Wednesday, May 31, 2006

Community of minds

A school that works well needs faculty that are in synchrony. After that the students feel the good vibes and they themselves flourish. It is not so easy to be a gardener of minds. 

The way of the mind

Today I was talking to two of the best students in the high school. They were somehow constrained by the faculty, it seemed that they had overstepped some boundaries of decorum. For my taste it was a bit risquè but acceptable. Nevertheless I feel that my limits of acceptable behavior do not always coincide with the rest of the faculty. I bring this about because of another more academic matter that intrigues me right now.

This has happened to me; I have an idea in the middle of a presentation, and I plunge in trying to prove it. Sometimes I catch myself in dangerous territory and back up. Going back to the regular line of argumentation. If I am training mathematicians or scientists this is healthy, if I am training high school students this can be disconcerting.

There are some high school students more than ready to be trained this way. One needs intellectual partners to go the way of the mind. I worry about gifted students with square caregivers, but that is life.

I am glad I met some very bright students this year.


I just read this book by Charles Mann.

To my mind it tells us that we have to go back and take back the land, just like our indian elders were doing it (yes, I am part Mayan).

Interesting concepts, maybe they are true.

A new physics course?

Physics is a hard science. The current core starts with Newton's Principia from 1687; then we end with quantum and relativistic physics, that is basically 1915. Does this need to change?

Maybe more chaos theory, and complex phenomena, together with nanotechnology, among other topics. Unfortunately the core has not changed. There is no Theory of Everything, not even a Quantum Theory of Gravity. Fundamental physics got stuck in 1915.

Brown girl

The stuff we learned was interesting but it was hard to learn at first. After I got used to the teaching style and began doing individual stuff, it was actually fun.

This is an anonymous post by a student on my WebPage:

This is my response:
I like that. It was fun.

Next time around though. I plan to work more directly with students. Some ideas.

The first day of classes, give a pretest like this year; but unlike this year, I won't let the students off-the-hook, until they know all the concepts in the pretest. This year I gave the pretest again at the end of the year, and I did not see much improvement. A week for this seems reasonable, all the class and I, talking about what physics is all about.

The second week give a math pretest. This I expect will take more than one week. We need, arithmetic, algebra, geometry, and vector algebra. The last topic will just be introduced, we will work all year on this mathematics topic together with trigonometry.

Now we are ready to start. I do not plan to cover a book almost cover to cover as I did this year. A more qualitative approach seems to work at the high school level; definitely more emphasis on experiments and demonstrations is better than the more abstract approach I took.

All of you did almost everything I asked from you, for that I thank you. I was expecting you to do more than I asked; some of you did, I am very impressed with you and I think you will do well in academic and practical work.

Finally next time around, I will put my students in a little more stress, as long as nobody gets hurt; I think it is actually good for students to work harder and direct them away from a lot of entertainment that is not productive.

Tuesday, May 30, 2006


My rank is very low:

Rank: 1,205,569 (0 links from 0 sites)

I am a novice on the blogosphere. I do not exist. 0 links from 0 sites. One million and two hundred and five five hundred and sixty ninth place, at the bottom of the heap, today May 30, 2006.

How do I know that you know?

I know that you know physics when I see you solving physics problems, and when I see you setting up an experiment to prove a principle or any regularity observed in physics.

For the basic conceptual core of physics, I do not have to warn you, I just ask and you respond. This is not different than knowing spanish. I start talking and you respond, you do not need your book.

I hope my students in the future can talk physics when the course is over. I am not there yet.

College without high school diploma?

You can check in today's New York Times (NYT) the following:

I gave high school students a conceptual physics test today. I did not ask them to study for it, I just asked them the same questions I asked them at the beginning of the year.

Then I read the above article informing us that some colleges take students without General Education Development (GED) diploma, nor high school diploma.

My opinon is that everybody deserves a place in college, but they have to demonstrate high school equivalency.

As far as my students are concerned, I believe they will do well in college, but they definitely need to know more physics.

Sunday, May 28, 2006

Milgram's Experiment

This is an old experiment which will help us remind that technology shouldn't be dictated by corporate freaks.
We all know already what GOOGLE did in CHINA.
GOOGLE please stick to your motto 'Don't be evil!!!'

This is a classic scientific experiment. We should not forget.

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Random thoughts

This note may help me to collect my thoughts. Recently I have been thinking about my life contribution before I die. One of my deep interests has been the nature of entropy. I do not give references here, but I have read the work of some thinkers, some very successful, and some not so much.

I see two intimately related aspects of the concept of entropy, one is the entropy of the system, the other is my perception of that entropy. Objects are mental constructs, we choose where something begins and where something ends. When we count the number of objects we are using a filter. The filter is not part of what is outside. Our filter introduces randomness, and therefore increases the entropy, as another observer looking at us trying to count the objects may himself perceive. Among human beings we use the peer review method to agree on how many objects we all count. But I feel that either another type of intelligence, or maybe the thing itself, whatever that means, gives a similar number of parts.

Shannon defined information taking both aspects into consideration, a message is not something in itslef, it depends on who gets the message. The recipient of information has expectations, Shannon's information incoprporates in an intrinsic way those expectations.

Now Quantum Information. The wave function of the Universe counts all the ways the Universe could have been when we ask a question. Both the question and the Universe define the probablilities we give for the Inflationary Universe say, according to Hawking they are much bigger than zero. If I understand  correctly what Hawking is saying, Alan Guth has to be given a Nobel Prize.

Science in the US

American students are not as much into science as I want them to be. I think future citizens of the world  have to be rational and passionate about understanding our Universe and our place in it.

An almost religious attitude about the role we play in the Universe is a must, in my mind, if we are going to survive.

On the other hand the understanding of the Universe gives us pleasure and helps us find meaning in life. 

Why American College Students Hate Science

Science education faces two serious problems. The first is that too few Americans perform at the highest level in science, compared with our competitors abroad. The second problem is that large numbers of aspiring science majors are turned off by unimaginative teaching and migrate to other disciplines before graduating.

The article ends with:

"The university community needs to absorb these lessons quickly, so the country can begin to train scientists in the numbers that it clearly needs. Without them, America is unlikely to preserve its privileged position in an increasingly competitive and science-based global economy."

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Friday, May 26, 2006

End of the school year

Before I write my reflections on this year's experience as a high school teacher, I write one comment on Internet dialogue. Recently I checked two posts one on nuclear fusion energy research and another on global warming. The first comments on were civil and I felt like adding my 5 cents. The comments for the second post were virulent, I did not write any comment. I see the difference this way, the first one is not controversial because the fusion nuclear plants are not ready, maybe a few negative comments on the billions of dollars already spent. The second set though, is different. Vice President Al Gore is asking all of us to do something. There are worrisome signals we can choose to look into or just ignore. I assume the negative and emotional comments against Mr. Gore are a good thing, whoever is writing with so much passion must feel something, maybe when the time comes she or he will do what is necessary.

There are strong opinions on high school science education also. I just read in the New York Times, that the twelfth grade science students performed worse this year than a few years back. I teach eleventh and twelfth grade physics students. These are my opinions and reflections on my year's work.

I was surprised the first day of classes, I gave them a pretest on physics concepts. I did not find a good grasp of physics concepts. Today was my last day before finals next week. I am not very happy.

There is a part that is my fault, and another one that I believe is the fault of the students. I only talk bad about me. This is what I did wrong; at the end I write what the students did well. By the way my son is in middle school and I am not happy about that either.

After the physics concepts pretest I should have had one on mathematics skills. After the results I should have spend two or three weeks on stating and practicing the mathematics that we need for a high school physics class. That would have set the tone, we have to get this right guys, so we can move on. I treated the high school students as if they were in college and self regulated besides. This method only worked half way, I explain at the end.

Since I myself did not spend time doing many problems, the students did not do many problems either, only the problems assigned. I did not do many lab sessions, so the class was abstract, and I believe outside the radar screen of some students, the ones that did not do the problems in tests well. You see, I know how to do the problems, so I did not notice that the students could benefit a lot from seeing somebody doing the problems. I emphasized the ideas behind the course, the important ideas of physics, and did not spend enough time with the nitty gritty, which is the bread and butter of novices.

The worst aspect of my teaching practice was the follow up and students wrong work. Next time around most of my time will be spent on working with students work. Good work and bad work. Now I finish this post with a positive note.

I was flabbergasted by the quality and originality of the final presentations.

Once I saw that I was doing all the talking and many students had lost interest, I decided to change course. Let them do the talking. I gave a list of special topics in physics and the students chose from it, or requested to speak about other topics. After considering whether or not we were going to learn some physics I let the students go ahead with their presentations.

We had a flash animation on the laws of motion. When my daughter was in high school, she made a movie every year, this presentation reminded me of her. She would take her camera and shoot very interesting stuff around town or at school. There were good power point presentations by the students from roller coasters to nuclear reactors, passing through elementary particle theory. There were two poster presentations on the Big Bang Cosmology of Lemaitre-Friedmann-Robertson-Walker-Hubble-Gamow-Guth; one on the Illinois State Energy Program, and one on Einstein's 1905 Annus Mirabilis. I felt like crying; it felt so good to see all the extra work the students put on expressing themselves; they talked about thermodynamics, astrophysics, quantum mechanics, and special reltivity. It was exciting.

I asked around after the presentations, talking to students one on one, to find out how much physics they know. I finish this note with a bitter sweet comment.

I am afraid that not all the students would do well in a regular standarized physics test. Some are brilliant and will do well in almost any test that may come their way. I know they want to learn physics, I just hope that I started enough curiosity for some of them to look deeper into physics in particular, and science in general. I hope they find relevant science.

Thursday, May 25, 2006

Comprehensive List of Mathematical Formulae and Concepts

This is a 66 page LaTeX/PDF document of just about every mathematical concept out there. It is written at an advanced undergrad/graduate level, and is a great reference for any mathematics student or engineer.

Saves a lot of time if you need to type these formulas in your work.

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You can find this author's LaTeX file for physics here.

Physics Formulae

Fusion reactor work gets go-ahead

Seven international parties involved in an experimental nuclear fusion reactor project have initialled a 10bn-euro (£6.8bn) agreement on the plan.
The International Thermonuclear Experimental Reactor (Iter) will be the most expensive joint scientific project after the International Space Station.

Fusion reactions power the Sun, and before the century is over, could be heating our living rooms.

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Student Presentations

The school year is coming to an end at the high school. This week we had a series of over twelve presentaions. The topics were varied, from classical mechanics to modern physics. Some of an applied nature, and some knowledge for knowledge's sake. Some of the later are: Was there a beginning of time? If there was one; would we know more of what happened near this beginning of time? Some of the former are, How does a nuclear reactor work? What is the Illinois State Energy Program?

A constant element I want to report here in this forum of relevant science, is the student enthusiasm I observed. To tell you the truth, I was a little bit surprised. I did not see the same level of participation, most of the year. Only when I let the students free to create their own expressions, did I see this response. Next year I will do more of this. Of course it helps that grades are given, and students want to do well on the final. The currency at school is the grade. I expect good grades in general. As a teacher I feel that students should enjoy their work, but also this work has to be of the highest quality the students can do.

To conclude; at the end of the day, their knowledge of physics will be evaluated by people different than I. I hope enough enthusiasm was created , for them to keep learning physics. This ride does not end.

Saturday, May 20, 2006

Centrifugal Forces

"Maliki, a tough-talking defender of Shi'ite interests since his return from exile in 2003, has won praise from Sunnis for his willingness to seek consensus. But many question whether a government cobbled together according to religious and ethnic labeling can overcome centrifugal forces tearing Iraq apart."

This quote is from today's New York Times.

Centrifugal forces are fictitious. How could fictitious forces torn a country apart?

Friday, May 19, 2006

Energy Use

One of the Special Topics the students are preparing for next week is about energy use. We talked about Newton's Law, F=ma, and how one can change that way of describing motion to, mv^2/2 + mgh = constant, then and there energy appeared in the high school classroom. Somehow though, I felt I was not getting across. Do the students know that when they go to the gas station, they are paying for energy?

After several days we went in a field trip to Six Flags, Great America, on Physics Days. Again; what is kinetic energy, and potential, and mechanical energy? Do they relate that to the price of gasoline?

I do not feel that most of us internalize what we learn at school and real life.

Some tips to understand, why gasoline is over three dollars a gallon?

"PROVIDENCE, R.I. (AP) -- If you've stopped to fill up your tank recently you've seen it: Gas prices have surpassed the three-dollar mark.

The state Energy Office says its latest survey found gas averaging three dollars and one cent a gallon. That's seven cents more than last week. It's also an increase of 82 cents, or 37 percent over this time last year.

A survey by Triple-A of Southern New England finds gas prices averaging three dollars a gallon."

Let me start with F=ma. I know my students ask me not to derive equations, just tell us what the equations are, and how to use them.

I feel that if I use words and no equations, I am allowed to "derive" results.

Newton wrote over three hundred years ago that inertia requires an external agent to change velocity. Let's see; car is at rest in the garage, or wherever you parked it. Inertia being what it is, it won't budge. It weighs over a few thousand pounds. We have two options, we may pull it with a rope, there is the F of old Isaac, or just turn on the motor. Little electric spark, and the fire inside starts. Somehow we don't see the force now, but the internal combustion engine is on fire, and it moves the wheels.

Where did that fire inside the gasoline come from?

To the best of my knowledge, there were dinosaurs happily munching food sixty five million years ago in the Yucatan peninsula; a big rock hit the Earth, and they passed away. After many years they became oil, and then gasoline.

First tip.

Rocks like that, do not come often; that is our good luck. Many of them and we will go the way of the dinosaurs.

Scarcity means high prices. That is the first tip to explain three dollars a gallon.

Second tip.

The Yucatan dinosaurs are being sold now by Mexicans and Americans, there are Arabs selling theirs also. Dead dinosaurs are a non-renewable resources.

Third tip.

We should be getting the energy from where the dinosaurs got it. Frist from plants, and then from the Sun directly.

How does F relate to energy?

That is called the work-energy theorem, that will be a different post on this site.

Disordered locality

Smolin reports in his review on quantum theories of gravity, that when one considers discrete ways to connect points through edges; a smooth spacetime emerges. Nevertheless there is redundancy. More than one object corresponds to a given volume say. This can be described as "disordered locality".

Locally there may be room for creation, but globally the object seems fixed. Neat idea. Maybe this is the origin of Quantum Mechanics.

From Research to High School

I worked for eighteen years as a physics professor at the Benemerita Universidad Autonoma de Puebla in Mexico. I had a few stints as a software engineer and part time college instructor in Illinois. Now I am teaching physics in high school, also in Illinois.

I did not publish enough to work in research. To this day I spend time following research work in physics. The work as a teacher requires effort, and I have to find a happy medium, I am afraid that sometimes I do not achieve that happy medium. It is good that I follow current research so I can interest my students to consider a scientific career; sometimes though I feel I could do more to help the students that are struggling with their physics work.

Maybe I should strive to be a human being, not a researcher, or a college professor, or a high school science teacher. From certain distance my predicament seems amusing.

Just give us the equations.

I finished my student teaching practice at Glenbard East High School in Lombard. In my physics web page you can read the comments by my students after a whole year of study. A recurrent complain I had during the year, that shows up again in the WebPage, is the difficulty in deriving physics formulas. Students prefer to be given a list of formulas with indications as to when to use them, instead of deriving them in class.

This was an error in my lessons. I forgot how was it when I was the age of the students. In the beginning one does not see the point in coming from first principles and deriving general results. Tasks have to be specific. It is only after months of familiarity with the subject matter that patterns appear in our mind. They are right and I am wrong. Next time around I will be more concrete, more demonstrations and experiments, and as the course develops then it will get more abstract. I myself do not have a very abstract mind, the previous note on Plebanski's action is an introduction to a subject that requires more mathematical knowledge than what I have right now. We are all in this continuum of understanding, some of us are more concrete than others, but all of us should move up in the "abstraction ladder"

The Plebanski action

Jerzy Plebanski was a great man. He was born in Poland and died in Mexico City. Unfortunately we did not interact as much as I would have liked. He was the first director of the Physics Department where I got my Master's Degree at Centro de Investigacion y Estudios Avanzados (CINVESTAV), Instituto Politecnico Nacional (IPN), in Mexico City. By the time I got to CINVESTAV he was back in Poland, then I went to California, and he came to stay in Mexico.

Prof. Plebanski worked with Leopold Infeld, another great Polish physicist that wrote the "Evolution of Physics" with Albert Einstein, a classic science popularization book. Here I want to pay tribute to this great physicist. He discovered how to separate einsteinean substructures in General Relativity in 1976. This was unknowingly used by Ashtekar to prove that General Relatvity (GR) is a Gauge Theory.

"All known classical gravity theories such as GR and supergravity in any dimension are diffeomorphism invariant gauge theories. Hence they all provides examples of causal spin network theories. But it's even better than this, because the dynamics turns out to act simply on the spin network states, through local moves of the kind described above. This is a consequence of the second principle, which is that the dynamics of all known classical relativistic gravitational theories are arrived by perturbing around[14] or constraining topological field theories[15]. In 4 dimensions one route to this is through the Plebanski action[16]."

This quote is from a recent review by Lee Smolin of Quantum Gravity theories.

This is relevant science because my generation of physicists is trying to construct a Quantum Theory of Gravity, and Plebanski's decomposition of Einstein's Theory is considered an important step in unifying the mathematical structures of quantum theory and classical Differential Geometry, which is the foundation of General Relativity.

The Plebanski action is a simple code to express the dynamics of space time.

Tuesday, May 16, 2006

How to Teach Modern Physics

I am teaching high school physics. This month we have been studying Modern Physics. I use a college level textbook because these are classes for gifted students; nevertheless I feel that the subtleties of Modern Physics were not understood.

These are some thoughts on how to do this better.

It is crucial to have interested students, these subjects require thinking, by their nature they are abstract. We do not move at the speed of light nor see quantum objects every day. These subjects are mathematical in nature, and some times even gifted students do not know enough mathematics. My emphasis was conceptual, I had to make analogies to water waves and classical physics concepts, but I felt that the unique character of relativistic quantum objects was not grasped by some students.

All in all I prefer a course in which these notions are presented than one in which they are not. After all we do live in a quantum relativistic universe and we should make an effort to understand it.

Next time around though, I will require more effort on the part of the students to grasp these concepts. I can help, but in the end there is no substitute for good all hard work.

Wednesday, May 10, 2006


I read comments on Hawking-Hertog; these gentlemen use Hartle-Hawking.

I read Hawking-Hertog a few days ago. My conclusion is that it is an accomplishment to derive Inflation. Now we should just wait for the other predictions to be vindicated, and we will have one of the first Quantum Gravity theories.

Not just our minds, also experiments are essential to know the truth.

Stephen Hawking says, right now you're actually creating your Past!

Hawking and Hartle's original work on the quantum properties of the cosmos suggested that imaginary time, which seemed like a mathematical curiosity in the sum-over-histories approach, held the answer to understanding the origin of the universe


Good things coming from them.

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Tuesday, May 09, 2006

Design or Accident?

Prof. Frank Wilczek from MIT writes in the May issue of Physics Today about fundamental constants. Max Planck on discovering the constant that bears his name organized several fundamental constants to calculate what we now know as Planck's length, time, and energy.

As you may remember from school physics, all physical quantities can be expressed in units of length, time, and mass. One could say, that every ponderable object of our physical Universe, at some level is related to deep fundamental notions of space-time-matter.

The question is, are the values of these fundamental constants an accident, or were they "fixed" by some higher being?

There are books written about this question with different answers, here I just add my answer.

This is a meme. I am not going to be completely original. This is just my current version of the answer. By writing it here it becomes part of the noosphere, or blogsphere, or memespace, or memeland.

If you think of Design as the left, and Accident as the right side of the spectrum of answers, mine is veering towards the right. I definitely believe in some design, but it is design by the Universe itself. I do not believe that there was a previous Universe to this one that had a plan for us. I prefer a self contained answer, all in this Universe.

In the beginning the Universe was so simple that it did not have any plans, for itself or for us."US" means sentient living organisms.

I believe in Emergence, from a simple Universe, a more interesting and complex one is constructing itself. The answer is then:

In the beginning there was no plan, all fundamental constants were equally likely, as time passes, and good things are found, they are kept. Good is what remains.

Nowadays all constants have just the right values to keep good things going. I believe in a self-regulated Universe. Constantly tweeking the knobs, until all conditions are right. If we are good, we will be invited to play with the knobs.

We have not been very good. We are taking our house to the brink of destruction. Global Warming is already the result of our careless management of the house we were given. We better believe it, there is no plan for us to stay here, if we don't help it happen, we won't be around to the end of our Solar System.

Monday, May 08, 2006

Moon Representation in Mexico

Old Moon monolith announced yesterday in San Luis Potosi Mexico.

This huge monolith could be 2800 years old.

Cosmology and Elementary Particles

I started my studies on Theoretical Physics with Quantum Electrodynamics. I believed that experiments are the best guide for theoretical speculations. I am surprised though, by the pace of advances in Cosmology in the last thirty years. The Hubble space telescope and other satellite based instruments have increased our knowledge of the Universe tremendoulsy. Now we know that the electron and the photon of my initial studies comprise less than one percent of all the stuff that fills our Universe.

Presently I am reading "The View from the Center of the Universe" by Joel Primack and Nancy Abrams

I have changed my mind, there is much to learn, without using only Earth bound accelerators.

Saturday, May 06, 2006

Wednesday, May 03, 2006

Nuclear Physics

A proton and a neutron form a stable nucleus called deuterium. A free neutron decays in 15 minutes. I wonder if americans and mexicans have a similar relation. Who is the proton and who is the neutron?

NYT on Immigrants


Tuesday, May 02, 2006

A Day Without an Immigrant

What does it mean? How could millions of people that officially are not here, stop economic activites for one day?

digg RSS Widget for Dashboard -- Version 3.0

The widget just got some major updates, including being able to choose which feed to view, if you want to digg for stories, and the ability to see stories which have been dugg, submitted, on the front page, or commented on by a specific user. The widget also has an optional extended view which lets you view stories' descriptions.

Check it out.

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