasmons may well serve as a proxy for bridging the divide between photonics (high throughput of data but also relatively large circuit dimensions---1 micron) and electronics (relatively low throughput but tiny dimensions---tens of nm). One might be able to establish a hybrid discipline, plasmonics, in which light is first converted into plasmons, which then propagate in a metallic surface but with a wavelength smaller than the original light; the plasmons could then be processed with their own two-dimensional optical components (mirrors, waveguides, lenses, etc.), and later plasmons could be turned back into light or into electric signals. To show how this field is shaping up, here
are a few plasmon results from that great international physics bazaar, the APS March Meeting, which took place last week in Baltimore.

Plasmons in biosensors and cancer therapy: Naomi Halas (Rice Univ) described how plasmons excited in the surface of tiny gold-coated rice-grain-shaped particles can act as powerful, localized sources of light for doing spectroscopy on nearby bio-molecules. The plasmons's electric fields at the curved ends of the rice are much more intense than those of the laser light used to excite the plasmons, and this greatly improves the speed and accuracy of the spectroscopy. Tuned a different way, plasmons on nanoparticles can be used not just for identification but also for the eradication of cancer cells in rats.
Plasmon microscope: Igor Smolyaninov (Univ. Maryland) reported that he and his colleagues were able to image tiny objects lying in a plane with spatial resolution as good as 60 nm (when mathematical tricks are applied, the resolution becomes 30 nm) using plasmons that had been excited in that plane by laser light at a wavelength of 515 nm. In other words, they achieve microscopy with a spatial resolution much better than diffraction would normally allow; furthermore, this is far-field microscopy---the light source doesn't have to be located less than a light-wavelength away from the object. This work is essentially a Flatland version of optics. They use 2D plasmon mirrors and lenses to help in the imaging and then conduct plasmons away by a waveguide.
Photon-polariton superlensing and giant transmission: Gennady Shvets (Univ. Texas) reported on his use of surface phonons excited by light to achieve super-lens (lensing with flat-panel materials) microscope resolutions as good as one-twentieth of a wavelength in the mid-infrared range of light. He and his colleagues could image subsurface features in a sample, and they observed what they call "giant transmission," in which light falls on a surface covered with holes much smaller than the wavelength of the light. Even though the total area of the holes is only 6% of the total surface area, 30% of the light got through, courtesy of plasmon activity at the holes.
Future plasmon circuits at optical frequencies: Nader Engheta (Univ. Pennsylvania) argued that nano-particles, some supporting plasmon excitations, could be configured to act as nm-sized capacitors, resistors, and inductors---the basic elements of any electrical circuit. The circuit in this case would be able to operate not at radio (10¹⁰Hz) or microwave (10¹² Hz) but at optical (10¹⁵ Hz) frequencies. This would make possible the miniaturization and direct processing of optical signals with nano-antennas, nano-circuit-filters, nano-waveguides, nano-resonators, and may lead to possible applications in nano-computing, nano-storage, molecular signaling,and molecular-optical interfacing.

NANOPORES AND ZEPTOMOLE BIOLOGY. Some proteins naturally form nanometer-scale pores that serve as channels for useful biochemical ions. Through this ionic communication, nanopores enable many functions in cells, such as allowing nerve cells to communicate
(they are even responsible for twitching the frog leg in Galvani's famous discovery in the 1700s). Nanopores can be destructive too. When the proteins of bacteria and viruses attach to a cell, their
nanopores can facilitate infection, for example by shooting viral DNA through them into the cell. At the APS March Meeting, NIST's John J. Kasianowicz showed how single biological nanopores can be used to detect and characterize individual molecules of RNA and DNA. He also demonstrated constructive uses for anthrax-related nanopores in diagnosing anthrax infections and testing anti-anthrax drugs. Anthrax bacteria secrete a protein called "protective antigen" that attaches to an organic membrane such as a cell wall. The protein forms a nanopore that penetrates the membrane. When another anthrax protein called "lethal factor" attaches to the protective antigen nanopore, it prevents ionic current from flowing through the pore (and out of the
organic membrane). By monitoring animal blood samples for changes in ion current, Kasianowicz and his colleagues at the National Cancer Institute and the United States Army Medical Research Institute for Infectious Diseases electronically detected a complex of two anthrax proteins in less than an hour, as opposed to the existing methods which can take up to several days. Also, they demonstrated a method for screening potential therapeutic agents against anthrax toxins
using the anthrax nanopore (see Anthrax at NIST for a picture and more information).

A Brown University group led by Sean Ling was among those reporting progress in developing a nanopore-based method for sequencing DNA faster and more cheaply than traditional
biochemical techniques. In one scenario the change in ion current as DNA moves through the nanopore could yield the sequence of bases (letters) in the DNA. However, the letters in DNA are so close to each other (about 4 angstroms) and the DNA moves so quickly through the nanopore that researchers have had to come up with creative solutions for reading the individual letters. For example, the Brown group attaches complementary blocks of DNA, about 6 letters long, to the DNA sequence of interest, so that the researchers would read blocks of multiple letters at a time, while slowing down the passage of the DNA by attaching a magnetic bead to it. Other researchers are finding value in developing nanopores for fundamental biology studies. Discussing his group's latest work with artificial, silicon-based nanopores, Cees Dekker of the Delft University of Technology showed how lasers and other manipulations with the artificial pores are enabling new
single-molecule (zeptomolar) biophysics studies on the properties of DNA, RNA, and proteins by studying how they pass through the pores (see www.aip.org/png for an artist's rendering of DNA traversing through a nanopore)

NASA - Was Einstein Wrong About Space Travel?

March 22, 2006: Consider a pair of brothers, identical twins. One gets a job as an astronaut and rockets into deep space. The other stays on Earth. When the traveling twin returns home, he discovers he's younger than his brother.

This is Einstein's Twin Paradox, and although it sounds strange, it is absolutely true. The theory of relativity tells us that the faster you travel through space, the slower you travel through time. Rocketing to Alpha Centauri—warp 9, please—is a good way to stay young.

Or is it?

Nanotechnology - Taking it to the People

This topic is sponsored by the Australian Research Council Nanotechnology Network.

The business of working with the ultra small promises to become mega big. But what you’ll actually see in the marketplace may not look all that different from what’s around us today.Unlike information technology – where it’s easy to spot new products like computers, iPods or mobiles – consumers won’t be buying ‘nanotechnology products’ so much as products developed or enhanced through nanotechnology.

Just because nanotechnology may not always be easy to spot, that doesn’t mean that it won’t be making big impacts on the world in the next decade.

How might nanotechnology impact on your world in the next 10 to 20 years? Let's consider the two biggest investments made by most families – the house and car.

Read more at www.science.org.au/nova...

Tuesday, March 21, 2006

Journal Gazette | 03/20/2006 | Physics plays havoc with basketball jump shots

Elsewhere on the Web
Basketball.com
Physics of basketball
Make a Jumpshot every time

"As March Madness in NCAA basketball continues, I thought that it might be fun to consider some of the scientific principles and modern technologies used by players and coaches to improve individual performance.

For example, the angle at which the ball is thrown toward the basket obviously is critical to the success of the shot. This angle of approach should be as large as possible so that as the ball travels downward toward the basket, it has the largest hoop target area through which to pass.If a player throws the ball at a shallow angle, the target area relative to the ball becomes more elliptical in shape and effectively smaller in size, leaving little margin for error.

Unfortunately, launching the ball at a steeper angle also requires more effort and greater control. Should a player then try to shoot at a larger angle at distances far from the basket by exerting more effort but sacrificing control, or is it preferable to reduce the exertion and increase control by launching the ball at a smaller angle?"

Saturday, March 18, 2006

Dimensional Analysis of a Pendulum Period

If a pendulum is taken to Mars, how would its period change?

Q) If a pendulum has a period of 4s on the earth, what would its period be if it were placed on Mars? (Use g_M/g_E~ 1/3.) Use only dimensional analysis.

A) First, we must determine the relationship between the pendulum's period and gravity.

The period (P) of a pendulum of length l is a time, so

if P α l^ag^b

T=[l]^a[g]^b

T=L^a(L/T²)^b

Thus, a=1/2 and b=-1/2

P α √(l/g)

Now, if we move to Mars, we don't change the length of the pendulum - Thus:

T_M=T_E√(g_E/g_M)

T_M=(4s)√3

T_M~7s

Dimensional Analysis

What is Dimensional Analysis, and what is it for?

Dimensional analysis is a technique used by physicists (and other scientists) to check the validity of equations. It is often also used to arrive at the equations in the first place! The basic principle of Dimensional analysis is the common sense principle that you need to compare apples with apples. In physics, this translates to “for two quantities to be equal, they must have the same dimensions.” That is, if the object on the left hand side of an equals sign must have the same dimensions as the quantity on the right hand side.

But, what are dimensions?

The dimension of an object tells you what sort of quantity it is. There are four basic dimensions, Length (L), Mass (M), Time (T) and Electric Charge (Q), corresponding to the four basic quantities. The dimensions of more complicated quantities can be expressed as powers of these four. A useful property of dimension is that the dimension of a product, is the product of the dimensions, that is the dimension of x*y is the dimension of x times the dimension of y. Furthermore, the arguments to exponential, trigonometric and logarithmic functions must be dimensionless numbers, which is often achieved by multiplying a certain physical quantity by a suitable constant of the inverse dimension.

For example, you might want to know the dimensions of a force: From Newton’s Laws, we know that force is mass times acceleration, and as the SI units for acceleration are m/s², we know that the dimensions of force must be the product of the dimensions of mass (M) and acceleration (L/T²). That is, the dimensions of force (usually written [force]) are ML/T². Similarly, [velocity] is L/T.

How do I use this to find equations?

Say you’re in a basic motion exam, and you are trying to solve a problem like

“a 10kg ball is thrown upwards from ground level on the moon (where gravity is one sixth that of earth) with an initial speed of 15 m/s. How high will it be after 2 seconds, 5 seconds and 10 seconds? When will it bounce?”

Now, you remember that there was a formula in your notes that told you the displacement (s) of a mass after some time (t), given its initial velocity (u) and the constant acceleration (a), but you can’t quite remember it – was it

“s=ut²+1/2 a²t” or “s=ut+1/2 at”?

you’re not sure about the exponents (the “squares”), but you are pretty sure that you’ve got the symbols in the right places, and you know that that ½ is definitely there – how do you go about checking the formula?

Let’s start with the first guess, and compare the dimensions of the terms:

[s]=L as displacement is a length, so we need the dimensions of the other two terms to L also. [ut^2] = [u][t]^2=L/T*T²=LT! Clearly this term is incorrect, but let’s check the second term as well:

[1/2 at]=[1/2][a][t], but ½ is just a number – or in the terminology of physics: it is dimensionless, so we can say [1/2]=1. Then [1/2 at]=1*L²/T⁴*T=L²/T³! Not only does this term not match the displacement, it doesn’t even match the ut² term it is added to! Just as we cannot compare apples and oranges, we can’t add apples to oranges!

If you have a look at the second guess, you’ll see that it is also wrong, so we need another guess – but, if we look at our first guess, the first term had am extra T, so if we remove one of the times from it, it will have the correct dimension so it must be ut. The second term is wrong by a factor of L/T³, which could be explained by having one too many accelerations and one too few times – so it should be ½ at². No doubt you’ve now seen one of the shortcomings of dimensional analysis – at no point in our calculation, have we been able to make any conclusion about whether the ½ was correct – all we know is that there is some dimensionless object in front of each term – it could be one, it could be ½ or it could be p – and there could be a different one in front of the ut term. Unfortunately, dimensional analysis doesn’t tell us anything about particular dimensionless constants, those you will have to remember (or work out some other way – if you know calculus, the laws for constant acceleration come from integrating Newton’s Second Law – twice in this case).

So know we know that “s=ut+1/2 at²” with out having had to remember it exactly. This is a useful exam time saver – if you’re struggling to recall a formula, you can at least rule out dimensionally inconsistent guesses quickly, leaving more time to find the correct option.

Can it do more?

Of course it can – with Dimensional analysis, you can make a pretty good guess as to the structure of equations you have never been shown.

How can I possibly guess equations I’ve never been taught?

Well, first of all, we have to go back to the principle of comparing apples to apples. So, if say you want to come up with the formula for the vibration frequency of a mass on a spring, you know that what ever the formula you’re looking for is, it has to have the same dimensions as frequency. As frequency is a measure of how many times something happens per unit of time, you can see that [frequency] is T^-1.

The second step is to identify all the things that the frequency could depend upon. If you’ve studied springs at all, you will know that they obey Hooke’s Law: the restoring force (F) pulling (or pushing) a stretched (or compressed) spring back to its equilibrium point is proportional to the distance (s) the spring has been stretched or compressed. The constant of proportionality, traditionally called “k”, completely describes how stiff the spring is (so you don’t need to worry about the properties of the metal the spring is made from or the physical size and shape of the spring). Also, it seems clear that heavy masses and light masses will move at different speeds, so the only terms we need to worry about are the spring constant (k) and the mass (m).

So, we guess that the frequency will have some sort of power relationship to the mass and spring constant:

“f=m^x*k^y”

where x and y are constants that are to be determined. Now, we apply the apples to apple rule and choose x and y so that the dimensions on the left and right hand side match.

[f]=1/T

[m]^x=M^x

[k]^y=??

To evaluate the dimensions of k, we need to go back to our definitions:

Hookes Law: F=-ks (the minus sign indicates that the force is in the opposite direction to the stretching)

So, from Hooke’s Law, we know that [k]=[F]/[s]=[F]/L.

Newtons Second Law: F=ma thus, [F]=[m][a]=ML/T².

Therefore, [k]=M/T².

So then

[m^xk^y]=M^x*(M/T2)^y=M^(x+y)/T^2y

so, if this is to be equal to 1/T, we need to satisfy

x+y=0 and 2y =1

so x = -½ and y = ½.

Thus, we have shown that:

f a (k/m)^1/2 (that is, the frequency is proportional to the square root of the spring constant divided by the mass on the end of the spring).

In fact, I know that f is exactly equal to (k/m)^1/2, but the dimensional analysis technique cannot show that. For that, we need to use some calculus, which will be the subject of another article.

Friday, March 17, 2006

NASA - Ringside Seat to the Universe's First Split Second

Time Line of the Universe -- The expansion of the universe over most of it's history has been relatively gradual. The notion that a rapid period "inflation" preceded the Big Bang expansion was first put forth 25 years ago. The new WMAP observations favor specific inflation scenarios over other long held ideas. (credit NASA)

Ringside Seat to the Universe's First Split SecondYou don't get much closer to the big bang than this.Scientists peering back to the oldest light in the universe have evidence to support the concept of inflation, which poses that the universe expanded many trillion times its size faster than a snap of the fingers at the outset of the big bang.The expansion of the universe over most of it's history has been relatively gradual. The notion that a rapid period inflation preceded the Big Bang expansion was first put forth 25 years ago. The new WMAP observations favor specific inflation scenarios over other long held ideas. We're talking about when the universe was less than a trillionth of a trillionth of a second old. In that crucial split second, changes occurred that allowed for the creation of stars and galaxies hundreds of millions of years later.The new finding was made with NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and is based on three years of continuous observations of the cosmic microwave background, the afterglow light from the first moments of the universe.

News in Science - Frog croaks in ultrasound - 16/03/2006

A rare frog uses ultrasound to communicate, a clever tool that helps it overcome the noise of the waterfalls it lives in, researchers say.The concave-eared torrent frog (Amolops tormotus) is the first non-mammalian species known to use the ultra-high frequencies that humans cannot hear.It joins bats, dolphins and whales, and a small number of rodents, in the elite club of creatures that can communicate this way.

The Science Show: 11 March 2006 - Maths rules - proofs, Proof and Numb3rs

Saturday 11 March 2006

Summary

According to a mathematician at the American Association Meeting for the Advancement of Science, we've been living through a major revolution in mathematics spearheaded by a small group of mathematicians that deal in proof. But proof doesn't come easily or quickly and the process of verification can take almost as long. On the other hand, portraying serious mathematics on television is a challenge met weekly by Numb3rs, where advisors must condense problems which take years into information accessible to millions of views - in a one hour time slot. And Radio National's Alan Saunders looked at how mathematicians are portrayed in film.

Program Transcript

News Item: New York: A public school teacher was arrested today at John F Kennedy international airport as he attempted to board a flight while in possession of a ruler, a protractor, a set square, a slide rule and a calculator.

At a morning press conference Attorney General John Ashcroft said he believes the man is a member of the notorious Al-Gebra movement.He did not identify the man who is being charged by the FBI with carrying weapons of math instruction.

“Al-Gebra is a fearsome cult” Ashcroft said, “They desire average solutions by means and extremes and sometimes go off on tangents in a search of absolute value. They use secret code names like 'x' and 'y' and refer to themselves as 'unknowns', but we have determined they belong to a common denominator of the axis of mediaeval with co-ordinates in every country.

As the Greek philanderer Isosceles used to say, there are three sides to every triangle”.

When asked to comment on the arrest, President Bush said, “If God had wanted us to have better weapons of math instruction he would have given us more fingers and toes”.

Whitehouse aids told reporters they could not recall a more intelligent or profound statement by the President.

Robyn Williams: The film Proof opens in Australia next week - thoughts on that from Alan Saunders later on. The trouble with a mathematical proof is that it’s not straightforward. Not any more. No wonder mathematicians go bonkers. Here’s Keith Devlin.

Read more at www.abc.net.au/rn/scien...

Michigan State University Newsroom - Physics discovery: Nuclei still full of surprises, say MSU scientists

EAST LANSING, Mich. — Scientists at the National Superconducting Cyclotron Laboratory at Michigan State University have reproduced the processes inside stars in a laboratory to produce one isotope – Copper 57 – that revealed a mystery in one of its subatomic cousins, Nickel 56.The work has been accepted for publication in Physical Review Letters.Paul Mantica, a professor at the laboratory who specializes in nuclear chemistry, explained that in the quest for physicists to understand how the nucleus behaves, its standard operating procedure is to take what’s known and make assumptions about what must be true about unknowns.That’s where Nickel 56 – known as Ni-56 for short – comes in.Mantica and Kei Minamisono, a research associate, used nuclear magnetic resonance – a more sensitive relative of the magnetic resonance imaging used in medicine – to peer into the inner workings of elements. The magnetic resonance method is aided by polarizing the Cu-57 nuclei (assuring that they all “point” in the same direction) using a technique pioneered at MSU’s cyclotron laboratory. A measure of the magnetic nature of Cu-57 would then provide details about Ni-56.Scientists had hypothesized that Ni-56 should look a certain way.Ni-56 is what scientists call “doubly-magic.” That means that its number of protons and number of neutrons are in a subatomically tidy package that makes it more stable and easier to study.It’s like studying a bunch of cats and dogs. The groups are a lot easier to keep track of if they’re in a pen. That, basically, is what being doubly magic is – an isotope with the protons and neutrons in defined pens. The 28 protons and neutrons are more stable, and less likely to fall apart, when they’re penned up.Because Cu-57 is a close relative, scientists were betting its core should also be all neat and tidy. But Mantica said the experiment showed otherwise.“We found that the core is broken,” Mantica said. “It looks like it’s more open, like the double magic core is broken apart. Instead of solid core, we have a bunch of loose protons and neutrons.”And thus more work for physicists to do.

Thursday, March 16, 2006

Fine Tune Your Science Fair Topic

In order for your area of interest to lead to good project, you need go from a general topic to a specific question you can answer. If the specific question is not perfectly clear right now, that's alright – you just need to do a little more research (technically, research is the next step, but it's o.k. to mix these two together).

You will need to be sure that your question is not too general. It needs to be specific enough that you can research it and try to answer it with an experiment in the time you have.

Also, make sure that your question is hard enough that it is worth answering (that's not all that hard at all, really!), but not so hard that you cannot answer it. It is a good idea to get some feedback from your teacher or mentor at this point.

Your question should be open ended – not a simple yes or no question. A good science fair project (like good science) should lead to extended discussion, conclusions and more questions.

Also, make certain that you can answer your question without breaking any of the science fair's rules, like using dangerous materials or harming animals.

Research your topic

In this context, researching means finding out as much existing information on your topic/question as possible. This ensures that, not only will you be able to understand your topic well, but that you will be able to develop a question that will work for you. The more you understand at the end of this stage, the easier everything from here on will be.

Tips: Write down everything you already know about your topic in your notebook. Next to this list, write down all the questions you have and all the things you want to learn from the project. An important part of this list is “what you know that you don't know.” These lists will help you get started on your research, as the whole idea here is to find a series of bridges that take you from the first list to the second. Often, a number of bridges will be required – you will need to read books, talk to your teachers, search the Internet, contact scientists or other professionals involved in your topic, maybe read some technical or scientific journals and conduct an experiment.

For a science fair project, having an experiment is a critical part of the process. If you find yourself getting all the way there without an experiment, then you need to set your sights a little higher and add to your “want to know” list.

You should section off several (or many) pages of your notebook to organize all the information you gather. Remember to write down names, sources, pages, titles, website addresses and a summary of each chapter or article you read. Check with your teacher on the exact bibliography rules for your project.

Science Fair Project Schedule Checklist

Here is a list of tasks you'll need to work through with your project. Spread them out between now and the due date with intervals that make sense for you.

choose your topic
organize your notebook
ask organizational questions
research your chosen topic
define your problem
develop your hypothesis
design your experiment
Turn in an experiment summary to your teacher or mentor (if required, and even if it is not, I still recommend you discuss your experiment with someone)
Gather all the materials you need for your experiment
Start your experiment
Setup an outline for your project report
Collect materials for your display
Draft your project report
Design your display
Finish your experiment
Revise your experimental procedure and equipment list as needed
Analyze your data, drawing conclusions
Revise your project report
Complete your display
Edit and produce the final draft of your project report
Prepare for the fair!

This list is based upon the tasks you will need to cover for the typical science fair – you can, of course, add or subtract from this list as you want (and as your specific fair rules require).

Atoms in new state of matter behave like Three Musketeers: All for one, one for all

An international team of physicists has converted three normal atoms into a special new state of matter whose existence was proposed by Russian scientist Vitaly Efimov in 1970.In this new state of matter, any two of the three atoms--in this case cesium atoms-- repel one another in close proximity. "But when you put three of them together, it turns out that they attract and form a new state," said Cheng Chin, an Assistant Professor in Physics at the University of Chicago.

Wednesday, March 15, 2006

GLOBE at Night - Family Activity Packet

Students and families are encouraged to participate in a global campaign to observe and record the magnitude of visible stars as a means of measuring light pollution in a given location. Public contributions to an online database will document the visible nighttime sky during March 22-29, 2006. Students and families can learn how to locate the constellation Orion and that stars have different magnitudes of brightness in the night sky. This activity helps students and families understand how latitude and longitude coordinates provides a location system helping us to map and analyze the observation data submitted from all around the globe.As the campaign progresses, check this Web site to see the mapped results. Running totals will be displayed as the observation data is submitted. If you enjoyed this activity, your family may be interested in doing multiple observations by selecting a new location to enter a report. The new location should be at least 1 km away from your original observation location. Observations may be conducted and reported any time during 7:00-9:00pm local time and for any evening between March 22 and 29, 2006.

Unbalanced Superfluid Could Be Akin to Exotic Matter Found in Quark Star

Rice University physicist Randall Hulet will discuss breakthrough efforts to create a long-sought quantum superfluid at a press conference today[the 14th] at the American Physical Society's 2006 March Meeting.

Janus particles offer new physics, new technology

In Roman mythology, Janus was the god of change and transition, often portrayed with two faces gazing in opposite directions. At the University of Illinois at Urbana-Champaign, Janus particles are providing insight into the movement of molecules, and serving as the basis for new materials and sensors."By modifying the surface of colloidal particles into a Janus chemical compound, we can measure the rotational dynamics of single colloidal particles in suspension as well as at interfaces," said Steve Granick, a professor of materials science and engineering, chemistry and physics. "We can also take advantage of the particles' two very dissimilar sides to create families of microsensors."

Tuesday, March 14, 2006

Latest PhysicsWeb Summaries

News

Towards entangled-photon LEDs (Mar 6) http://physicsweb.org/article/news/10/3/4

Scientists in the UK have been able to generate pairs of entangled photons from a nanoscale crystal of semiconductor known as a "quantum dot" far more efficiently than was possible before. The breakthrough was made by Andrew Shields at Toshiba and colleagues at the University of
Cambridge, who produced entangled photons with an efficiency of 70% -- compared to a previous best figure of 49%. The improved performance approaches that required for useful applications, which means that devices emitting entangled light could one day be as common as lasers and light-emitting diodes (New J. Physics 8 29).

Antiproton co-discoverer dies (Mar 7) http://physicsweb.org/article/news/10/3/5

Owen Chamberlain, who co-discovered the antiproton with Emilio SegrÃ¨ in 1955, has died at the age of 85. Chamberlain and SegrÃ¨ shared the 1959 Nobel Prize for Physics for the discovery of the particle, which has the same mass as the proton, but opposite charge. Postulated by Paul Dirac in 1933, the antiproton is now routinely used in particle-physics experiments.

The oldest explosion in the universe (Mar 8) http://physicsweb.org/article/news/10/3/6

Astronomers have detected the most distant -- and therefore oldest -- gamma-ray burst ever. The burst, called GRB 050904, was observed last September and is thought to have come from an explosion that happened around 12.8 billion years ago, when the universe was just 7% of its
current age. The explosion released an intense flash of gamma rays that has been measured by three independent teams of astronomers from the US, Italy and Japan. The results -- reported in three papers in this week's Nature -- could help shed more light on the dynamics of the early
universe.

How to calculate hardness (Mar 9) http://physicsweb.org/article/news/10/3/7

When it comes to measuring the "hardness" of a material, most tests are distinctly low-tech and basically involve pressing a diamond tip into the surface and measuring the size of the dent produced. Now, however, physicists in the Czech Republic have developed a new way to predict the hardness of materials without going anywhere near a lab. The results, obtained from first-principles calculations alone, agree well with experimental data and could help scientists make harder materials (Phys. Rev. Lett. 96 085501).

Tiny motor turns giant rods (Mar 10) http://physicsweb.org/article/news/10/3/9

Researchers in the Netherlands have made a light-driven nano-scale motor that can rotate microscale objects that are 10,000 times bigger than itself. The motor consists of a molecule embedded in a liquid-crystalline film with a glass rod placed on top. As the molecule changes shape, it alters the structure of the film, which in turn makes the rod move (Nature 440 163).

Sunday, March 12, 2006

Researchers create conveyer belt for magnetic flux vortices in superconductors

Researchers create conveyer belt for magnetic flux vortices in superconductorsIf blown up in size, it would not have a chance in the car factory, but the microscopic conveyer belt built by Simon Bending's team in the Department of Physics at the University of Bath and collaborators in Japan and the USA, could just be the next big thing for improving devices relying on the elusive properties of superconductors (Nature Materials, Advanced Online Publication March 12 2006). It's not your standard rubber band on cylinders though – it moves in an erratic way, a quick jolt to the left, a smooth slide to the right. Who would want to be on such a thing?Tiny swirls of electric currents, it seems. These so-called vortices are the closest things to 'hurricanes' for the superconducting researcher and engineer, and no less threatening. That's because the zero resistance to current flow in even the best superconductors breaks down once vortices enter and start to move around. Their motion can also lead to unpredictable 'noise' if it takes place near the most sensitive regions of superconducting devices. Bending has now shown that it is possible to move vortices around inside a superconductor almost at will using his shaky conveyer belt. In this way they can either be removed entirely or at least left where they cause the least harm.The asymmetry in its movement is the key to success, since it ensures that the vortices all move in one direction, even though the belt itself moves back and forth. The reason behind this is that the vortices can only follow along during the smooth slides to the right, and not during the jolts in the other direction. The conveyer belt thus acts in some sense as a rectifier, just like the diodes known from electronics.The mind-boggling part is now that the conveyer belt is assembled out of a line of vortices itself, created and controlled by a time-varying magnetic field. As the researchers show, this way "bad" vortices can be completely removed out of targeted regions inside the superconductor, and the vortices induced to create the conveyer belt can be readily removed from the sample afterwards if need be.Using this trick, superconducting devices, such as filters for telecommunications or ultra-sensitive magnetic field probes, could be improved by removing vortices - naturally caused by the earth's magnetic field or man-made disturbances – from regions critical to device operation.###Bending's team consisted of fellow researcher David Cole, and theoretical collaborators Sergey Savel'ev and Franco Nori from RIKEN (Japan) and the Universities of Michigan and Loughborough, as well as scientists from the Universities of Tokyo and Manchester.

From www.eurekalert.org/pub_...

Saturday, March 11, 2006

The Physics of Friendship

By comparing people to mobile particles randomly bouncing off each other, scientists have developed a new model for social networks. The model fits with empirical data to naturally reproduce the community structure, clustering and evolution of general acquaintances and even sexual contacts.

In this visualization of a high school’s empirical friendship network from the scientists’ data, the different colored (blue, green, purple, orange) nodes represent students in different grades. Links between nodes are drawn when a student nominates another student as a friend. In the recent study, physicists developed a novel model to describe this social network based on rules governing physical systems. Credit: Marta Gonzalez

Friday, March 10, 2006

Physics 101 - Basic, Introductory Information about physics.

Physics 101 - Basic, Introductory Information about physics.

Physics 101: Introduction to Physics and Physicists
Physics is, sadly, not well understood. Few people know what physics is, or what physicists actually do. I have put together this page to answer some of the most common questions about physics.

What is Physics?
What is physics all about? What do physicists and physics students study?

Why Do We Study Physics?
Why do we study physics?

What are the Various Fields Within Physics?
What are the various subfields within physics? What sort of specific things do physicists study?

What do Physicists Actually Do?
What do physicists actually do? How do they spend their time - what are they doing in their offices all the time?

Why should I have to study physics if I'm going to be a ... ?
Short answer: Physics is cool, but I'm biased. Longer answer: Physics, as a discipline - especially at an undergraduate level, teaches many things that are important in all walks of life

Understanding and Using the Scientific Method
The scientific method is a process that scientists developed to form and answer questions. The scientific method arose mostly in the 17th and 18th centuries. This was a period of great scientific revolution in England and Europe, the era of Copernicus, Kepler, Galileo, Hooke, Leibniz, Halley, Newton and Young.

How To Create a Great (Physics) Science Fair Project
To do well in a science fair, you need to do two things – You need to not only demonstrate knowledge of science, but also knowledge of the process of science. It is really not that difficult, especially if you follow a system that will help you cover all your bases and makes sure that you learn everything you need to learn.

Q. Why should I have to study physics if I'm going to be a doctor - lawyer - etc?

Short answer: Physics is cool, but I'm biased.

Longer answer: Physics, as a discipline - especially at an undergraduate level, teaches many things that are important in all walks of life:

1) Problem Solving skills - the typical physics course is more problem solving based than any other subject (except perhaps mathematics) and the problems are often more practical. If you want to be a doctor, say, skill at quickly thinking about the problems of "what is wrong with this patient" could mean the difference between life and death.

2) Real World Familiarity - Freshman physics courses tend to teach about the every-day, real, world. You learn about how things move, how they fall, what friction means, what constraints conservation of energy and momentum can put on a system.
Imagine you're now a lawyer, defending an innocent man accused of a murder. What if the prosecution's theory of the crime had a small, but telling flaw in the physics - a problem with the trajectory of a bullet say - pointing this out convincingly would make your case trivial. Of course you would get an expert witness in to testify, but how would you know there was a potential hole there if you hadn't honed your physics intuition? And how will you interpret the physicist's testimony for the jurours if you dont understand any of it?

3) Relevant information - Physics is directly relevant to the core of many fields which might seem seperate at first glance. Engineers build bridges, but they need to understand the forces involved and how bridges react to stress in order to build safe ones. Biologists look at proteins and DNA - the structures of which are measured using diffraction techniques developed by physicists, and only really understood through physics. Biologists also use light and lasers to make flourescence measurements to keep track of the chemicals present - physics illuminates (if you'll pardon the pun) the devices, lenses, microscopes and the very colors of the dies used!

As you can see, there are many good reasons to study physics, no matter what your career goal might be - but the most important is that physics is constantly unveiling new facts about our universe - from the very small, like new semiconductors and superconductors, to the very large, like black holes and galaxies - do you want to understand what is coming, or do you want to be left behind?

What Do Physicists Actually Do?

Physicists do all sorts of things.

For every subfield of physics, there are physicists who focus on the problems with those fields. Some physicists try to identify the basic principles governing the universe of matter and energy – the structures, behavior, generation, transfer, motion and interactions that underlie the phenomena of reality, while others explore the higher level effects of these principles, working towards more "practical" goals – developing better materials and more useful devices. Across this spectrum, there are physicists working with all possible degrees of "application" from abstract research that is virtually pure mathematics to very applied technology research that is barely distinguishable from engineering.

Typically physicist's interests and work are defined by two choices: their field and whether they choose to pursue experimental or theoretical research. Most physicists concentrate on a single field, one of the many subfields from: Acoustics, astronomy astrophysics, atomic physics, biophysics, chaos, chemical physics, computational physics, cosmology, crystallography, electromagnetism, electronics, fluid dynamics, general relativity, geophysics, high energy physics, high pressure physics, laser physics, light physics, low temperature physics/cryophysics/cryogenics, mathematical physics, mechanics, meteorology/weather physics, molecular physics, nanotechnology, nuclear physics, optics, particle physics, plasma physics, quantum physics, quantum optics, quantum field theory, quantum gravity, statistical mechanics, string theory and thermodynamics.

While many physicists will remain in the same field throughout their careers, just as many work in a number of areas – following their interests as they evolve with time.

Normally, physicists further specialize in the experiments or the theory related to those problems (Enrico Fermi, one of the great minds of Nuclear Physics is the last physicist to be generally acknowledged to be a master of both experiments and theory). These two types of physicist – the theoretician and the experimentalist have many differences and commonalities.

The theoreticians work with pencil and paper (or, more recently with keyboard and mathematics software), working through the physics of the phenomena they are interested in from the equations.

The experimentalists perform another crucial task: They seek to confirm or contradict the theories of physics through comparison with actual results. Detailed, arduous experiments are often required to explore the details of theories at the forefront of physics, sometimes requiring very large teams of researchers working with multimillion dollar apparatus (especially in the field of high energy physics).

While research is the core of the typical physicist's job, most will have to take teaching work as part of their positions, instructing potential new physicists (and other students who need to take physics for various reasons – like getting into medical school) in the facts of the universe. In addition to teaching classes, they usually have research students – typical graduate and postdoctoral students who are essentially apprenticed to the professor, learning the details of their specific fields as they help with their supervisor's research, gaining more independence in their research as their experience progresses.

Most of all, physicists follow their natural curiosity and interests as they explore the ways of the universe.

What are the Various Fields Within Physics

What sort of specific things do physicists study?

Physics incorporates many subfields, including (but not limited to):

Acoustics
Astronomy
Astrophysics
Atomic Physics
Biophysics
Chaos
Chemical Physics
Computational Physics
Cosmology
Crystallography
Electromagnetism
Electronics
Fluid Dynamics
General Relativity
Geophysics
High Energy Physics
High Pressure Physics
Laser Physics
Light Physics
Low Temperature physics/Cryophysics/Cryogenics
Mathematical Physics
Mechanics
Meteorology/Weather Physics
Molecular Physics
Nanotechnology
Nuclear Physics
Optics
Particle Physics
Plasma Physics
Quantum Physics
Quantum Optics
Quantum Field Theory
Quantum Gravity
Statistical Mechanics
String Theory - Superstring Theory
Thermodynamics

Most of these fields have both experimental and theoretical sides - few physicists these days do both experimental and theoretical physics.

The last physicists to truly excel at both sides of the science was Enrico Fermi.

Amongst the purely physics fields listed above, you will notice fields like geophysics, biophysics and chemical physics where physics research has expanded into fields that are traditionally thought of as separate (geology, biology and chemistry). Physicists bring to these fields the tools and methodology of physics, which often allows new solutions to problems experienced in the original field to be solved with tools that were originally created to solve physics problems.

In a nutshell, physicists study whatever is interesting to them. Physicists are as often found studying things that would seem far afield from "physics" as they are found doing "typical" physics experiments.