The Pendulum and SHM

Today, after reaching consensus on the homework problems for SHM, watch and take notes on the pendulum...it is very close to SHM, with one small exception.  There will be something called the small angle approximation you will need to use to get it looking like SHM.

Check out the video here.

TED Talk: Why Do We Sleep????

We all need it, but WHY?  Why do humans spend, on average, one-third of our lives sleeping??? Russell Foster's TED talk begins to address what we know (and don't know, which is a lot) about this question.

A Brief Overview of the Standard Model

This is a nice, brief (~5 minute) overview of the Standard Model of particle physics.  The SM is the current theory of matter and forces, with the one exception of gravity.  This was also made just before the discovery of the Higgs boson, but it mentions where the Higgs fits in.  If you are interested in more details, see Doc V!  Keep in mind that in the particle physicist's mind, we are not made from electrons, protons and neutrons - we are made from electrons, up quarks and down quarks! Check it out for a primer.

For Periods 1-2, 7-8

We will be starting capacitor circuits.  Check out the two videos below.  The first introduces you to capacitance, defined through the relationship Q = CV, where Q is the stored charge of a capacitor, C is the capacitance (measured in a unit called a farad), and V is the voltage difference across a capacitor.  In particular, you will see an old friend, Gauss's law, to find an E-field, then integration to find the voltage difference, and then a determination of C from the definition.

This video is
http://docvphysics.blogspot.com/2009/12/how-to-find-capacitance-for-each-type.html 

Next, capacitor circuits in series, parallel and combinations are similar to resistor circuits you already have done.  The rules are all similar, so check this out to compare and contrast R circuits to C circuits. Keep in mind that we have the same two rules for finding series and parallel capacitance, only flip-flopped for capacitors (compared to resistors).  

http://docvphysics.blogspot.com/2009/12/how-to-find-charge-on-capacitors-in.html

For Periods 3-4 Today

Check out the two videos about doing the integrals we began yesterday. The first is for a portion of a ring, so take notes and use this for your problem from last night.

http://docvphysics.blogspot.com/2012/01/how-to-do-non-gausss-law-problem.html

The second is for a stick.  Take notes on the sheet from yesterday.
http://docvphysics.blogspot.com/2012/01/how-to-do-non-guasss-law-problem-stick.html 

The quiz is moved to Thursday, so we can go over all this and others tomorrow.

A Synthetic Magnetic Monopole - Pretty Cool!

One of the great physicists of the 20th century, Paul Dirac, predicted in 1931 that there could, and probably should, be magnetic monopoles.  These are the analogues of electrons and protons, which carry a net electric charge, for magnetism - particles of just north or just south magnetic poles, unlike every magnet that has ever been observed, which is a dipole.  Many experiments have looked for magnetic monopoles over the past decades, but no evidence of them has been found.

However, a few days ago, a paper was published that shows synthetic monopoles could be formed using a Bose-Einstein condensate, that strange form of matter where bosons (particles with integer spin) can, when extremely cold (on order of nanokelvin), have such long wavelengths that they superpose and occupy the same quantum state.  It appears that by spinning this system and producing a vortex, a version of a magnetic monopole is formed.  This would revolutionize the hunt for monopoles because, now being able to isolate and study this synthetic version, one should be able to determine the properties and characteristics of monopoles.  Other scientists would then know the signature to look for in other experiments.

Keep in mind that in Dirac's theory, monopoles should exist because the implication would be electric charge must be quantized - it explains what we see with the electrical properties of matter.