Tag Archives: Modelling

Public Mathematics in a Pandemic

Not so long ago I had a very minor Twitter spat with a former student of mine in which I advanced the view that knowing the Fibonnaci sequence was more useful than instant recall of 11×12. I was shot down, with the suggestion that I didn’t care about working class kids. Well, I guess, I would like to claim that I care about all kids, regardless. And, it seems that being able to read and understand mathematical information has suddenly become a whole lot more important than previously. Oddly enough, memorising specific number combinations has not proved to be of any great importance in this. Nor, to be fair has the Fibonnaci sequence cropped up. But, of course making sense of patterns and relationships absolutely has. We now live in a world in which it is expected that we can look at a graph with a logarithmic scale and read it sensibly. Also, we are being told (as I write) that the rate of increase in case numbers is decreasing. From this we need to know if the case numbers are going up or down and thus, what is in fact decreasing.

In school mathematics, the myth of application is ever present. Mathematics solves problems in the real world we are told. Except that we start from a curriculum containing specified mathematics, that must be taught, generally in a given order. So, of course, the real world is bent and twisted to fit the mathematics that needs to be learned. In our teaching of distance and time, how often does a car travel at a uniform speed, showing a straight line on a distance time graph starting at the origin? (Instantaneous acceleration is a useful phenomenon in maths lessons, but nowhere else). The pandemic has not thrown up many linear models, or even quadratic models. Learning the maths presented in a distorted and damaged context is worse than unhelpful. Either the learner knows enough about how the real world works to recognise that the maths lesson version is simply not real and therefore the maths is not a model of it, or worse they build their knowledge of the world through this damaged notion that cars really do travel with contant speed, starting from rest. So, when stuff actually matters, as it really does in this pandemic,  learners of school mathematics do not have the tools (they were not allowed to play with functions, instead they had to learn linear, then quadratic and never quite reached exponential) and would therefore expect reality to be required to fit. So, the growth rate graphs with the exponential scales, that then look much more linear, show the death rates in the USA only ever so slightly higher than those in Germany. This can only be because that is the way it was.

If we are to claim that maths has some use value and relavence to the word outside the maths classroom (as this year it really has like never before), then we need to engage our students in sense making. Looking at live data and playing with the maths to see how and where it might fit. With graphing software it is no harder to draw an exponential than a linear function and when it is driven by data that the learner has some investment in, then they will want to know. Building relationships between a felt and experienced world and mathematical objects useful for representing it, is complicated and muti faceted, but possible if we allow the setting to lead the maths rather than the other way round. I still have some ultrasound distance sensors which we would use connected to real time graph drawing software. Students would walk on a straight line towards and away from the sensor to create different distance time (and later velocity/time) graphs. In this way the relationship is created and really felt. The motion to create a sine curve as a distance/time graph is a very lovely thing. Equally our Pizza project had students find models for the cooling of a pizza from short term data (it looks very linear over the course of a 10 minute experiment, but what does that say about what will happen in the medium to longer term?) The implications of a model can only be engaged with in a context which behaves as the real world actually does.

I picked the Fibonnaci sequence as an example of interesting variation. 11×12 is not interesting, nor is it useful (except, I did find this example). To make sense of a world that behaves as the one our students actual live in does, they need to see what they learn as a examples from a range of useful tools that can, when critically applied, give us ways of seeing what happens in that world in a more manageable way. Linear and quadratic are examples of functions, of which there are many, many more. Times tables are number relationships of some power and Fibonannaci, Square, Triangle numbers also. So, when we see variation and relationship we take a flexible, open and always critical view of it.

The Mastery of Multiple Representation

I was invited speak at the Maths Mastery conference in London last month. My essential brief was to engage with using technology to support mathematics learners. I have increasingly wanted to take a wide view of things so I interpreted technology very liberally. Having trained teachers in using graphing calculators for both TI and HP for many years, I am well versed in the language of multiple representations. The possibility is there to see a function represented graphically, symbolically and as a table of values and to swap quickly between them and to see how each representation gave you different insights into the nature of the function.

For example, a linear function has a particular algebraic form, it has a straight line graph and a table of values with a common difference. We exploited all of these in our Pizza project, showing that the natural tendency when watching change over time (the declining temperature of a cooling pizza) is to look for a linear change. The difference is roughly equal over the minute intervals we used, for the 10 minute length of the experiment. This is forcefully confirmed visually when a real time graph being drawn is very nearly a straight line. So, we feel empowered to hypthesise a linear function which symbolically can be used to calculate extrapolations. It is these that undermine our initial thoughts (put time = 24 hours into the function and we quickly see there is something wrong). Then we can go back to the graph and change the axes to see the nature of the slight curve and look again at the nature of the differences from equal differences, which themselves have a pattern.

Continue reading The Mastery of Multiple Representation

The New National Curriulum

Well, mathematical modelling now has a serious place in key stage 4. So, get yourselves ready. Do not look through the document looking for any coherence, though. You won’t find it. This is another pot-pouri. Some very odd things like frequent reference to mechanics as an example of mathematical modeling, even though it is not taught as that at A level. More a collection of known models being applied. The real trick is to get students to develop their own models critically and develop methods for validation. That’s why real engineering projects go through more than one development iteration and A level mechanics problems do not. My Pizza Project article develops the model creating phase here. Also, Venn diagrams are back for probability problems, but set theory is not. Vectors in different format are back, but matrices are not. My favourite is the explicit teaching of Roman numerals (up to 100 in year 4 and then, I kid you not, up to 1000 in year 5).

Mr Gove was on question time yesterday. We cannot learn to be creative until we have a through grounding in the facts and techniques needed, he says. Everyone agrees with this (including our good selves). The trouble is, that no-one questions which facts and techniques and for why. The secretary of state himself quotes long division as an example. But could he tell us which creative mathematics is opened up by being able to do long division. Certainly, at A level we can divide polynomials this way, and for sure, unpicking the process to see how it works, provides deep insights into the power of place value, but, as a technique to be learned, it is just a pandering to an imagined perfect past. The trouble for us, is that everyone … the man from industry, the children’s author and all of the politicians agree with him. I say get kids to memorise Pascal’s/The Chinese triangle and chant their squares, and cubes. That would genuinely help them engage with maths creatively. But 11×12? Why? Is old money making a comeback?

So, there’s a big opportunity. Some interesting if oddly chosen hard maths, that modelling word and even ‘proof’ is in there too. An absence of levels is a major blessing. But, ordinary kids have to be able to do this. Escalante got all of his students to AP calculus with ganas. We must be able to do this too. The stakes have been raised.

Cape Town Maths

Two weeks ago, I had a very nice trip down to Cape Town. It is a very beautiful city indeed. However, I did a series of sessions mixing HP Graphing Calculators, GeoGebra and Data Streaming to groups of maths teachers, trainee maths teachers and undergraduate engineering students at the Cape Penninsula Technical University and the University of the Western Cape. South Africa, in the post apartheid era has been trying to bring all of its education systems up to the level of the former elite schools. As you can imagine, this is a tough task, although the government’s commitment is clear having one of the highest proportional spends on education anywhere in the world. The universities I visited are excellent examples of that move to change and I was delighted to work with really enthusiastic students and teachers. Continue reading Cape Town Maths

Brunel AND Nelson in King’s

The ATM/MA london Branch was treated to on of Peter Ransom’s barnstorming performaces last Saturday. A big message that we share with our PGCE students is that teaching is a performance art and ensuring that your lessons have a good dose of theatre will bring students in to your message. Well, Peter brings avery big dose of theatre. Right down to the brilliant stand-up touches … is he really going to drop the cannon ball? Well, yes, naturally. We got through transformational geometry, force functions in suspension bridge chains, cannon ball stacking sequences and the destructive impact of cannon balls by linear and quadratic scaling. So, no messing maths. Please come back soon to see the photos … and come to our next session which will be 10:30 Saturday 24th March (King’s College London, the Franklin Wilkins Building on Stamford Street, SE1, just down from the IMAX cinema), which is the Danny Brown maths Workshops. Read all about it at Danny’s site: www.makemaths.com

HP STEM Activity Competition

To any teachers out there who come across my blog, we have a competition:

WIN 30 HP40GS calculators and a data streaming kit (worth £2000)

We are setting up an exemplar STEM teaching room for teachers. We need top quality activities to do in the room, which will be premiered at the Olympia BETT show. We need a detailed exposition of the activity together with any supporting materials (e.g. worksheets etc.) In entering, you give us permission to use the activity (suitably credited) in the STEM room and in a booklet which we will produce with all of the entries and which will be available free to teachers. We would like activities using HP39/40GS or 50G graphing calculators, but any other software which runs under windows (and therefore on the new HP windows 7 slate) would do fine. The activity must be an application which merges mathematics with science or engineering. Send one zipped folder of files with your full contact details to: chris.olley@kcl.ac.uk. Closing date is Friday 9th of December.

Applied Maths

So, why do we teach students maths in school? How tempting it is, to say “because it’s useful”. Well, I defy anyone to respond to this post by finding a single example taking from a school maths text book, in which something happens that (a) could be described as useful and (b) happens in the manner that it might do if someone were actually doing it. Continue reading Applied Maths