Dec 15, 2015 07:50 PM
(This post was last modified: Dec 16, 2015 07:51 PM by C C.)
Killing a physical theory softly - roulette style
http://www.theguardian.com/science/life-...ette-style
EXCERPT: What is ‘scientific progress’? What does it mean? How is it achieved? Cleary, one avenue is improving our experiments, measuring effects more precisely and developing new experiments which shed light on previously uncharted realms of Nature. But what do we learn from these measurements? Do we verify a scientific theory? Not exactly. The statement “All swans are white.” can not be verified, unless you are certain you have checked every single swan.
Historically, Newtonian mechanics and gravity were the prevailing theory of Nature, supported by all measurements for over 200 years. It was very successful, but not verified. [...] Around 1900, the situation changed dramatically [...] These results falsified Newton’s theory. Black swans had been found! Einstein’s special and general theory of relativity replaced it as a better - but not necessarily true - theory [...]
[...] the Higgs Boson discovered at the LHC in 2012. It was predicted by the Standard Model of elementary particle physics, developed more than 40 years earlier. [...] However, this does not mean that the Standard Model is true? The answer is an emphatic “no”, as we already have a new black swan: dark matter. [...] So why do we still use the Standard Model? Because, annoyingly, it just describe every other measurement so well – and, to be honest, because we haven’t found the new encompassing theory yet. Or have we?
Enter: supersymmetry. [...] if we measure the processes at the LHC precisely enough, we might be able to distinguish supersymmetry from the Standard Model. Alternatively, we could try to falsify supersymmetry, but how? Our proposal is to do it the soft way....
Vacuum Energy
http://physics.about.com/od/physicsutoz/...Energy.htm
EXCERPT: Vacuum energy is the energy created by empty space by the constant creation and destruction of particles by the quantum fields that fill the universe....
Physics for the mechanism of slow change in microscopic magnetic structures revealed
http://www.sciencedaily.com/releases/201...105305.htm
The research group of Professor Hideo Ohno and Associate Professor Shunsuke Fukami of Tohoku University has studied in detail, a slow change of microscopic magnetic structures in metallic wires induced by external driving forces, commonly called "creep" motion. This has allowed them to clarify the physics of how the driving forces, magnetic fields or electric currents, act on the magnetic structure.
Previous studies had shown that while the actions of magnetic fields and currents are the same for metallic materials, they are fundamentally different for semiconductor materials.
The present study reveals that in cases where the sample satisfies a certain condition, the current acts on the magnetic structure in a different manner from the magnetic field case, irrespective of the intricacies of the material.
The development of a high-performance magnetic memory device (where the magnetic structure is manipulated by current) has been intensively pursued recently, and the present findings are expected to facilitate the fundamental understanding to achieve the practical application.
The research group fabricated a wire device consisting of a ferromagnetic metal CoFeB, and investigated the universality class of a magnetic domain wall "creep." They evaluated the domain wall velocity for various magnitudes of magnetic field or electric current while keeping the device temperature constant, from which they derived the scaling exponent for the universality class.
The results indicate that the scaling exponent does not depend on factors such as temperature and wire width, for both magnetic field and current cases, confirming the universality of the observed feature. Interestingly, unlike the previous study on metallic systems, they found different universality classes between magnetic field and current-driven domain wall creeps in the present metallic sample.
This means that the actions of a magnetic field and current on the domain wall are fundamentally different from each other. The field-driven "creep" was found to belong to a previously known universality class, whereas the current-driven "creep" was found to belong to a different universality class which cannot be explained by the present theories and the scaling exponent was similar to the one observed previously in the magnetic semiconductor.
From detailed investigations of the behavior of the domain wall under the application of a current, they found that the current gives rise to an adiabatic spin-transfer torque acting on the domain wall which has a different symmetry to the torque induced by a magnetic field. In other words, it was clarified that, for sample in which stack structure is designed so that the adiabatic spin-transfer torque dominantly affects the domain wall, universal creep characteristics appear irrespective of the nature of material, such as metal or semiconductor, the details of microscopic structure.
The obtained findings shed light on a statistical physics of creep motion of elastic interfaces and development of high-performance magnetic memory devices.
'Flipped' classrooms improve physics education: A 5-year study found that Reflective Writing and collaboration changes how well students learn
http://www.sciencedaily.com/releases/201...160633.htm
RELEASE: A feather is dropped on the moon from a height of 1.40 metres. The acceleration of gravity on the moon is 1.67 m/s2. Determine the time for the feather to fall to the surface of the moon.
If this physics problem makes you break out in a cold sweat, you are not alone. And yet thousands of students enrol yearly in university classes to undertake the daunting task of solving questions far more complex than that.
Many of them have difficulty overcoming their physics-induced anxiety.
One Concordia researcher has a solution: flip the traditional classroom on its head.
In a paper recently published in the journal Physical Review, Calvin Kalman, a professor in the Department of Physics, and his research team undertook a five-year study involving close to 1,000 students enrolled in four physics courses at two universities.
Using data gathered during student interviews, writing assessments and a special questionnaire, the researchers found that students can actually improve their thinking and learning by engaging in Reflective Writing and interactive activities.
"It has been shown that in typical physics classes, students' beliefs about their own learning deteriorate or at best stay the same. I want to reverse that result," says Kalman, who is also the principal of Concordia's Science College.
"This study shows that if you combine a meta-cognitive activity with an interactive activity, students can better hone their thinking abilities for that course."
Meta-what?
Simply put, meta-cognition is thinking about your thinking.
"When students engage in Reflective Writing, which is a meta-cognitive activity, they express in their own words what the concepts found in the textbook mean, how they connect to concepts in other chapters and how they connect to personal life experience," Kalman says.
"That's far more involved than a simple cognitive exercise like summary writing, where you just write a précis of the ideas in the textbook, using the same vocabulary,"
The importance of collaboration
Kalman's study shows that students really see rewards when they follow Reflective Writing with a collaborative activity like working with their peers and professors in the lab.
"That combination of activities produces what is referred to as cognitive dissonance -- that feeling of discomfort when the new information you're confronted with conflicts with what you already believe," Kalman says.
When students first grapple with a problem on their own, they may come to the wrong conclusion. Finding out the real solution in a collaborative setting helps improve their understanding, as well as their approach to learning.
Flipping the classroom on its head
"I want instructors to move away from relying solely on the traditional lecture method," says Kalman.
"Instead, I envision what is called a 'flipped' classroom, where students try to understand concepts before coming to class, and then have an opportunity to explore these concepts in the class alongside their peers, and with the guidance of a teacher."
http://www.theguardian.com/science/life-...ette-style
EXCERPT: What is ‘scientific progress’? What does it mean? How is it achieved? Cleary, one avenue is improving our experiments, measuring effects more precisely and developing new experiments which shed light on previously uncharted realms of Nature. But what do we learn from these measurements? Do we verify a scientific theory? Not exactly. The statement “All swans are white.” can not be verified, unless you are certain you have checked every single swan.
Historically, Newtonian mechanics and gravity were the prevailing theory of Nature, supported by all measurements for over 200 years. It was very successful, but not verified. [...] Around 1900, the situation changed dramatically [...] These results falsified Newton’s theory. Black swans had been found! Einstein’s special and general theory of relativity replaced it as a better - but not necessarily true - theory [...]
[...] the Higgs Boson discovered at the LHC in 2012. It was predicted by the Standard Model of elementary particle physics, developed more than 40 years earlier. [...] However, this does not mean that the Standard Model is true? The answer is an emphatic “no”, as we already have a new black swan: dark matter. [...] So why do we still use the Standard Model? Because, annoyingly, it just describe every other measurement so well – and, to be honest, because we haven’t found the new encompassing theory yet. Or have we?
Enter: supersymmetry. [...] if we measure the processes at the LHC precisely enough, we might be able to distinguish supersymmetry from the Standard Model. Alternatively, we could try to falsify supersymmetry, but how? Our proposal is to do it the soft way....
Vacuum Energy
http://physics.about.com/od/physicsutoz/...Energy.htm
EXCERPT: Vacuum energy is the energy created by empty space by the constant creation and destruction of particles by the quantum fields that fill the universe....
Physics for the mechanism of slow change in microscopic magnetic structures revealed
http://www.sciencedaily.com/releases/201...105305.htm
The research group of Professor Hideo Ohno and Associate Professor Shunsuke Fukami of Tohoku University has studied in detail, a slow change of microscopic magnetic structures in metallic wires induced by external driving forces, commonly called "creep" motion. This has allowed them to clarify the physics of how the driving forces, magnetic fields or electric currents, act on the magnetic structure.
Previous studies had shown that while the actions of magnetic fields and currents are the same for metallic materials, they are fundamentally different for semiconductor materials.
The present study reveals that in cases where the sample satisfies a certain condition, the current acts on the magnetic structure in a different manner from the magnetic field case, irrespective of the intricacies of the material.
The development of a high-performance magnetic memory device (where the magnetic structure is manipulated by current) has been intensively pursued recently, and the present findings are expected to facilitate the fundamental understanding to achieve the practical application.
The research group fabricated a wire device consisting of a ferromagnetic metal CoFeB, and investigated the universality class of a magnetic domain wall "creep." They evaluated the domain wall velocity for various magnitudes of magnetic field or electric current while keeping the device temperature constant, from which they derived the scaling exponent for the universality class.
The results indicate that the scaling exponent does not depend on factors such as temperature and wire width, for both magnetic field and current cases, confirming the universality of the observed feature. Interestingly, unlike the previous study on metallic systems, they found different universality classes between magnetic field and current-driven domain wall creeps in the present metallic sample.
This means that the actions of a magnetic field and current on the domain wall are fundamentally different from each other. The field-driven "creep" was found to belong to a previously known universality class, whereas the current-driven "creep" was found to belong to a different universality class which cannot be explained by the present theories and the scaling exponent was similar to the one observed previously in the magnetic semiconductor.
From detailed investigations of the behavior of the domain wall under the application of a current, they found that the current gives rise to an adiabatic spin-transfer torque acting on the domain wall which has a different symmetry to the torque induced by a magnetic field. In other words, it was clarified that, for sample in which stack structure is designed so that the adiabatic spin-transfer torque dominantly affects the domain wall, universal creep characteristics appear irrespective of the nature of material, such as metal or semiconductor, the details of microscopic structure.
The obtained findings shed light on a statistical physics of creep motion of elastic interfaces and development of high-performance magnetic memory devices.
'Flipped' classrooms improve physics education: A 5-year study found that Reflective Writing and collaboration changes how well students learn
http://www.sciencedaily.com/releases/201...160633.htm
RELEASE: A feather is dropped on the moon from a height of 1.40 metres. The acceleration of gravity on the moon is 1.67 m/s2. Determine the time for the feather to fall to the surface of the moon.
If this physics problem makes you break out in a cold sweat, you are not alone. And yet thousands of students enrol yearly in university classes to undertake the daunting task of solving questions far more complex than that.
Many of them have difficulty overcoming their physics-induced anxiety.
One Concordia researcher has a solution: flip the traditional classroom on its head.
In a paper recently published in the journal Physical Review, Calvin Kalman, a professor in the Department of Physics, and his research team undertook a five-year study involving close to 1,000 students enrolled in four physics courses at two universities.
Using data gathered during student interviews, writing assessments and a special questionnaire, the researchers found that students can actually improve their thinking and learning by engaging in Reflective Writing and interactive activities.
"It has been shown that in typical physics classes, students' beliefs about their own learning deteriorate or at best stay the same. I want to reverse that result," says Kalman, who is also the principal of Concordia's Science College.
"This study shows that if you combine a meta-cognitive activity with an interactive activity, students can better hone their thinking abilities for that course."
Meta-what?
Simply put, meta-cognition is thinking about your thinking.
"When students engage in Reflective Writing, which is a meta-cognitive activity, they express in their own words what the concepts found in the textbook mean, how they connect to concepts in other chapters and how they connect to personal life experience," Kalman says.
"That's far more involved than a simple cognitive exercise like summary writing, where you just write a précis of the ideas in the textbook, using the same vocabulary,"
The importance of collaboration
Kalman's study shows that students really see rewards when they follow Reflective Writing with a collaborative activity like working with their peers and professors in the lab.
"That combination of activities produces what is referred to as cognitive dissonance -- that feeling of discomfort when the new information you're confronted with conflicts with what you already believe," Kalman says.
When students first grapple with a problem on their own, they may come to the wrong conclusion. Finding out the real solution in a collaborative setting helps improve their understanding, as well as their approach to learning.
Flipping the classroom on its head
"I want instructors to move away from relying solely on the traditional lecture method," says Kalman.
"Instead, I envision what is called a 'flipped' classroom, where students try to understand concepts before coming to class, and then have an opportunity to explore these concepts in the class alongside their peers, and with the guidance of a teacher."