Sunday, July 29, 2007

The psychology of marking

So, how do you mark work then?

Yes folks, it may be the holidays but nevertheless I found myself marking a pile of homeworks this morning... if this sounds like dedication, then it's not really; more a case of not having got round to doing it during term-time.

Anyway, it struck me that marking a pile of jotters can be done in many different ways. It's almost like the Cadbury's Creme Egg "how do you eat yours?" advertising campaign.

Confused? Well, let me explain. You may think that teachers simply mark the jotters in the order that they have the jotters in, which will probably be rather random (having been schlepped home first). But not necessarily. When I first started teaching I was given the advice to try and mark the best homework first (ie dig out the work from the pupil you consider the best) as this is a good way to check that you haven't made any mistakes in your marking scheme. Good advice. But... this may mean that you end up penalising rather minor errors (we dont' want anyone do get 100% too easily, do we?), and then when you get on to weaker pupils you're then struggling to give many marks at all. So care is needed.

Nowadays I do actually mark jotters more or less as they come, until I get down to the last ten or so. Then I have a quick look through the names of those remaining, and save a few good ones for the end. I like to finish on a high note...

I've heard of other equally idiosyncratic approaches taken by maths teachers, and am happy to hear of any more. Own up now to your petty foibles!

(I haven't mentioned here the modern approach of "mark less to achieve more", or "comment only marking". Blimey but I have reservations about this. Apparently when (for example) a pupil makes an error in calculating a gradient, I'm not meant to mark this as wrong, but somehow at the end of the piece of work I'm meant to make some kind of constructive comment instead. Aye, that'll be bloody chocolate!)

Saturday, July 28, 2007

Maths Teacher Goes to the Movies: The Simpsons Movie

Finally, a movie that isn't a sequel... er, except I suppose it is of sorts.

How's the movie?
Well, I enjoyed it, but the bar is set pretty high when it comes to the TV show, so I can't help but feel a tad disappointed overall. I mean, it's way funnier than Shrek the Third, but you'd expect that. Plenty of laughs but oddly enough it ends up being the plot that gets in the way, particularly towards the end of the movie. And why so few guest stars? Overall it feels a little like a single episode stretched out, and I'm absolutely certain that the TV show could "do" this plot in 20 minutes, and that it would be more enjoyable for it. By all means go see it, but there are times it's a bit... meh.

Then again maybe I'm being too harsh. It may well be the funniest movie I'll see all year. And they still manage to have a go at Fox Television. But maybe that's part of the problem: the TV show is brilliant at playing with and subverting the medium of TV (if you will), whereas the movie doesn't do the same for the film medium, excepting gags at the start and close of the movie. (One word of advice here: don't leave until the credits have finally finished or you'll miss hearing Maggie's first word - a very funny moment.)

How's the maths
Well, there's an amusing example of Arnold Schwarzenegger coping with very basic arithmetic - encouraging to see he knows that if you double two, you get four.

Can I teach with it?
A large part of the plot concerns a dome placed over the town of Springfield, so there's a few opportunities to pose questions on hemispheres, and maybe even centripetal motion if you're feeling really brave. But the most interesting thing here is how direct proportion doesn't apply: the movie is roughly equal in length to three TV episodes, but I can't help feeling there's more laughs to be had in the latter than the former.

Overall score?
Well, bear in mind it's always difficult to be precise when giving movie ratings, and that any attempt to quantify creativity or enjoyment is doomed to failure... so overall I give this movie e + 1 out of five stars, which rounds (up) to four stars.

Friday, July 27, 2007

Two pi or not two pi?

Hmm... this is interesting, though it's been linked to by others far earlier than me. Basically the author points out that way back when it was decided to define pi as being 3.14..., we would have been much better off defining it as 6.28..., that is to say, two times our value of pi. Apparently a lot of formulae would work out looking a whole lot neater if we did, and radian measure would be much easier: 360 degrees would be pi radians (whole circle = all of the pie!); 180 degrees would be pi/2 (half circle) etc... I can see the attraction. Though it wouldn't clear up the misconception that many students have, when they suddenly decide that pi equals 180 in the middle of an integration question involving trigonometry.

Of course the actual definition of pi as a ratio would need tweaking, but that would be easy enough.

Oh well... missed opportunities, eh?

Thursday, July 26, 2007

Maths Teacher Goes to the Movies: Harry Potter and the Order of the Phoenix

Yup, I'm on a roll... shame that it's such a summer of sequels though.

Anyway, on we go for Harry Potter and the Order of the Phoenix, or HP5 if you prefer.

How's the movie?
Well, you know what, I quite liked it. Very dark and not much in the way of action until the end, but I thought the director caught the atmosphere of the book well - and additional kudos for keeping the running time down, given that HP5 is the longest of all the books by some way. Imelda Staunton completely runs off with the film for her performance as Dolores Umbridge - impressive to end up so scary whilst wearing pink - whilst the lead actors acquit themselves pretty well. I mean yes, of course they look too old, but we're well into suspension of disbelief territory here anyway, so I can go with it.

The weirdest thing of all for me was seeing the film in an old style cinema which insisted on having an intermission... very much not appreciated.

How's the maths?
In Harry Potter? Are you serious? A shame I suppose not to see "Harry Potter and the Simultaneous Equations of Doom", or indeed to ever meet a maths teacher. Do they even have them at Hogwarts? Maybe Snape teaches sums in his spare time...

Can I teach with it?
Back to sequel-itis here. You could compare the length of each movie with the respective length of each book, I suppose, and see if there's a connection. This could be as simple as drawing some nifty bar charts, or (further up the road) as complicated as doing a statistical test like the... um... can't remember which one would work... the ummm... "hingummy" test, perhaps?

Overall score?
I'm happy to award the movie four out of five stars (two stars from Gryffindor and one each from Hufflepuff and Ravenclaw - no stars at all from Slytherin, obviously).

Wednesday, July 25, 2007

Maths Teacher Goes to the Movies: Shrek The Third

(oh that it should come to this...)

Well, heck, what else is a maths teacher to do with their holidays?
And besides, who says maths teachers can't take an interest in popular culture? (I mean, who else kept the fashion flame burning for cardigans and corduroy jackets, if not us lot?) So every now and then, I'll be offering some movie reviews - from an educational perspective, obviously.

How's the movie?
It's fine. It's been pretty harshly reviewed as far as I can see, so I did go in with low expectations. But if - like the good Doctor Mark Kermode of Radio 5Live - your measure of a comedy is that it should make you laugh out loud at least five times, then this movie more or less fits the bill. Obviously there's a law of diminishing returns at work with most sequels - and indeed "threequels", and that's probably the case here. But I was never that much a fan of the first Shrek anyway, to be honest. I mean it was fine, but it wasn't that good. And it's the same here. Don't go in with high expectations, and you'll pass the time reasonably enough. Not exactly a ringing endorsement, but there you go.

How's the maths?
Well, I didn't really see much, which can't be much of a surprise. I guess the title of the movie is worth approving in that at least it doesn't do the silly "Alien cubed" approach. But disappointingly few mentions of differential equations... what is the world coming to?

Can I teach with it?
Well, I daresay a few teachers of other subjects will chuck this in the DVD to keep a class quiet at Christmas. But for maths teachers? Hmm... maybe a little project on the diminishing returns of sequels in terms of quality as mentioned earlier: find a formula for the quality indicator of an "n-quel", where n is a positive integer(*). Is the relationship one of exponential decay? Is it linear? Does Hollywood even care, when the cash register keeps ringing?

(*) Blimey, just realised, what with the business of "prequels", I suppose n could be negative too... and I suppose "Die Hard 4.0" introduces the idea of sequels being rounded to one decimal place. And I've sat through any number of irrational sequels...

I'll get my coat.

Tuesday, July 10, 2007

On holiday

Jings, crivvens and help ma boab, but this blog is almost a year old. There's a thought. Started last year whilst bored during the holidays, and now here we are again. Not that I'm bored. heck no. Just recharging the old batteries, and kicking back. I mean to say, is there a better time of year than the end of July, when hairy Scottish teachers get paid for a month of not working?

By the way, if you are ever bothered by friends complaining about the amount of holidays teachers get, don't bother trying to explain how hard you work at other times/how stressful the job is/etc etc - just say "yes, I know, it's terrible isn't it?" Believe me, it's much more annoying that way.