With the conference and holiday season rapidly approaching, blogging might slip a little until the New Year, but I'll try to keep you up to date with physics of jet engines, baggage check systems, weather.
November 2008 Archives
I visited a company in Auckland yesterday, which involved negotiating the famous Auckland traffic. Now, I have to say that arriving in Auckland after the rush hour proved a very smart move, and we cruised to our destination without any fuss, but it got me thinking about traffic flow and physics.
Yesterday a very politely written letter arrived at the department, addressed to the physicists. I was curious as to what it was, and read it carefully all the way to the word 'homeopathy', at which time I began preparing a space for it in the 'cranky letter' folder of my filing cabinet. I will spare you the details of the 'discovery', but it concerned the physical reason why rainwater was safe to drink, and water-from-the-tap wasn't. The letter was even kind enough to suggest some experiments that my department could carry out to validate this discovery.
Many 'discoveries' of this nature turn up from not doing properly repeatable, controlled experiments. The orignal 'discovery' of Cold fusion in 1989 springs to mind. While I am quite willing to believe that this particular person 'recovered' from an illness after switching to rainwater for a drinking supply, I suspect that this had little to do with it. An experiment done once, with a sample size of one, doesn't make me down tools and rush off to investigate it, however revolutionary it might be.
Finally, my correspondent would probably be horrified to read of the link between rain and autism.
Have you ever sat in a lecture where an over-enthusiastic lecturer is waving his arms around excitedly, forgetting he is holding a laser pointer, and wondered what would happen if he accidently shone the beam into your eyes? Surely, you might think, the makers of laser pointers have anticipated such things. Well, last week I attended a training course on laser safety and I found out the answer, which, I'm afraid, isn't necessarily re-assuring.
The physics textbooks tell me that protons and neutrons are both made up of three quarks. These little things amuse me, because no-one has actually 'seen' one. (By 'seen', I don't literally mean seen visibly, but rather I mean some method by which a quark can be isolated and leave a tell-tale quark-signature in some way). But the real issue is that the quark theories tell us that we can't see individual quarks - they can only come in groups of three (such as the proton and neutron) or groups of two (the mesons). Trying to isolate one just doesn't work.
I got some new taps for my kitchen yesterday. The boring technical specitications on that bit of paper marked 'important - please read' said 'do not exceed a pressure of 800 kpa'. Now, leaving aside the fact that it should be 'kPa' not 'kpa', that means 800 kilopascals. A pascal is the pressure caused by 1 newton of force applied to an area of 1 metre squared. (1 newton of force is about the gravitational force on 100 g of mass). What 800 kPa translates to is the same pressure that you would get under a head of water eighty metres high. That's a fairly sizeable water pressure. But some places will could exceed that, for example if they were fed directly from a resevoir more than 80 metres higher than their house.
Incidently, the air pressure in the beam tubes of the LHC is a mere hundreth of a millionth (ten to the power of minus eight) of a pascal. That's the lowest vacuum that's ever been created, or, putting it another way, a tenth of the air pressure on the moon. That's low.
Since I'm talking about the Large Hadron Collider, I should tell you what a hadron is. Put simply, it's something that feels the strong nuclear force. Clear? Probably not, so let 's explain.
Last week I gave a talk on the Large Hadron Collider at the 'cafe scientifique' event in Hamilton. For those who don't know what cafe scientifique is, the idea is that a scientist gets to discuss some science to an audience of the general public in a public friendly environment (which means a cafe). And strictly no powerpoint allowed. Topics that are currently in the news work best, which is why the LHC was on the menu, and why it fell to me, a physicist, to do the talking.
Now, I am not a particle physicist (that's the sort of physicist who works with high energy particle accelerators). I believe I once said something along the lines that experimental particle physics is a complete waste of money because it has no earthly use for anyone. (And then the implication is that theoretical particle physics is also a waste of time, because there would be no experiments to back it up). But after doing some hurried background reading, perhaps my view has changed slightly.
My four-year old niece from Otago phoned her grandmother in Bay of Plenty:
"Grandma, do you have reflections in the North Island?"
"I think so dear, why?"
"Well, find a spoon and have a look."
Now, I think it most likely that niece was intruiged by the right-way-up / upside-down reflections from the convex and concave faces of the spoon, but she has also hit on an important issue in physics: are the laws of physics the same everywhere (and everywhen)?
No, before you hit 'close', this isn't anything to do with the election.
Last Saturday, I walked up Mt Te Aroha. For those not familiar with this part of the country, Mt Te Aroha is part of the Kaimai range, and rises majestically 950 metres above the Hauraki Plains, about 50 km North-West of Hamilton. Its bush-clad slopes are home to tui, kereru, parakeets, oodles of piwakawaka, and at least one feral goat, which I nearly tripped over. Anyway, I spent the following day wondering why I was so tired and hungry. Admittedly the tired bit had probably more to do with staying up to watch the election results, but the hungry bit is down to physics.
On the subject of luging, it is the perfect place to illustrate some physics. For those unfamiliar with the Skyline complex, the idea is you sit on a small cart and freewheel down a concrete path, negotiating the various bends inconveniently sited to slow your speed. Great fun, and lots of physics.
A month or so ago, my wife and I had a day of being tourists in Rotorua. While at the bottom of the Skyline Gondola, which takes people up to the luge tracks, I was accosted by a researcher carrying out surveys on tourism in the Rotorua region. Being a helpful sort of guy, I volunteered to do the on-line questionnaire on a laptop that had been set up just for the purpose. This was straightforward enough, with the only amusement coming from the failure of the system to grasp that any tourist could be spending zero nights in Rotorua, but the most fascinating thing was the conversation that ensued between the researcher and my wife:
I'm Marcus Wilson, a lecturer at the University of Waikato. Welcome to my Physics blog. PhysicsStop is where you can take a break from whatever exciting thing you are doing and read my take on the equally exciting physics that is out there in the world for all to enjoy. No, seriously, physics is not as boring as you think.