What's interesting about Brian's entry is that he talks about how a blog can trigger a discussion that increases the quality of the original posting.  Like peer review for a scientific paper, but informal, instantaneous, and more widespread. 

Read the comments attached to his posting, and you will see a great example of what he means.

Copper is probably better known, however, for conducting electricity rather than heat.  Its electrical conductivity is extremely high, and, coupled with its ease of working, there is no surprise that electrical wiring accounts for a huge amount of copper. 

These two facts (high thermal conductivity and high electrical conductivity) are not unrelated.  This is because the processes by which they occur are very similar. Electricity is carried by movement of electrons, and electrons are also a major carrier of heat. In copper, there are a lot of electrons that are highly mobile, and hence it has both high electrical and thermal conductivity.

In fact, in metals, the two follow (approximately) a simple relationship - the ratio of the thermal conductivity to the electrical conductivity is approximately proportional to temperature.  This is called the Wiedemann-Franz law. One can 'derive' this relationship using some fairly simple hand-wavy physics arguments, though to do it properly is not so easy. I'll be doing the hand-wavy approach (for those that want to know, it's the Drude theory) with my second year students soon.

I am sure this will come as welcome news to many researchers, particularly the many PhD students who have had their student loans accumulating quietly while they have had no results to process.

You can follow all the action on www.twitter.com/cern

P.S. Utterly unrelated to the above, I accidently discovered earlier in the week that if you hit the 'Windows' button and the 'M' key at the same time on your computer keyboard it minimizes all your windows.  Maybe I was the only person in the world not to have known this, but, in case I'm not, I thought I'd share this essential piece of knowledge with you...

It's of fallstreak cloud, and this example was spotted by my mother-in-law, Barbara Seccombe, off the coast from New Plymouth recently.  (Photo credit to my father-in-law, Wally Seccombe, used with permission).

It's not something you see everyday, so I asked my brother (Damian Wilson), who is a meteorologist in the UK, for an explanation.  (N.B. - would-be meteorologists take note - you should be studying physics...)  Here is Damian's explanation, used with permission (It's great when you can get other people to write your blog for you ;-)  thanks guys!)

Putting it in the fridge for several hours will do the trick. But it's quite slow. Putting it in the freezer would cool it quicker, but we don't want the outside frozen while the inside remains warm. So what about a combination of the above - putting it in the freezer for a while, then transferring it to the fridge.

Now, I have to say I don't know the answer to this. The combination freezer-fridge method seems on the face of it to have some merit - get the outside really cold as quickly as possible, then let that cold help bring down the temperature of the inside, while, at the same time, letting the outside rise a bit.

But a second thought says that the distance heat (and cold) penetrates into a substance in a given time depends very much on the thermal diffusivity of that substance.   To penetrate a few centimetres of orange is going to take a given time (approximately the distance squared divided by the thermal diffusivity), no matter what you do to it (except drilling holes in it and pouring liquid nitrogen inside).

So I don't have an answer. (It sounds like a nice investigation for a science fair project to me - get a nice big orange and stick thermometers into different parts of it - N.B. please don't ram mercury thermometers into anything - you DON'T want mercury all over your kitchen bench).  But I do know that the question isn't as trivial as it might sound.  I remember several years ago reading a research article looking at the mathematical modelling of the penetration of burns/scalds into the skin.  What matters here is things like the temperature of the hot object, how long it was in contact with the skin, the area of contact, and how long it was before the patient got the burn under running cold water (and how long they held it there for).  I think the idea of the article was that knowledge of these things would help medical staff make decisions on treatment options.

I could, I suppose, do some mathematical modelling of heat transfer in spherical volumes of water (i.e. oranges), which isn't going to be too taxing for a theoretical physicist.  But I'll leave it to those who like experimenting to give it a shot and tell me the answer...

The spinning earth posses something we physicists call angular momentum.   It is the 'spinning' version of linear momentum;  the latter being the product of a thing's mass and velocity.  Linear momentum  is a measure of how difficult it is to stop the object by applying a force to it - things with a lot of momentum take a lot of force or a lot of time to stop. Likewise, something spinning with a lot of angular momentum will take a lot of torque, or a lot of time, to bring to a rest. Also, something spinning with its mass distributed far from its axis (an ice skater with her arms outstretched) has greater angular momentum than something spinning with the SAME mass and SAME spin rate,  but with its mass distributed close to the axis (an ice skater with her arms pulled inwards). That's because it has greater rotational inertia.

In the absence of external forces, linear momentum is conserved (Newton's first law); likewise in the absence of torques (that is, a twisting force) angular momentum is conserved. Thus the earth keeps spinning, on its own axis, once every 24 hours.

Except that the earth CAN change its spin rate, and its axis of rotation, if somehow the way its mass is distributed moves. This is what appears to have been measured following the Chile earthquake. The movement of the plates appears to have caused a change in the way the mass of the earth is distributed. The movement of one plate under the other has caused a net movement of mass towards the centre of the earth. This gives a decrease in the rotational inertia of the earth, and, as a result, the earth's rate of spin has increased. Note that angular momentum is conserved here.

It's the earth-equivalent of the ice-skater increasing her spin rate by pulling her arms in.

How much has the day changed by?  Only about a microsecond.  Not something that you are likely to notice.

First Example.  The Rydberg constant relates the spacing of spectral lines due to electronic transitions in Hydrogen.  Its 'accepted' value (from the CODATA committee) is 10973731.568525  per metre, with an uncertainty in the last digits of 73.    That means, the committee is reasonably confident the true value lies between 10973731.568452 and 10973.568598 per metre.   That's a staggeringly small uncertainty, about one part in ten to the power  11. (One part in a hundred billion).  

Second Example. Newton's constant of gravitation (Big 'G").  This constant describes the gravitational attraction between two masses.  It is very difficult to measure in the lab (still, we get our second year students to have a go) because its effect is easily swamped by other things. Normally, of course, we never take any notice of the fact that our cup of coffee on the desk is attracted by gravity to the textbook next to it - the effect of them both being attracted to the earth below, which is so much more massive, swamps this.   But the attraction between two nearby objects CAN be measured.

The CODATA value for G is 6.6742 times ten to the power of minus 11 metres cubed per kilogram per second squared, with an uncertainty of 10 in the last digits.  That is, its value most probably lies between 6.6732 and 6.6752 times ten to the power of minus 11 metres cubed per kilogram per second squared.   This uncertainty is about one part in ten thousand.  It might sound small to you still, but this is the best value that physicists have ever come up with, based on several very carefully done experiments.

 Another problem with Newton's constant of gravitation is that there is no theory linking it with anything else in physics.  Gravity sits apart from other forces.  For example, we have known since Faraday's time the connection between electricity and magnetism, and, more recently, the connection between the electromagnetic forces and the weak nuclear force that acts in the nucleus of an atom. But, despite the efforts of people like Einstein, gravity still sits excluded. It really is a strange phenomenon.

For more information on the fundamental constants, see http://physics.nist.gov/cuu/Constants/index.html

If you want details of how things are measured, have a look at the rather technical paper of Mohr et al (2007) http://physics.nist.gov/cuu/Constants/codata.pdf

It uses electronics made from organic compounds that has been 'printed' onto a plastic surface. The result is a flexible, drop-proof screen.

It's another example of how physics research results in end-products; not by way of a short-term investment payback to a funding body,  but in the long term. The research behind the Que started over 20 years ago.  Twenty years ago, how many would people have seen the current market for portable, flexible, pdf readers as existing? Given the pdf didn't exist until 1993, probably only the really visionary ones.

Or, are the deaths of two former University of Manchester academics from pancraetic cancer just co-incidental?

Maybe the NZ government needs to evacuate the whole of Christchurch...

I've been asked by a reputable  journal to review an article (let's call it 'A') as part of the standard peer review process.  What are my thoughts on its content and quality, etc.?   Now, I have a look at the article in question and I find that the authors refer heavily to another article (let's call it 'B'), in a journal that I haven't heard of.   Thanks to the magic of the internet, I quickly retrieve 'B', and have a look at it.  No problems so far, but I'm now interested in finding out a bit more about the mysterious journal in which it is published.

The mighty Google works a treat - not only do I find the journal's website, but, more interesting, up comes a lot of links to blogs where this journal's name is used in the same sentence as 'quack' and 'pseudoscience'.

Now, here's the problem. My job is to review article 'A', not article 'B'.  My review of 'A' should be on the merits of article 'A' alone. Shouldn't it? The fact that the journal where 'B' appears has been discussed in a fairly savage light on many science blogs should not influence my thinking as to whether 'A' is a piece of quality science. (?)  After all, blogs are not necessarily reliable (Says he who is writing a blog) - but they are in a sense 'peer reviewed' - that's what the comments do.

 So, what should I do?  Decline to review the article? But that just passes the problem to someone else. Try to get one bit of my brain to ignore what another bit knows? Tricky one this.

I suppose one thing it shows is how difficult it is for anyone to make a truly independent judgement about anything.  Any background knowledge starts to influence the way you see something.