Physics News from the AIP No 2, Term 1 2005



Physics News from the AIP Term 4, No 5, 2008

Table of Contents

1. National Curriculum Update

2. WGBH Teachers’ Domain

3. Astounding Astrophotographs

4. Forthcoming events for Students and the General Public

a)* Astronomical Art by Prof Jocelyn Bell Burnell at University of Melbourne, 6:30pm Monday 8th December

b) VCE Physics Days at Luna Park in 2009

5. Forthcoming events for Teachers

a) From Einstein's intuition to quantum bits: a new quantum age? 6.30pm Weds 10 Dec, University of Melbourne

b)* Acoustics from the Musician’s Perspective. Ballarat, 11am, 16th January, 2009

c)* 2009 Physics Teachers Conference, Monday 16th February, 2009

6. Physics News from the Web

a) Leader of the Pack. A new study shows why it’s sometimes better to stay out front.

b) What President-Elect Obama Needs To Know About Physics. (Quiz included)

c) Using Sunlight More Efficiently

*For details of items 4a, 5b and 5c you can check the previous email newsletters or go to the Forthcoming Events page of our website . The previous emails can also be accessed at News section of our website

This newsletter is compiled by the Australian Institute of Physics (Victorian Branch) Education Committee. Check our website for latest resources, events and forum discussions. A list of over 90 items from previous editions of “Physics News from the AIP” that are still of value can be found in the “News” section of the website, as can all the news stories from the item “Physics News from the Web”.

This year the AIP Education Committee meets at Camberwell High School normally on the second Tuesday of the month from 5pm – 7pm, the date of the next meeting is 9th December. If you would like to attend this or any other meeting, please contact the chair, Sue Grant at susanmgrant@.au

1. National Curriculum Update

Framing papers for English, Maths, Science and History are now available on their website and comment is sought by 28th February 2009. The document is 12 pages long with a detailed 6 page survey form in the appendices.

The document discusses the following matters: Selection of science content, Relevance of science learning, Flexibility and equity, General capabilities, and under the Structure of the curriculum, the Elements of a science curriculum and an outline for the different Stages of schooling, specifically stage 1 (typically from 5 to 8 years of age), stage 2 (typically from 8 to 12 years of age), stage 3 (typically from 12 to 15 years of age) and stage 4 (typically from 15 to 18 years of age).

Feedback can be emailed to feedback@.au and written feedback can be mailed to: National Curriculum Board, Feedback, PO Box 177, Carlton South, Victoria 3053. Online feedback can be submitted through . You can register from this link. Once you have joined, a username and password provide access to online surveys, discussions and summaries of feedback comments. This is an opportunity to be fully involved and up-to-date with national curriculum development.

Earlier this term there was a briefing for Science teachers on the National Science Curriculum. One key item of information was that the National Curriculum is not likely to be implemented at Year 12 until 2012 and possibly 2013.

2. WGBH Teachers’ Domain

WGBH is a public service media organisation based in Boston, New England, USA. It produces material for TV, radio, the Web, and out in the community. Its motto is “Produced in Boston, shared with the World”. Its ‘Teachers’ Domain’ contains more than 1000 classroom ready multimedia resources for K - 12 teachers. Free registration is required, but up to 7 free downloads are available without registration.

The address for Science section is:

Under Science there are sections for Earth and Space Science, Engineering, Life Science and Physical Science. Each of these has 3 to 6 sub-categories. Sub-categories linked to Physics are:

Physical Science

|Sub-category |Physics related Topics |

| |with the number of relevant resources in brackets |

|Energy |Energy Sources (40) |

| |Heat (6) |

| |Light (36) |

| |Nuclei and Radiation (13) |

| |Radio Waves (17) |

| |Sound Waves (30) |

| |Work and Simple Machines (3) |

|Fundamental Theory |Cosmology and Gravity (25) |

| |Quantum Mechanics (12) |

| |String Theory (11) |

| |Special Theory of Relativity (13) |

|Matter |The Atom (11) |

| |The Atomic Basis of properties of matter (71) |

| |Atomic Nucleus (33) |

| |Cosmology (28) |

| |Properties of matter (40) |

|Motion and Forces |Electricity and Magnetism (20) |

| |Forces between Objects (20) |

| |Gravity (36) |

| |Objects in Motion (36) |

| |Pushes and Pulls (16) |

| |Tension and Compression (24) |

| |Velocity and Acceleration (20) |

Engineering has the topic of ‘Materials and Tools’ with 10 resources.

The multimedia resources are mainly QuickTime video, or Flash or HTML interactives.

Each resource has a Background Essay describing the content, Discussion Questions and an indication of level. The activities are designated as covering a wide age range, e.g 3 - 8, 3 - 12, 6 - 12, etc, so the information provided needs to be read to identify whether it suits your purpose. The number in brackets above is the number that include Year 12 in the range.

Each section also has a small set of very detailed lesson plans that incorporate some of the resources.

3. Astounding Astrophotographs

The two people who designed our website, Neil Creek and Phil Hart, who is also the son of Christina Hart, are both successful astrophotographers. An amazing set of 10 photos by Phil are on display at the website: . Neil also had an impressive photograph published in Discover magazine

4. Forthcoming events for Students and General Public

*For details of items 4a you can check the previous email newsletters or go to the Forthcoming Events page of our website . The previous emails can also be accessed at News section of our website

b) VCE Physics Days at Luna Park in 2009

The VCE Physics Days next year are Tuesday 3rd Wednesday 4th and Thursday 5th of March. To make a reservation contact Luna Park by phone on (03) 9525 5033 or fax to (03) 9534 5764, or mail to Luna Park at PO Box 1083, St Kilda South, Victoria, 3182. A confirming deposit will be required by the Friday 13th Feb. The cost of the day is unchanged at $20.95 per student, with teachers free. Our website, lunapark.html has details of the worksheets and arrangements for each of the days.

5. Forthcoming events for Teachers

*For details of items 5b and 5c you can check the previous email newsletters or go to the Forthcoming Events page of our website . The previous emails can also be accessed at News section of our website

a) From Einstein's intuition to quantum bits: a new quantum age?

Alain Aspect, CNRS Senior Scientist at Institut d'Optique and Professor at Ecole Polytechnique, Palaiseau

6.30pm Wednesday 10 December, 2008, Theatre A, Elisabeth Murdoch Building, University of Melbourne, refreshments will be available in the foyer from 5.30pm.

In 1935, with co-authors Podolsky and Rosen, Einstein discovered an amazing quantum situation, where particles in a pair are so strongly correlated that Schrödinger called them "entangled". By analyzing that situation, Einstein concluded that the quantum formalism was incomplete. Niels Bohr immediately opposed that conclusion, and the debate lasted until the death of these two giants of physics, in the 1950s.

In 1964, John Bell produced his famous inequalities which would allow experimentalists to settle the debate, and to show that the revolutionary concept of entanglement is indeed a reality. Based on that concept, a new field of research has emerged, quantum information, where one uses entanglement between qubits to develop conceptually new methods for processing and transmitting information. Large scale practical implementation of such concepts might revolutionize our society, as did the laser, the transistor and integrated circuits, some of the most striking fruits of the first quantum revolution, which began with the 20th century.

6. Physics News from the Web

Items selected from the bulletins of the IOP and the American Institute of Physics.

a) Leader of The Pack. A new study shows why it’s sometimes better to stay out front.

b) What President-Elect Obama Needs To Know About Physics. Quiz included , see below

c) Using Sunlight More Efficiently

a) LEADER OF THE PACK. A new study shows why it’s sometimes better to stay out front.

Lance Armstrong, the cyclist who won the Tour de France six times, often came in first because he spent so much time in second. That is, he would regularly pedal right behind a teammate whose job was to obligingly break up the stream of oncoming air, making it easier for Armstrong to save his own energy for a sprint later on. Stock cars also often maneuver to be in the draft of the car in front, thus reducing drag. A new study, however, suggests that this strategy of staying right behind a leader can backfire.

Bikes and stock cars are rigid bodies which cast a definite wind shadow. But if the object out front is a flapping body, such as a wiggling fish, a waving flag, or a bird beating its wings, then the disturbed flow set up by the flapping can increase, rather than decrease, aerodynamic drag for the follower. Not only does the follower experience more drag---forcing him to expend more energy go keep up---but the leader feels less drag.

This hypothesis is difficult to test on living animals such as birds or fish so two scientists performed an experiment with tiny waving flags. Leif Ristroph of Cornell University and Jun Zhang at New York University used two flags. Instead of a stream of air they used a flowing soap film that allowed clear images to be taken of the complex patterns set up when the fluid comes past the flags.

The result was surprising. Not only was the drag for the following flag made worse by the swirling fluid, but the measured drag felt by the leader was reduced, by as much as 50 percent, below the drag it feels when it is by itself. This is because the commotion set up by the following flag can mitigate the drag felt by the leader.

Jhang says that it’s too early to confirm that for some animals-such as migrating birds and schools of fish-being the leader of the pack is better because it reduces the energy needed to counteract drag. So far the experiment has been carried out with two flags and with six flags, and Jhang and his colleague would like to study their ideas with real animals. He believes that his results might have industrial applications, where reducing energy input is almost always a good thing.

b) WHAT PRESIDENT-ELECT OBAMA NEEDS TO KNOW ABOUT PHYSICS. Nuclear and biological terrorism, energy, and climate are among the top topics. Quiz included , see below

Even scientists can hardly keep up with the influx of new research discoveries. So how can the president of the United States, with a blizzard of issues to deal with daily, expect to stay informed on scientific and technological developments that have an impact on society? Richard A. Muller, a professor at the University of California at Berkeley, addresses this problem in his new book, "Physics for Future Presidents." The book is divided into five large topic areas which essentially define the hottest issues of today: terrorism, energy, nukes, space, and global warming. Muller believes that anyone who strives to be a world leader needs to possess a core of knowledge in these areas.

Muller's book is based on a course he's been teaching at Berkeley for years, so he's had plenty of time to think about what the world leader needs to know---at least that part of knowledge pertaining to the material world. Voted the best course on campus, Muller's class, "Physics for Future Presidents" uses no equations or detailed mathematical description. Instead it imparts a commonsense, but accurate, appreciation of certain technological hazards and opportunities.

For example, Muller believes the president should know about radiation levels (it's the accumulative dose that is medically important), about the difference between nuclear fission and fusion explosions (the latter are much more powerful), about the relative energy content of various substances (gasoline, and even cookies, have more energy per weight than TNT), and about the relative cost of electricity obtained from batteries used in cell phones, computers, and automobiles. The president must be able to intelligently absorb information about the impact of human technology on climate, and to know that no single unexpectedly hot or cold day denotes a significant indicator of things to come.

The president can't afford to learn about such things as the danger from radiation at the last minute, argues Muller, because in certain circumstances, every second counts. Consider, for example, the detonation of a dirty bomb, in which an ordinary (non-nuclear) explosion spreads radioactive materials. Fatalities, property damage, and even residual radiation, would likely be very small. "The biggest danger from a radiological weapon is the misplaced panic and overreaction that it would cause. A dirty bomb is not really a weapon of mass destruction, but it is potentially a weapon of mass disruption," Muller says. Allocating resources during a crisis---military, medical, emergency, and engineering---requires quick and shrewd thinking.

Muller views physics as the "liberal arts of high technology," insofar as physicists are trained to solve problems in a broad category of topics, many of them relating to the very topics---such as energy and nuclear issues---that form the backdrop to numerous national-security concerns. This is probably why so many presidential science advisors have been physicists.

Science advisors have been losing the clout they once had, Muller believes, because they---and scientists in general---are perceived as a special-interest group, with their goal being greater federal support for science. A good presidential science advisor, Muller argues ironically, should not do all that much advising. Instead she or he should act as an early alert system informing or educating (but not lobbying) the president on science and technology issues and their possible impact.

Muller has extensive experience on rendering government-requested science advice. For many years he was a member of the "Jasons," an organization of leading scientists who meet for a month or more each summer to study specific subjects---most of them relating to national security---of interest to the Pentagon or other federal agencies. This work, Muller says, taught him the value of asking lots of dumb questions and of not necessarily trusting all the things he was told by experts.

Test your own presidential science knowledge. Nature magazine featured a set of questions from Muller's class on its website: news/specials/climatepolitics/index.html

C) Using Sunlight More Efficiently

Researchers at the National Renewable Energy Laboratory (NREL) in Golden, Colorado have developed a way for low-cost solar cells to more efficiently convert sunlight into electricity. The research, which increases the "lifetime" of electrons created in a solar cell so they can make more electricity, is a possible step in the direction of bringing down the relatively high cost of solar cells. Reducing cost while sustaining efficiency is the big factor in determining how soon solar power will become a major player in the energy business. Generally you could have good efficiency or low cost but not both. Efficiency refers to the fraction of the sunlight falling on the solar panel that actually gets converted into useable electricity. And cost refers to the expense of mass-producing the panels in large sheets. Solar cells have been used in niche markets, such as for powering remote sensors or spacecraft, and are increasingly used for homes and utility applications.

Most of these solar cells are made from crystalline silicon. But for large-scale adoption to occur, the price will have to come down. Currently the cost-per-kilowatt-hour for solar-generated power is several times higher than for generating that power with fossil fuels. Solar cells mimic nature in the way that it converts sunlight into useful energy. In a green leaf, for example, the incoming sunlight liberates an electron in a molecule of chlorophyll. The electron (and its energy) gets passed from one molecule, eventually being incorporated into building up larger molecules such as a carbohydrate. In a solar cell the incoming sunlight liberates an electron from a piece of semiconductor. This "excited" electron, if it stays excited, can be incorporated into an electrical current feeding into an external circuit, where it can flow into a battery or the electric grid. The longer the lifetime of the excited electron, the better the efficiency of the solar cell. Unfortunately, electrons tend to lose their energy when they meet a defect or boundary in the crystals that make up a solar cell. Until now to get a better excitation lifetime and better efficiency, solar cells needed to be made of higher-priced single crystal materials like silicon or gallium arsenide. These solar cells need lots of complex processing to build, and these costs are not likely to be reduced. Meanwhile, lower-priced solar cells made from thin layers of multi-crystalline materials, such as compounds made of the atoms copper, indium, gallium, and selenium (CIGS), haven't been nearly as efficient.

The research focused on improving electron lifetimes in solar cells made from multi-crystalline CIGS, and in their research paper, NREL scientists Wyatt Metzger, Ingrid Repins, and Miguel Contreras announced they have achieved an electron lifetime of 250 billionths of a second. It sounds like a short time, but it is long enough for more electrons to contribute to the cell's electricity, making it dramatically more efficient, yet still low in cost when compared to the high-efficiency silicon solar cells.

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