Here it is:

Download Worksheet

Download Answers

Subscribe on the right hand side by simply entering your e-mail address (nothing more required).

You will then receive a newsletter on all of our new posts ! Don’t miss out !

Students who are U.S. citizens or permanent residents majoring in science, mathematics and engineering may apply to participate in a variety of research programs with the National Institute of Standards and Technology’s Gaithersburg, MD Summer Undergraduate Research Fellowship (SURF) program for students.  NIST will provide a $4,500 stipend as well as housing to students who participate for the full 11 week program.

4 phy – Here are some links, which you might find useful when researching NEOs today: NASA, wikipedia, UK National Space Centre, NEO tracking and the asteroid that killed the dinosaurs. Good luck!

Elastic Water could eventually replace plastic, or be used in an environmentally-safe plastic.

Bernama, a part of the Malaysian National News Agency, reports that Japanese scientists have created “elastic water.” Developed at the Tokyo University, the new material consists mostly of water–95-percent–with an added two grams of clay and organic material. The resulting substance resembles jelly, but is extremely elastic and transparent.

The invention was originally revealed last week in the latest issue of the Nature scientific magazine. According to the article, the new material is quite safe for the environment and humans, and may be a “long-term” tool in medical technology, possibly to help wounded or surgically cut tissue to remain closed.

Bernama also reports that–by increasing its density–the new material could be used to produce “ecologically plastic materials,” or could replace plastic altogether. This aspect is still under investigation until September 2010. However, if successful, the scientists may have found a way to make the world a little greener.

via Japanese Scientists Create Elastic Water – Tom’s Guide.

See the “High-water-content mouldable hydrogels by mixing clay and a dendritic molecular binder” article in nature.

I’m taking a graduate statistical mechanics course this semester. My first physics theory course in more than two years, and my first graduate physics theory course.

One reason I started disliking physics theory courses when I was an undergraduate was that class time was spent almost entirely on going through the details of the derivations in the textbook. If there’s anything guaranteed to send me to sleep, especially if it’s a 9.30am class, it’s someone at the board moving symbols here and there and reciting the arithmetical rules he’s using to move those symbols. Furthermore, the vast majority of derivations are mathematically straightforward and can be understood from a close reading of the textbook. I don’t need someone to go through what I can glean from reading the textbook on my own.

For whatever reason, I thought that graduate classes in physics theory would be better. Well, this one isn’t. The professor is going through nearly every single line in Pathria’s text. What’s more, he actually tells us to read the textbook beforehand because he doesn’t want us to be looking at the textbook figuring out the math while he’s “teaching”. But if I read the textbook beforehand (which I do), I understand the derivation, so I get bored when he comes to class and goes through the exact same derivation, except more slowly and in more painful detail. So far I’ve always ended up working on my problem sets during class instead, which I find a much more productive use of my time.

One point that Eriz Mazur makes in this excellent talk on science education is that in a humanities class, it’s standard to expect students to do the assigned reading. The class then proceeds with the assumption that students have done the reading. The instructor does not hold your hand and lead you through every line of the reading. It is also understood that if you don’t do the readings, it pointless to go to class because the class is going to assume you’ve at least grappled with them, and start off on that higher level.

The opposite happens in science classes. In the vast majority of physics theory classes I had, even if the professor recommends that you read certain parts of the textbook or lecture notes, s/he still leads you by the hand through the very material that you’ve just read. You could not read any of it and still get the contents of what you were supposed to have read through the lecture alone. (The one class I had that did not follow this mould, which was also my favourite class in any subject ever, was taught by someone who would receive negative feedback from most students about his more Socratic teaching style. People complained that he did not follow a textbook, but for me, it is exactly when someone follows a textbook that his lectures fail to add value.) The learning style encouraged by such teaching seems to be passive rather than active, compared to humanities classes.

All this may be excusable as a sop to undergraduates who are either too stupid or lazy to read textbooks on their own, but firstly, the same undergraduates are not treated as such by their humanities instructors, and secondly, why is this still going on in graduate classes? Why do graduate students have to be hand-held through a textbook? If you can’t read a textbook like Pathria on your own, should you even be in a physics theory PhD programme?

A useful contrast is with my philosophy graduate seminars. There, as with undergraduate humanities classes, you’re expected to do the readings before class. Discussions in class proceed on the assumption that you have done your readings. Students are typically asked to present some of the readings, and the presentations will have some sort of summary of the contents of the readings, but it’s nothing to the extent of the presenter going through step by step of the arguments in the readings, the way physics theory teachers go through the textbook derivations step by step. And of course, there is much discussion of the readings.

I discussed this with someone before, and the response was that in science, there is typically a definite “right answer” to questions, whereas in the humanities, most of the important answers are still unknown. The implication is that if there is a “right answer”, then this should be told to the students. In contrast, if the right answer is not known, then discussion might somehow bring one closer to it.

I suspect many people think of science education this way, and I think they’re deeply mistaken. The objective of science education as I see it is not to tell people the right answers. The objective is understanding. People may know the right answers without understanding why they are right. In physics theory, the analogue would be if a student could do all the problems set by her instructor by the simple expedient of applying certain formulaic rules, but does not understand why those rules hold. This was my situation for most of my physics theory classes, and was a huge contributor to why I became frustrated with physics theory. Of course, I did go to my professors outside of class to try to get a deeper understanding, but most of the time they could not answer my “conceptual” questions. They seemed to be prepared only to tell students how to apply certain rules, without being able to justify those rules themselves.

The peer discussions that Mazur and an increasing number of people who study science education are advocating go some way to helping students get to the answer on their own and, on the way, gaining a deeper understanding of why the answer is what it is. It makes science education more like humanities education.

Pushing the idea further, I see no reason why a graduate class in physics theory cannot be run like a graduate class in philosophy. Have the students read the relevant section of the textbook beforehand. This should be just as obligatory as doing the readings for humanities classes is. In class, ask if anyone has had any problems understanding the assigned readings. If someone has, try to straighten her out. Do not go through every step of the proofs in class, since it could (and should) well be the case that most students understand the proofs already. Class time should be used instead to discuss interesting implications of the proofs, setting the context for them, considering the assumptions they use and what implications those assumptions have, and so on. In fact, I also see no reason why the model of having students present on the assigned readings cannot be applied. Do physics theory professors have such low expectations of their students that they think they cannot learn on their own and have to be spoonfed just like undergraduates? Or is it I who has overly high expectations of physics theory graduate students?

If you ask a physicist what a “force” is, he or she is likely to answer with a formula for measuring the effect of a force, like F=MA (Force = Mass X Acceleration or “W=FD” (Work = Force X Distance, which translates to Force equals Work divided by Distance F=W/D).  However, the physicist has not told us what a “force” is, only how to measure it in terms of other variables, like “mass” and its “acceleration.” A force may equal mass times acceleration, but is a “Force” in its essence, a “mass” times its “Acceleration”?  A “Newton”, named after Isaac Newton, is the classic unit of measurement of force. In the F=MA formula, force of one Newton will be the product of a mass of one kilogram multiplied by an acceleration or increase in velocity in the amount of one meter per one second, N=KgM/S, but this is only a quantity stated in kilogram-meters per second. That does not tell us what a force is, only how big or small it is, relative to another quantity of force.

The dictionary definition of “force” is typically something as simple as “a pushing or a pulling” or as ambiguous as “a power to influence, to cause. . .”  A “power” is a “capacity” or “ability” or “capability” which is only a word substituting for the description of the quality of an object or thing that can cause an event. Thus, “Force” is a concept used in place of whatever it is that effectively causes a push or a pull, and may be called a “power,” if it inheres in a thing.  Gravity is a force because it is an attraction between things with mass, sometimes referred to by physicist as a “body.”  If you think about it, you can see that no one really knows what a “force” is, what its essence is.

The great polymath genius, Gottfried Leibniz , who contemporaneously with Isaac Newton invented the calculus, stated:

If God would cause a body to move free in the aether round about a certain fixed centre, without any other creature acting upon it:  I say, it could not be done without a miracle;  since it cannot be explained by the nature of bodies.  For, a free body does naturally recede from a curve in the tangent.  And therefore I maintain, that the attraction of bodies, properly so called, is a miraculous thing, since it cannot be explained by the nature of bodies.

Isaac Newton did not know what gravity was, but he was adamant that it was not inherent in matter. He wrote:

It is inconceivable that inanimate brute matter should, without the mediation of something else which is not material, operate upon and affect other matter without mutual contact…That gravity should be innate, inherent, and essential to matter, so that one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it.

Janiak, A. (ed.), 2004, Newton: Philosophical Writings, Cambridge: Cambridge University Press, p. 104, cited in the Stanford Encyclopedia of Philosophy.

Force may be mechanical, when one billiard ball strikes another, or it may be a field, as in the case of gravity or electro-magnetism, but its essence remains undefinable. Physicist today are even using a gravity particle in models, the graviton, to stand in the place of the force of attraction between bodies, as if bodies send invisible massless particles to cling to another body within a certain range and then the respective clouds of gravitons simultaneously push or pull the body towards their respective home bodies, with a strength proportional to the mass of the graviton’s home body, and the stronger cloud of gravitons prevails.

Do we need to know what a force is? If we do not know what it is, where it comes from, why it is here, then we do not know the ultimate source of what there is and what makes it change. We can ignore the essence of the forces in creation, respect it, fear it, or worship it.

The worlds of the Starwars films were managed by “The Force,” an impersonal mystical governing force, which was a conceptual substitute for the personal God who has filled the same role in the Judeo-Christian tradition, only with the historically revealed purposes of a conscious intelligent person.

For the Christian, Jesus Christ, the Word of God, and the person of the triune God by whom creation is carried out to completion, that divine person and spirit is the force that holds the quarks in place and manifests further as the power that is harnessed within the nucleus of the atom, holding its parts together with the strong and weak nuclear forces, until released by massive man-made fission or fusion reactions; is the force referred to as gravity that holds a star together, while though natural fusion within the star, the energy of the forces holding the atoms together is released by means of natural fusion, and is the power that attracts dark matter towards the center of mass of a passing galaxy, and is the force that sends an apple to the earth:

He is before all things, and in him all things hold together.

Collosians 1:17 (NIV)

Dear physics theory,

I never thought I’d say this, but, well, here goes: I miss you. Chemistry is just so messy. And not in the crazy-good sort of way. In the  unit conversion, stoichiometric, beräknade sort of way.  I mean, Chem will be good for me, something different for a little while. But just promise you’ll take me back next term, okej? I promise I’ll try harder too.

From Sweden with Love,

Arielle

Readers of this extreme science blog might want to stop by my Berkeley, Naturally! site and take a look at my latest post:

Berkeley Hills Landslide

We had a series of very powerful El Niño-related storms last week in California, and I wrote about the effects here in the Berkeley Hills and San Francisco Bay Area. (see Berkeley Hills-El Niño Storms Hit Hard)

In the Berkeley Hills Landslide post, I share some pictures I took of a small landslide in the Berkeley Hills. I then go on to discuss some of the science of landslides. Along with my own photos, you’ll find some incredible images of some really big landslides, as well as some links to a couple of amazing landslide videos.

Holbeck Hall Landslide - England 1993 - British Geological Survey

Stop by and have a look! I think you’ll find it interesting and informative.