Proving the Obviously Untrue - STEM

Crashing Cars

nospam@example.com (Colin Turner) — Thu, 11 Dec 2008 10:27:44 +0000

Consider two identical cars, each travelling at a constant velocity v towards each other. Suppose that they crash, and to simplify things, let's not consider any rebound. Then the energy of each is kinetic in nature and so the energy of the crash is given by

Ok. That's a nice way to show the energy of the collision goes up with the square of velocity. Now, according to the principle of relativity this should be an identical situation if you consider it from the reference frame of one of the cars. In that case, the car you are looking at has a velocity of 0, while the other car has a velocity of 2v. Now the total energy of the crash looks like

So. Why the discrepancy?

Einstein and Eddington

nospam@example.com (Colin Turner) — Tue, 25 Nov 2008 19:31:35 +0000

On Saturday night, quite by accident, I sat down to watch "Einstein and Eddington" on the BBC. Einstein has been an inspiration to me from an early age, and I'd known a lot about his life and work, and for many years a picture of him has adorned my room or office, though not at the moment as it happens. I suppose in compensation einstein is the hostname of my work computer at the moment.

Anyway I was also for this reason aware of Arthur Eddington, and his famous experiment to verify that gravity bent starlight. I was also aware of his famous quote regarding being one of three men who understood General Relativity. Nevertheless, it was fascinating to see the historical context of the interaction between these men, and a bit more of Eddington's life. I would recommend the programme highly, so if you're in the UK you have a few more days to catch it on iPlayer.

Great performances from Tennant and Serkis.

In 2008, you might still need to lie about your OS

nospam@example.com (Colin Turner) — Sun, 28 Sep 2008 21:09:12 +0000

Today my sister-in-law, Siobhan, asked me to help her debug her brand new Sky ADSL set-up. She told me her PC, with a wireless adapter, was connecting OK, but she couldn't get onto the internet at large. I was relieved I had decided to throw my laptop in my bag when I came down to visit as that would make the whole thing a lot easier. I went up to the house, opened my laptop and in a few seconds it was ready from hibernation (into Debian). Very quickly we identified the wireless network, put in the passphrase, and got connected straight away.

So the wireless was working OK as it appeared, and all attempts to surf elsewhere failed. I surfed to 192.168.0.1 and was rewarded by the router login screen, I recognised it as a Netgear device, but the usual netgear "admin" and "password" didn't cut it. Google, via my N95 supplied that "admin" and "sky" was the answer. Result, I was in and could see that there was an IP allocated to the router. I did some pings from my laptop, and found that the packet loss was almost, but not always, complete, and that sometimes DNS worked, sometimes it didn't. All my nice tools in Debian made the diagnosis easier. At this point I was assuming a line problem and that the speed would need to be restrained.

So, I hooked the laptop to the router directly with a cable, just to rule anything else out, and because I knew the tech people would fret about it needlessly, and I saw the router kept losing it's connection periodically - it would stay up for minutes, but nothing useful could be done with it then. So, it was time to ring the dreaded helpline. Siobhan had to go through the usual Q&A, including some quizzing about how her name was spelt, and then I was placed on the phone to speak to the tech-girl as it happened to be in this case. I tried, politely but fairly deperately to short-cut the endless questions by outlining what I had already discovered. She asked me if I was using Vista, I said "No, Linux", so she asked again if it was Vista or XP, and I said it was neither, it was Linux, but that the problem was between the router and their operation somewhere. So we got put on hold for about 5 minutes, and already I had the feeling of dread - I should have just lied. She came back on the phone and told me that her colleagues said Linux wasn't supported and I'd have to use another OS so she could talk me through settings.

With now rapidly mounting exasperation I explained I was already connected to the router, both on the network and with a browser, could clearly see the outbound connection going up and down like a yoyo, and that rebooting into another OS would make absolutely no difference to the problem, but of course, she was adamant, so with great irritation and reluctance I rebooted into Vista, waited for it to finally sort itself out, logged in and ... the phone line went dead.

So now, punching the floor with irritation, I ask Siobhan to phone back, get through the maze of keypresses and introductions and we get the second person. She wants to start at the beginning, but we try hard to get her to understand what we have already found. She at least seems to understand it's not an OS problem. She tells me to try another microfilter, I say fine, but I obviously can't do it just as we're on the phone, she says "That's correct, you would be disconnected". Well... yes, I got that. Anyway, we go through a few other gems and I anticipate her asking me to unscrew the BT master faceplate and plug things in there.

So we do that, with little hope, it doesn't work. I curse Vista as I try to navigate IE (I don't even dare use firefox in case they moan about that). Again, we call, the same procedure, the third person, who talks to Siobhan only, and is happy without further technobabble, to finally redirect us to the "Solution Centre" or some such. Siobhan begins to talk to operative number four, and passes me over.

Joy... She understands the problem is at their end, she limits the speed on the connection, just like that it all starts to work. I thank her profusely and say it's a pleasure to finally get to someone who doesn't ask me to check if I have an electricity supply. She comes from Northern Ireland too, we share a quick laugh about it all, she helpfully suggests that she'll leave the ticket open while we check over the weekend the new "fix" is stable. Yes, I know I can be a grumpy old [whatever] about it, and that the tech people often have to speak to people who don't have a clue what they are doing, but it is exasperating when they can't go a little beyond the script to realise you might actually know how to help them fix your problem.

Way back in the early days of ISPs in Northern Ireland I found some problem, carefully excluded local causes and called the ISP to report it to them. Foolishly I told them at the time I was using WAN and LAN at the same time (Netware), to which they promptly told me that was impossible and refused to discuss the problem further. I pointed out that not only was it possible, it was all working nicely in the morning. So I called back and just lied that time.

The moral of the story seems to be, when someone asks if you are running Vista, just say "yes".

Email Latency

nospam@example.com (Colin Turner) — Mon, 02 Jun 2008 13:17:38 +0000

Like lots of people who are too hooked into technology for their own good, I tend to receive loads of emails a day, even after the huge quantity of spam is removed. Sometimes it's easy, and fast to respond to a given email. Once in a while I get an email from someone that I really want to respond to in some detail; usually an email from a good friend I don't often see or haven't seen in a while.

Since I'm usually up to my neck in too much stuff, it's precisely this email that I leave to the side to deal with later, "when I have more time". Yes, the people who know me well already understand the problems with that. It would help if icedove stored its tags correctly in my dovecot based IMAP server. but for some reason it often doesn't. The end result is that "later", I'm still struggling to complete a dozen tasks on a list, and the email is anonymously buried in my inbox under many more recent arrivals.

That's really not good, and I'll have to make more of an effort to keep in touch with all these friends.

Runs on mailing lists

nospam@example.com (Colin Turner) — Mon, 26 May 2008 20:31:59 +0000

Today I spent the day at the chemistry department in Edinburgh University demonstrating (at their invitation) OPUS with Ron Laird. I frequently receive these sorts of invitations, and that's nice, but it's a whole day to go there and back again.

I got home and checked my email, and saw dozens of emails about a conference in Japan. It seems the organiser thought it would be a good idea to set-up a mailing list, but hadn't configured it to be read-only. Ok, a pain, and basically spam. Now the real stupidity sets in, when several people start to mail the list to ask to be removed. Ok, more annoyance. Now we get the real fun, computer professionals sending "unsubsribe foo@bar.com" to the list (not the list server) so we all get to enjoy that.

I've noticed this cascade effect before, when people start doing this and everyone else gets fed up and starts repeating the mistake, so want off the list; a bit like a run on a bank. But, please people, email the originator of the spam, not the list and/or look in the list control lines to find out how to unsubscribe.

Battlestar Galactica near Earth

nospam@example.com (Colin Turner) — Sat, 26 Apr 2008 22:08:09 +0000

I have to say, I've enjoyed the "re-imagining" of Battlestar Galactica immensely so far. When it first aired, I thought it was a pretty corny idea, and didn't watch it, but I watched an odd episode here and there, and I began to realise that this was probably the most slick, dramatic, special effects laden sci-fi show yet. It's very addictive, and one of the very few TV shows I feel I don't want to miss an episode of.

Tonight I just sat down to watch season 4, episode 3 (no spoilers, don't worry!), and was very gratified to see Cylon base ships moving in a background that contained Orion, absolutely no doubt about it, a nice touch to show Earth is near. Now Orion is the easiest constellation to see, and I admit I never paid attention to the background before, but it's just that kind of nice detail I like about the show. I'll keep looking for more constellations now!

Wheeler goes through the last event horizon

nospam@example.com (Colin Turner) — Fri, 18 Apr 2008 09:52:58 +0000

This week, John Archibald Wheeler died, from pneumonia at the age of 96.

Wheeler was a spectacular physicist, who worked in the areas of General Relativity among other areas, he is the guy who popularised the words "black hole" and "wormhole", and worked with Einstein in his last years. I hadn't known that he had worked on the Manhattan project, and that unlike other scientists, didn't regret his role in the project but merely the fact that it didn't save his brother's life. I also hadn't known that he supervised one of my other great physics heros Richard Feynman, but I was impressed with his work even before that.

I met his work when I was about 15 or 16. My maths teaching at secondary school had been, well, uneven to say the least for the first few years, but I got a good teacher in 4th and 5th form, Ken Brown. I started to realise that mathematics made logical coherent sense and that if I worked a bit harder I could get on top, and then understanding the next bit took little effort. I also found that, even with this basic mathematics, I could understand a lot of Special Relativity which fascinated me, but not so much as the General theory. In our local library in Bangor I found the book Gravitation by Misner, Thorne, and of course, Wheeler. Now, my memories of this book are old, and I don't have a copy, but nostalgia almost prompts me to buy one. But I can remember my impression of the book.

It's not a layman's account, although there are many good examples of that, but it is beautiful, the illustrations, the mathematics, I enjoyed poring over all of it, and I think I did come to understand the theory better for it, even if the bulk of the material was beyond me then. It inspired me to study physics, and mathematics, and although when I reached university the mathematics itself began to captivate me more than the physics, still, two of my final year modules were Quantum Mechanics and Tensor Field Theory (the mathematical basis for General Relativity). In fact, I picked these out as modules I wanted to do when I was in first year, and planned everything around them. In the end I am more of a Pure Mathematician, and though back in school I always wanted to work on GR I guess it's very unlikely I now ever will, it was an inspiration to me, and people like Einstein, Feynman and Wheeler showed the way.

My Old UFO sighting

nospam@example.com (Colin Turner) — Tue, 15 Jan 2008 12:10:01 +0000

I promised previously, when talking about UFO sightings over Bangor, that I would record my own here.

As I mentioned then, this doesn't imply alien craft, but an unidentified flying object, and I'll pretty certain this wasn't such a craft, or if so, the pilot probably needs an extensive driving ban. Anyway, here's my record from my log book at the time.

Date: 26th September 1991, Observers: Myself, Dad, Tom Nelson
Seen: Saturn at 117x, Seeing: II, Transparency: Very Good

Saturn seemed exceptionally clear but broke up at 166x. It is descending further into the south of the sky. A 17 day old moon foiled another attempt at M31.

I noted a series of about 6-10 flashes from 10:00 pm to 10:25 pm. I was one of the "objects" at about 10:20 pm. About 3-4 Hours Right Ascension, 60 - 80 degrees Declination. It looked like a wobbly meteor with a flash easily magnitude, say, -2 or brighter. Saw another at 10:30 pm. No further flashes. Could have been an astronomical event or some domestic problem.

My sketch from the night

I'm glad I recorded this carefully. The then president of the Irish Astronomical Association (of which I was a member then) was from Bangor, and was laughed at for his similar report, so it was helpful to have some more evidence. I still don't know what I saw, it was very bright for a meteor, and of course, they should go in a straight line. I have speculated that there was a rupture in the side of the object from which gas was venting, perhaps causing it to travel in a helical path which would have looked "wobbly" from my perspective on the ground. You can click on the thumbnail of my sketch at the time to see my sensational artistic talent.

A* on A levels

nospam@example.com (ct) — Sat, 18 Aug 2007 15:22:26 +0000

With apologies to Spinal tap...

P1. The A level is a great qualification, and it's going to get even better, they are going to introduce the scale up to A*.
P2. A*?
P1. Yes, how cool is that? All other qualification only go up to A.
P2. Hmm, but wouldn't it be easier to just call the A* an A and use the scale that way?
P1. [blank look] but it goes all the way up to A*

etc.

UFO does NOT mean flying saucer

nospam@example.com (ct) — Mon, 14 May 2007 17:25:44 +0000

Ok, it's another pet peeve posting. The BBC have just posted a story about strange lights seen over Bangor. The summary reads "Residents in County Down have raised the possibility of a UFO sighting above the skies of Bangor." It's not a possibility, it was a UFO sighting. That is, they were Unidentified Flying Objects. It irritates me when people use UFO to mean "bizarre alien craft about to abduct me", because that would clearly be a well identified flying object. On another note, I lived in Bangor for many years and I also had a UFO sighting when I was there. I was in the back garden with my telescope watching Saturn, and was vaguely aware (I had one eye shut, the other to the eyepiece of my 8" telescope (SCT)) that there odd lightning like flashes going on. I was watching the sky for a while then, and was lucky enough to see one right in the centre of my vision. It was a very bright corkscrew like motion that lasted about a second. I shouldn't rely on memory, if I remember I will dig the details from my observation notebook.

"Anyone can teach maths"

nospam@example.com (ct) — Sat, 24 Mar 2007 09:08:38 +0000

How many times I have heard this quote. I beg to differ. I was on my way home from work yesterday, listening to BBC radio 2. A woman was on making a music request.

The presenter (Stuart Maconie) asked her what she did for a living.

Woman: "I'm a teacher"
SM: "What do you teach?"
Woman: "Maths"
SM: "What were you teaching today?"
Woman: "Maths" (Duh)
SM: "No, I mean, was it quadratic equations or something?"
Woman: "Yes, actually..."

More chatter...

SM: "What's the volume of a cone?"
Woman:

More chatter...

SM: "What's the volume of a sphere?"
Woman:
SM: "They can't both be that"

Yes, that's right, they can't both be that. That would be because both answers are totally wrong. Not only are they wrong, they are not even dimensionally correct. In other words, any formula that represents a volume has to essentially be a distance times a distance times a distance. Count them, three distances multiplied together. This idiot gave the formula for an area; so it's not just the incorrect formulae that bothered me, or the fact that this was a maths teacher, but the fact that the formulae couldn't possibly be correct. Anyone with some insight into mathematics would know that. I would have known better when I was 18. Now there are some excellent maths school teachers, doing the job for the love of it, because it's certainly not for the pay, but there are some awful ones too, I know because:

I had one of them;
my daily job largely consists of undoing the damage they have wreaked on my students.

Of course, she was probably caught off guard, as if that's an excuse for not knowing these formulae if you're a professional mathematician, but in that case the correct answer was "I don't remember". Argh! Ok, I feel a bit better now. Oh, the correct formulae are of course for a cone (note, , three distances) and (note, , three distances).