## Reducing Cognitive Overload in Practicals by graphing with Excel

Confession, they say, is good for the soul. I regret to say that for far too many years as a Science teacher, I was in the habit of simply ‘throwing a practical’ at a class in the belief that it was the best way for students to learn.

However, I now believe that this is not the case. It is another example of the ‘curse of the expert’. As a group, Science teachers are (whether you believe this of yourself and your colleagues or not) a pretty accomplished group of professionals. That is to say, we don’t struggle to use measuring instruments such as measuring cylinders, metre rules (not ‘metre sticks’, please, for the love of all that’s holy), ammeters or voltmeters. Through repeated practice, we have pretty much mastered tasks such as tabulating data, calculating the mean, scaling axes and plotting graphs to the point of automaticity.

But our students have not. The cognitive load of each of the myriad tasks associated with the successful completion of full practical should not be underestimated. For some students, it must seem like we’re asking them to climb Mount Everest while wearing plimsols and completing a cryptic crossword with one arm tied behind their back.

One strategy for managing this cognitive load is Adam Boxer’s excellent Slow Practical method. Another strategy, which can be used in tandem with the Slow Practical method or on its own, is to ‘atomise’ the practical and focus on specific tasks, as Fabio Di Salvo suggests here.

### Simplifying Graphs (KS3 and KS4)

If we want to focus on our students’ graph scaling and plotting skills, it is often better to supply the data they are required to plot. If the focus is interpreting the data, then Excel provides an excellent tool for either: a) providing ready scaled axes; or b) completing the plotting process.

Typical exam board guidance states that computer drawn graphs are acceptable provided they are approximately A4 sized and include a ‘fine grid’ similar to that of standard graph paper (say 2 mm by 2 mm) is used.

Excel has the functionality to produce ‘fine grids’ but this can be a little tricky to access, so I have prepared a generic version here: Simple Graphs workbook link.

Data is entered on the DATA1 tab. (BTW if you wish to access the locked non-green cells, go to Review > Unlock sheet)

The data is automatically plotted on the ‘CHART1 (with plots)’ tab.

Please note that I hardly ever use the automatic trendline drawing functionality of Excel as I think students always need practice at drawing a line of best fit from plotted points.

Alternatively, the teacher can hand out a ‘blank’ graph with scaled axes using the ‘CHART1 (without) plots’ tab.

### Using the Simple Graph workbook with a class

I have used this successfully with classes in a number of ways:

• Plotting the data of a demo ‘live’ and printing out a copy of the completed graph for each student.
• Supplying laptops or tablet so that students can enter their own data ‘live’.
• Posting the workbook on a VLE so that students can process their own data later or for homework.

### Adjusting the Simple Results Graph workbook for different ranges

But what if the data range you wish to enter is vastly different from the generic values I have randomly chosen?

It may look like a disaster, but it can be resolved fairly easily.

Firstly, right click (or ctrl+click on a Mac) on any number on the x-axis. Select ‘Format Axis’ and navigate to the sub-menu that has the ‘Maximum’ and ‘Minimum’ values displayed.

Since my max x data value is 60 I have chosen 70. (BTW clicking on the curved arrow may activate the auto-ranging function.)

I also choose a suitable value of ’10’ for the “Major unit’ which is were the tick marks appear. And I also choose a value of ‘1’ for the minor unit (Generally ‘Major unit’/10 is a good choice)

Next, we right click on any number on the y-axis and select ‘Format Axis’. Going through a similar process for the y-axis yields this:

… which, hopefully, means ‘JOB DONE’

### Plotting More Advanced Graphs at KS4 and KS5

The ‘Results Graph (KS4 and KS5)’ workbook (click on link to access and download) will not only calculate the mean of a set of repeats, but will also calculate absolute uncertainties, percentage uncertainties and plot error bars.

Again, I encourage students to manually draw a line of best fit for the data, and (possibly) calculate a gradient and so on.

### And finally…

Happy graphing, folks đź™‚

## “Squaring The Circle” Or Lukewarm Water? The Disappointed Idealist vs. Horatio Speaks Affair

[They] are like poets, you know, like Shelley or Byron, or people like that. The two totally distinct types of visionaries, itâ€™s like fire and ice, and I feel my role in the band is to be kind of the middle of that, kind of like lukewarm water.

— “Derek Albion Smalls” from This Is Spinal Tap

Chemistrypoet invites someone to “square the circle” between two powerfully written — but diametrically opposed — posts from Disappointed Idealist and Horatio Speaks.

Disappointed Idealist writes that he loathes what he sees as the current government’s obsession with drawing a line in the sand and declaring those on one side winners and the other as losers. He writes movingly of the experiences of his three daughters:

They just called my daughters â€śmediocre failuresâ€ť . . . Like most clever people who donâ€™t have difficulty with language or maths or spatial awareness, or other academic activities, I fundamentally find it impossible to truly understand whyÂ they canâ€™t, despite endless practice, remember how to spell basic words, or how to do basic sums. The school have tried all sorts of different methods of teaching it, and so have we at home, but one day itâ€™s there, and the next itâ€™s gone. Some things stick for a while, some things donâ€™t stick at all . . . At home, they are delightful, loving, awkward, stroppy, generous, always hungry, funny and, above all, happy. But they wonâ€™t â€śpassâ€ť their Y6 SATs.

I am sure most teachers are familiar with that “one day it’s there, the next it’s not” sensation when teaching SEN students (I wrote a post about it a while back). In my experience, patience and kindness and persistence are the order of the day in this scenario (not that anybody says it’s not.) My experience also tells me that sometimes this works, and sometimes it doesn’t.

Horatio Speaks makes the case that recent scientific research shows that all children can be taught to read, write and do mathematics effectively, bar a very few severely disabled individuals.

To which I say: good! Like most teachers, show me a better way to teach and I am all over it. Horatio Speaks goes on to say:

I applaud the passion of the Disappointed Idealist . . . But I would be happier if he â€“ and the thousands who cheered him on â€“ were directing their anger at the education establishmentâ€™s assumption that we will always have children who fail. Itâ€™s a false assumption, as is the emotional caricature that those advocating for more accountability for childrenâ€™s progress care less about the children. I have worked with SEN long enough to know that the most deadly poison is sympathy. It kills by paralysis.

Over the years and from time to time, sadly, I have seen some bad SEN: “death by word search”, for example. And Horatio Speaks is right, bad SEN can kill by paralysis; or, more probably, boredom. But, obviously, not all SEN is bad SEN.

The nub of the disagreement between Horatio Speaks and Disappointed Idealist, I believe, lies in the use of the phrase “children who fail”.

Horatio Speaks rails against an educational establishment that assumes that we will “always have children who fail”. In my view, he is referring to the fact that some children leave school without basic literacy and maths skills.

Disappointed Idealist rails against a system that wants to label children as “mediocre failures”. In my view, he is lamenting the fact that, according to a politically imposed and essentially arbitrary standard, some children will be labeled as “failures” through no fault of their own and that this is, frankly, unhelpful.

My own view is that both of them have valid points. While it is undeniable that some children will do less well than others, by whatever measure is taken, the question is: what should the education system do with this information?

I suspect that both Disappointed Idealist and Horatio Speaks would argue for a diagnostic rather than a judgemental approach as far as each individual student is concerned.

Circle squared? Maybe, maybe not. This is Derek Albion Smalls, signing off.

## Playing the Game

Kings made tombs more splendid than houses of the living and counted old names in the rolls of their descent dearer than the names of sons. Childless lords sat in aged halls musing on heraldry.

— J. R. R. Tolkein, The Two Towers

If there’s anything that makes me lose the will to live, it is being in the same room as an educational Player of Games. I’m sure everyone is reasonably familiar with the type: “I want every intervention from now until the end of term focused on improving the A*-C pass rate for left-handed Y11 students whose birthday month has an R in it.”

Yes, it might help, marginally, in some sense. On such massaging of the margins are modern educational careers and reputations built.

Personally, such considerations leave me cold. Such teachers, it seems to me, hold their statistics in higher esteem than their students. The percentage is adjudged to be the outcome, rather than merely an indicator of a number of successful outcomes.

Sometimes, when I try and express this, people look at me as if I had twelve heads. It is a nuanced and subtle difference of emphasis, admittedly, but I think it’s a valid one. As an analogy, imagine a doctor who focuses on (say) a patient’s temperature to the exclusion of all else: “Doctor, I think I’ve broken my leg.”

“H’mm, let’s have a look. Actually, your temperature is a wee bit high. Here, let me apply this cold compress to your forehead.”

“Well, your body temperature is back to normal now. That means that we now have the officially mandated number of ‘healthy’ patients as per Ofdoc guidelines.”

“But what about my bloody BROKEN LEG?”

“My work here is done. Next patient please!”

The other note of caution that needs to be sounded more loudly in the education world is awareness of what is known as the Halo Effect.

I learned about this in Duncan Watts’ excellent book Everything Is Obvious (When You Know The Right Answer) in which he summaries the work of Phil Rosenzweig:

Firms that are successful are consistently rated as having visionary strategies. strong leadership, and sound execution, while firms that are performing badly are described as suffering from misguided strategy, poor leadership or shoddy execution. But, as Rosenzweig shows, firms that exhibit large swings in performance over time attract equally divergent ratings, even when they have pursued exactly the same strategy, executed in the same way, under the same leadership all along. Remember that Cisco Systems went from being the poster child of the Internet era to a cautionary tale in a matter of a few years . . . Rosenzweig’s conclusion is that in all these cases, the way firms are rated has more to do with whether they are perceived as succeeding than what they are actually doing.

In one early experiment, several teams were asked to analyse the finances of a fictitious firm. Each team was rated on their performance and then asked to evaluate their team in terms of teamwork, communication and motivation. The high scoring teams assessed themselves very highly on these metrics compared with the low scoring teams, as you might expect. However, the kick was that performance scores had been allocated at random — there was no real difference between the teams’ performance at all. The conclusion is that the appearance of superior outcomes produced an illusion of superior functionality.

Watts argues persuasively that we tend to massively underestimate the role of plain, dumb luck in achieving success. He cites the case of Bill Miller, the legendary mutual fund manager who did something no other mutual fund manager has ever achieved: he beat the S&P 500 for fifteen straight years. Watts notes that this seems a classic case of talent trumping luck. However:

. . . right after his record streak ended, Miller’s performance was bad enough to reverse a large chunk of his previous gains, dragging his ten-year average below that of the S&P. So was he a brilliant investor who simply had some bad luck, or was he instead the opposite: a relatively ordinary investor whose ultimately flawed strategy just happened to work for a long time? The problem is that judging from his investing record alone, it’s probably not possible to say. [p.201]

I trust that I do not have to draw too many lines to highlight the relevance of these points to the education world. Outcomes, in the sense of exam grades, are currently the be-all and the end-all of education. But the Halo Effect makes it clear that a simplistic reading of successful outcomes can be highly misleading.

Negating the Halo Effect is difficult, because if one cannot rely on the outcome to evaluate a process then it is no longer clear what to use. The problem, in fact, is not that there is anything wrong with evaluating processes in terms of outcomes — just that it is unreliable to evaluate them in terms of any single outcome. [p.198]

Ofsted. managers and politicians please take note: our search for a signal continues.

Approval of what is approved of
Is as false as a well-kept vow.

— Sir John Betjeman, The Arrest of Oscar Wilde At The Cadogan Hotel