Dec 24 2010
I am starting to worry about how we teach Physics to the pupils of today. It seems increasingly obvious that we teach more and more about things that are really unimportant to science and less about the fundamentals.
For example we spent a lot of time on the new HSW curriculum on identifying the type of a variable i.e. categorical, continuous and similar. This allows the pupils to decide which graph type to draw in an ISA exam for AQA and similar boards. However, really is that a skill that they need in their everyday lives or society needs for scientists of the future?
Now try some of these video cartoon clips https://www.animatedscience.co.uk/flv/ from KOCE (also see list on that page).
When you start to think about it, why is school Physics not split like this for all pupils into five main sections. Then just look at the topics they are such simple fundamental things which everyone should know about for their everyday lives. Also the right way to teach for pupils who go onto to Uni and further!
How many pupils really know about how a wheel works or simple lever, possibly mans greatest inventions. However, somehow written out by the QCA from KS3 and KS4. On the select few who take A-Level Physics are supposed to learn about these basic things of life?
Even more interestingly to really see if school science has failed is ask these question to a pupil. “What do stars do”. They will all answer “emit light”. Then you refine it…. “apart from emit light” which is obviously a secondary thing. Then 99% will not know and neither will most adults either. So in fact it seems the people who write the GCSE Physics for the nation as the missed it out of all the specs.
Stars in fact create all the elements in the Universe and of course those which make up our bodies. So what do we teach about stars…. well we teach about life and death cycles but forget the major important thing.
So what am I saying? Well if you can please slip into your teaching some of the really important things which will still give us pupils who can think for themselves and be creative. Also make sure that every pupil who goes through your hands regardless of if the QCA tells you to teach it or not understands the idea of a lever!
Permanent link to this article: https://animatedscience.co.uk/2010/the-problem-with-teaching-physics-in-modern-times
Dec 24 2010
In the prototype, sunlight heats a ceria cylinder which breaks down water or carbon dioxide
The machine uses the Sun’s rays and a metal oxide called ceria to break down carbon dioxide or water into fuels which can be stored and transported.
Conventional photovoltaic panels must use the electricity they generate in situ, and cannot deliver power at night.
The prototype, which was devised by researchers in the US and Switzerland, uses a quartz window and cavity to concentrate sunlight into a cylinder lined with cerium oxide, also known as ceria.
Ceria has a natural propensity to exhale oxygen as it heats up and inhale it as it cools down.
If as in the prototype, carbon dioxide and/or water are pumped into the vessel, the ceria will rapidly strip the oxygen from them as it cools, creating hydrogen and/or carbon monoxide.
Hydrogen produced could be used to fuel hydrogen fuel cells in cars, for example, while a combination of hydrogen and carbon monoxide can be used to create “syngas” for fuel.
It is this harnessing of ceria’s properties in the solar reactor which represents the major breakthrough, say the inventors of the device. They also say the metal is readily available, being the most abundant of the “rare-earth” metals.
Methane can be produced using the same machine, they say. Refinements needed The prototype is grossly inefficient, the fuel created harnessing only between 0.7% and 0.8% of the solar energy taken into the vessel. Most of the energy is lost through heat loss through the reactor’s wall or through the re-radiation of sunlight back through the device’s aperture. But the researchers are confident that efficiency rates of up to 19% can be achieved through better insulation and smaller apertures. Such efficiency rates, they say, could make for a viable commercial device. “The chemistry of the material is really well suited to this process,” says Professor Sossina Haile of the California Institute of Technology (Caltech). “This is the first demonstration of doing the full shebang, running it under (light) photons in a reactor.”
She says the reactor could be used to create transportation fuels or be adopted in large-scale energy plants, where solar-sourced power could be available throughout the day and night. However, she admits the fate of this and other devices in development is tied to whether states adopt a low-carbon policy. “It’s very much tied to policy. If we had a carbon policy, something like this would move forward a lot more quickly,” she told the BBC. It has been suggested that the device mimics plants, which also use carbon dioxide, water and sunlight to create energy as part of the process of photosynthesis. But Professor Haile thinks the analogy is over-simplistic.
“Yes, the reactor takes in sunlight, we take in carbon dioxide and water and we produce a chemical compound, so in the most generic sense there are these similarities, but I think that’s pretty much where the analogy ends.”
Daniel Davies, chief technology officer at the British photovoltaic company Solar Century, said the research was “very exciting”.
“I guess the question is where you locate it – would you put your solar collector on a roof or would it be better off as a big industrial concern in the Sahara and then shipping the liquid fuel?” he said.
Solar technology is moving forward apace but the overriding challenges remain ones of efficiency, economy and storage.
New-generation “solar tower” plants have been built in Spain and the United States which use an array of mirrors to concentrate sunlight onto tower-mounted receivers which drive steam turbines.
A new Spanish project will use molten salts to store heat from the Sun for up to 15 hours, so that the plant could potentially operate through the night.
Permanent link to this article: https://animatedscience.co.uk/2010/new-solar-fuel-machine-mimics-plant-life
Dec 01 2010
3-D invisibility cloak hides gold “bump” The first device to hide an object in three dimensions has been unveiled by a group of physicists in the UK and Germany. While the design only cloaks micro-scale objects from near-infrared wavelengths, the researchers claim that there is nothing in principle to prevent their design from being scaled up to hide much larger artefacts from visible light. The origins of this design date back to 2006, when David Smith and colleagues at Duke University in North Carolina created a cloak that could bend microwaves around an object, like water flowing around a smooth stone.
This early cloak was made using a metamaterial – an artificially constructed material with unusual electromagnetic or other properties – which consisted of a cylinder built up from concentric rings of copper split-ring resonators. This first cloak, however, only worked in two dimensions – in other words, looking at the cylinder from above revealed the presence of the shielded object.
Carpet cloak Now Tolga Ergin and colleagues at Karlsruhe Institute of Technology in Germany, together with John Pendry of Imperial College in London, have overcome this problem by creating a “carpet cloak”. Proposed in 2008 by Pendry and Jensen Li, this involves hiding an object underneath a bump on the surface of an otherwise smooth material – just as something might be hidden under a carpet – and then smoothing out the resulting bump. This is achieved by creating a bump on a flat mirror and then placing onto the mirror a layer of metamaterial with optical properties such that light appears to reflect off the mirror as if the bump were not there. This technique was demonstrated experimentally at two different wavelengths last year, with Smith’s group showing that it worked in the microwave region while researchers at Berkeley and Cornell University near New York obtained similar results at infrared wavelengths. However, these cloaks were also limited to just two dimensions.
Ergin’s group has made a carpet cloak in three dimensions by stacking nanofabricated silicon wafers on top of one another in a “woodpile” matrix and then filling in the gaps between the wafers with varying amounts of polymer. This achieves the desired distribution of refractive indices within the structure. Hiding the bump The cloak structure was then placed on top of a reflective gold surface containing a bump, leading to a cloaking effect using unpolarized light with wavelengths between 1.4 and 2.7 µm – the near-infrared. Importantly, this effect held for viewing angles up to 60 degrees (with zero degrees representing viewing in just two dimensions).
The bump, however, was very small – just 30 µm (10–6 m) × 10 µm × 1 µm. Team member Martin Wegener says it should be possible to use existing technology to make the cloak bigger in order to hide larger objects, but that this approach would be extremely time-consuming. “Faster nanofabrication tools will have to be developed allowing for three-dimensional structures,” he adds. For Wegener the aim of the work is not about focusing all efforts on creating invisibility cloaks, but is about exploring a range of applications in transformation optics.
This involves calculating what kind of material is needed to bend light in a certain way, by considering light trajectories as the result of the warping of space. Wegener says that transformation optics should lead, for example, to the design of better antennas or smaller optical resonators. Smith describes the latest work as “very exciting” and agrees that its real importance lies in the development of transformation optics. “Demonstrations like these are paving the way for transformation optical design to become an established design methodology, like ray-tracing,” he says. The research is published in Science.
Permanent link to this article: https://animatedscience.co.uk/2010/3d-invisibility-cloak-unveiled
Nov 15 2010
WASHINGTON — Astronomers using NASA’s Chandra X-ray Observatory have found evidence of the youngest black hole known to exist in our cosmic neighborhood. The 30-year-old black hole provides a unique opportunity to watch this type of object develop from infancy.
The black hole could help scientists better understand how massive stars explode, which ones leave behind black holes or neutron stars, and the number of black holes in our galaxy and others.
The 30-year-old object is a remnant of SN 1979C, a supernova in the galaxy M100 approximately 50 million light years from Earth. Data from Chandra, NASA’s Swift satellite, the European Space Agency’s XMM-Newton and the German ROSAT observatory revealed a bright source of X-rays that has remained steady during observation from 1995 to 2007. This suggests the object is a black hole being fed either by material falling into it from the supernova or a binary companion.
“If our interpretation is correct, this is the nearest example where the birth of a black hole has been observed,” said Daniel Patnaude of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. who led the study.
The scientists think SN 1979C, first discovered by an amateur astronomer in 1979, formed when a star about 20 times more massive than the sun collapsed. Many new black holes in the distant universe previously have been detected in the form of gamma-ray bursts (GRBs).
However, SN 1979C is different because it is much closer and belongs to a class of supernovas unlikely to be associated with a GRB. Theory predicts most black holes in the universe should form when the core of a star collapses and a GRB is not produced.
“This may be the first time the common way of making a black hole has been observed,” said co-author Abraham Loeb, also of the Harvard-Smithsonian Center for Astrophysics. “However, it is very difficult to detect this type of black hole birth because decades of X-ray observations are needed to make the case.”
The idea of a black hole with an observed age of only about 30 years is consistent with recent theoretical work. In 2005, a theory was presented that the bright optical light of this supernova was powered by a jet from a black hole that was unable to penetrate the hydrogen envelope of the star to form a GRB. The results seen in the observations of SN 1979C fit this theory very well.
Although the evidence points to a newly formed black hole in SN 1979C, another intriguing possibility is that a young, rapidly spinning neutron star with a powerful wind of high energy particles could be responsible for the X-ray emission. This would make the object in SN 1979C the youngest and brightest example of such a “pulsar wind nebula” and the youngest known neutron star. The Crab pulsar, the best-known example of a bright pulsar wind nebula, is about 950 years old.
“It’s very rewarding to see how the commitment of some of the most advanced telescopes in space, like Chandra, can help complete the story,” said Jon Morse, head of the Astrophysics Division at NASA’s Science Mission Directorate.
The results will appear in the New Astronomy journal in a paper by Patnaude, Loeb, and Christine Jones of the Harvard-Smithsonian Center for Astrophysics. NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for the agency’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge.
For more information about Chandra, including images and other multimedia, visit:
Permanent link to this article: https://animatedscience.co.uk/2010/nasas-chandra-finds-youngest-nearby-black-hole
Nov 12 2010
Have some fun label the diagram….
Permanent link to this article: https://animatedscience.co.uk/2010/structure-of-a-leaf-ks45-biology
Permanent link to this article: https://animatedscience.co.uk/2010/screen-saver