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March 2009 Archives

My last comment on powering transport has prompted these thoughts:

Will Google Earth one day become so packed full of data that you can 'visit' somewhere from your own living room and get 99% of the experience - thus doing away with expensive plane trips to exotic destinations?

But will the demands on your computer system be such that in order to get that experience you will have to consume as much energy (presumably through electricity to your computer) as you would by getting on an aircraft and actually going there?

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Buried in my junk mail this weekend was a catalogue containing all those gadgets that might come in handy once in a lifetime - you know the sort - solar powered tea strainers and personalised tin-openers - that kind of thing (I must get some to give out as Christmas presents...) 

One was a water-powered calculator. I haven't seen that kind of thing before, and I'm guessing it must have some kind of fuel cell arrangement exploiting the gunk in tap water to produce a chemical reaction that gives enough current to operate the calculator.

Anyway, the issue was not that it 'ran' on water, but that it claimed to be 'battery and electricity free'.  Techinically a fuel cell isn't a battery, so that one might be OK, but electricity free? Ummm. Bet it contains lots of integrated circuits. What do they run on. Water?

 

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In the last few days I've been wrestling with one of the unsolvable problems of physics, namely that it is impossible to measure something without changing it.

Here's an example. Suppose I want to measure the temperature of a pot of warm water. I can do it by putting a thermometer in it. Now, since the thermometer has been sitting out in the kitchen, it is colder than the water, so when I put it in, a small amount of heat from the water flows to the thermometer. The thermometer heats up, and the water cools down slightly, until they reach the same temperature. The temperature I record is then the temperature of the water now, but not the temperature of the water before I put the thermometer into it. So the act of measuring it has changed it.

 

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Here is an amusing little comment at the end of an otherwise depressing article about the dire state of our early childhood education:

'Deputy principal Shevaun O'Brien said 19 of 36 of the school's new entrants rated below average last year.' (Kay Blundell and Rebecca Palmer, Dominion Post, retreived from stuff.co.nz today. Link to article here.)

19 out of 36? That's about half isn't it? And what is the meaning of the word 'average' ? Approximately the mid point. So half the children were below the mid point. Hmmm. Doesn't sound all that shocking to me.

Reminds me of the George W. Bushism: "I want every American to earn above the average wage".

(This sort of comment arises because the word 'average' has come to be synonomous with 'acceptable', and 'below average' synonomous with 'not up to standard'.  An example of the drifting English language. Which is one reason why, in physics and other science, we stick to very precise words, such as 'median' and 'mean'.)

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Last Friday (for most parts of the world - Saturday for us 'advanced' people in New Zealand) was the equinox. Loosely described, that's when the day and night are of equal length - from this moment on and for the next six months all us southern hemispherers will be experiencing longer periods of darkness than daylight as we head into winter, while the northern hemisphere types get to laugh at us while they cruise into summer. Come 22 September (or 23 for us awkward people at the leading extremity of the time zones), we'll swap round again.

Did you spot the deliberate mistake? I said it is six months between the two equinoxes. That's approximately true, but not exactly. Count up the days, you'll get 186 from the March date  to the September date, but just 179 from the September equinox to the March one.  Put it another way, us unfortunate southern hemispherers have to endure an entire week more 'winter' than do our friends in the north. (Northerners would say it's our punishment for hogging all the best features of the night sky, but that's another subject.)

 

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This one from Reuters has a familiar ring to it.

Great to know that the world's armed forces are in such control of their major assets.

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Thinking back to last entry, I think the way the physicist thinks makes him (and I'm sorry but 'him' is still about 90% correct) quite versatile in terms of problems he can address. I've been exchanging emails recently with an economist, with a view to having him speak at cafe scientifique. What has economics got to do with science, and physics in particular?

The large merchant banks and financial institutions  fall over themselves to recruit physicists. (Well, probably they're not recruiting anyone now, but when they did, physicists were certainly a target.) One of my fellow students (a New Zealander, incidently) in Bristol, UK, where I did my PhD, was snapped up by a large London financial institution.

 

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Semester has been going just over two weeks here at the University of Waikato, and I'm getting back into the swing of teaching after the summer break. One thing that struck me today, while thinking about my lectures, was how much I use analogies while teaching physics.

That's maybe not all that surprising, since physics is full of analogies. A much used one is the similarity been water flow in a pipe and electricity. In this case the flow rate of water (litres per minute) is analogous to the electrical current (amps) - electrical current being a flow of electrical charge. And the pressure of the water (pascals, or Newtons per metre squared, or psi in old units) is analogous to the voltage.

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On the back of my Memphis Meltdown icecream:

"Warning: Do not conduct aspects of nuclear physics or complex surgical procedures whilst consuming this product"

You what?  Just how is one meant to "conduct aspects of nuclear physics?" Is "Aspects of Nuclear Physics" some lesser-known composition by Wolfgang Amadeus Mozart? I can see it now - Sir Simon Rattle standing in front of the Berlin Philharmonic Orchestra - baton in one hand, Memphis Meltdown in the other, and first violins taking evasive action against airborne milk product.  Little wonder the need for the warning.

OK - so I get the joke - they want to say that the icecream is dangerously tasty, or something like that. But it does irk me that yet again we see 'nuclear' being associated with 'dangerous'. True, nuclear weapons are pretty dangerous things, but there's a whole raft of nuclear stuff that is anything but.

What about the radioactive source in your smoke alarm (shock, horror - yes you have one in your house) - that's there to alert you to danger not to cause it. And then there is medical physics - with its radiotherapy, PET scanners (nuclear stuff) and MRI ( 'nuclear' magnetic resonance imaging - except the 'nuclear' bit has to be left out so people don't get scared). These are fantastic applications of nuclear physics and we have physicists to thank for them.

So please, advertisers, less of this 'nuclear is dangerous' stuff.

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I had dinner last night with a group of my wife's friends - mostly health workers of one flavour or another. One explained how she is involved with developing strategies by which the health system can cope with the demographic time bomb - when in twenty years time a considerable proportion of the population will be retired, and a significant proportion of those will require nursing care to varying degrees.

She then threw into the conversation the fact that a New Zealand university (that will remain nameless) has developed a robot that will attend to the needs of the elderly. Now that rather scared me. Growing old is hardly  a pleasant thought as it is - with the chance of needing someone to attend to both ends of my digestive system in my later years - and I wouldn't exactly feel inclined to let a robot do it.

 

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Methinks swimming in the outdoor pool is over for this summer. I emerged from the pool at lunchtime feeling that I'd just spent a day in Antarctica. I'm told that the peak daily temperature has now dropped to about 22 degrees.

Twenty-two? It doesn't sound that bad. If the air temperature were 22 it would feel quite pleasant. So how come it feels so much nastier when you are in the water?

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It's amazing what you can see on Google Earth.  Take a look at the sea around the Raglan to Kawhia coastline, for example.

You can immediately see why it attracts surfers - on the day the current satellite image was taken, there was a near-perfect set of waves rolling in off the Tasman. There's a lot of wave effects you can make out on this image.

Out at sea, the waves are about 300 m apart, but closer to the shoreline they become closer together. That's simply because deep water waves slow down as the depth of the sea reduces - since their frequency (the number of waves per second) remains the same, their wavelength (distance between the crests) has to reduce. You can see this effect beautifully at the entrance to Aotea harbour.

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In the minds of many, the name 'Large Hadron Collider' is linked with the words 'Higgs Boson'. And so it should be - one of the aims of the LHC is to find (or not to find) this mysterious particle. But what is the Higgs boson?

It's to do with mass. In broad terms, mass is a measure of how much matter (or 'stuff') there is in something. In the everyday world, it is possessed by protons and neutrons, with a small contribution from electrons. In physics, there are really two things that mass does - first, it provides inertia, meaning the more mass something has, the harder it is to get it moving (and the harder it is to stop it once it is moving); secondly, it interacts with a gravitational field (massive things are heavy).  Just how or why these two roles are linked is one of the unsolved mysteries of physics.

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I gave a talk to the Hamilton Astronomical Society last night on the Large Hadron Collider. It was all very topical back in September, when it was 'switched on', but following its breakdown soon later it has rather faded from the popular press. So what is happening now?

The simple answer is that it is still under repair. The troublesome cooling system is still being attended to, and, in fact, CERN have taken the opportunity to carry out some previously scheduled maintenance work at the same time. The currently scheduled 'switch on again' date is September this year - a whole year's delay. They hope to be getting data-generating collisions by the end of October. (Link to latest press release).

So you have a bit of time breathe easily, knowing that the world will not end again for another few months at least.

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