Author Archives: Drew

On Friday 14th August, the SQA announced its Arrangements for National 5, Higher and Advanced Higher courses in the 2020-21 session. This included links to the SQA's Technical Consultation on proposals for modifications to the assessment arrangements for the 2021 exam diet. The announcement also included links to a survey which closed for responses on Monday 24th August. The announcement stated that confirmed modifications would be published in the week beginning 31st August.

I responded to the survey both as a teacher and a parent, but didn't make any copies of my responses, so what follows is from memory.

I was not at all happy with the proposals for the sciences, which amounted to nothing other than a return to the shorter format examination papers of a few years ago. Having lost about a month of teaching time, simply taking 30 minutes out of the exam does nothing at all to help students or teachers. The notion that this reduces work for staff as they will be able to write shorter prelims is laughable. If anything this will create work as prelims will need to be rewritten to match the shortened format.
The failure to recognise that Covid-19 procedures in schools are making practical work exceptionally difficult to conduct, and the lack of a decision to remove the assignment components of science courses does nothing to reduce pressure on students or teachers. Such a decision might have freed up some time to allow courses to be better covered in the reduced time available.

Other options that might have been considered include -
+ reformatting exams to include a mix of mandatory and optional questions, allowing schools to decide which content to leave out in order to compensate for the time lost under lockdown
+ delaying the exam diet until June to allow greater time to complete courses
+ specifying content in courses to be removed to allow the remaining content to be covered effectively

In other subjects proposed changes include removal of coursework components or sections of courses (reduced folio pieces and the removal of the speaking component in English), with no reduction in the examination duration.

Another major concern is about the worth of the consultation exercise at all. With SQA having made it very difficult to understand the related documentation - it is loaded with edu-jargon and emphatically not written for the lay reader - they made it very difficult for students or their parents to respond to the survey.

Whilst many teachers will have responded to the consultation, the limited time available between the release of the proposals on 14th August and the closure of the survey on 24th August will have limited the number and extent of responses.

The plan for SQA to confirm their finalised arrangements during the week beginning 31st August gives little cause to believe that much attention can or will be paid to the survey responses.

I sincerely hope that SQA will do the right thing, listening to teachers, students and parents, and come up with a fair and workable set of modifications.

Thoughts on Assessment (given all that’s been going on)⤴

from Drew @ stuckwithphysics.co.uk

The recent issues surrounding assessment and certification both in Scotland and around the UK, have prompted a great deal of discussion.
With a recent increase in traffic to this blog, mainly to my previous posts on assessment, following a piece I had published in the Times Educational Supplement, I thought it'd be worth putting together an alternative model for assessment and certification.

I should stress that these ideas are not solely my own, they come from discussions with many of the great teachers I count myself lucky to know through Twitter, TeachMeet and Pedagoo, from visits to Canada and the USA, where I heard about systems very different to those here and from an overwhelming sense that what we are currently doing to assess and certificate the learners in our schools isn't good enough.

I'm not suggesting that we get rid of exams. They clearly have their place, but it shouldn't be the only method by which learners in our schools can demonstrate their skills and knowledge. Nor am I suggesting that everything should be internally assessed, this too has its flaws, not the least of which is workload for already time-poor teachers.

My suggested system has four main components -

1. All units at all levels should be assessed online via an eAssessment platform provided by SQA (this already exists in the form of SQA Solar). Unit assessments should be Pass/Fail, with each unit gaining SCQF points at the appropriate level. Students should attempt units when they are ready, and multiple attempts available to students to show they have achieved minimum level of competence (this could be time locked to prevent immediate retest, like the DVLA Driving theory test). This arrangement would need reliable ICT in schools, but if all schools are currently able to undertake the SNSA, then there is already existing capacity which can be built upon.

2. Coursework components should be elective and gain students additional SCQF points. This would avoid the significant burden of multiple assignments for students following more than one in science or social subjects course, allowing a single exemplification of generic skills within a subject area.

3. All terminal exams at all levels (including N4 if there is sufficient demand) should be elective, allowing students to gain additional SCQF points. This would allow flexible routes for students to bypass exams if not required for their chosen path. Students who require Higher passes, i.e. for university entry, are still able to meet these requirements.

4. All learners accumulate 'learner credits' via a unique online profile, which could be integrated into, or linked to their Glow account. This would allow all of a learner's achievements, not just SQA, but Prince's Trust Achieve, John Muir Award, Duke of Edinburgh Award, Saltire Award and any of a range of other awarding bodies included in the SCQF framework, to be recorded. Each achievement could be electronically 'tagged' with metadata to detail the knowledge, skills and experiences underlying the award (using Mozilla Open Badges or similar). These could be cross referenced with searchable index of skills & awards which could be used by employers, FE colleges and Universities to assist in candidate selection.

I don't pretend that my proposed model is perfect, I know it would take a great deal of investment, both in financial terms and in terms of time, to develop and bring about such a set of changes.

What I do know is that, given all that's been going on, we are long overdue for a serious discussion about how we assess and certificate our learners. Such a discussion cannot be left to those in the walled gardens of the SQA, Education Scotland and the Scottish Government - they're most of the reason that things are so greatly in need of reform.

Thoughts on SQA Exams & Certification⤴

from Drew @ stuckwithphysics.co.uk

In response to a discussion about assessment on the IOP Sputnik email forum for Scottish Physics teachers, I posted some thoughts on what the SQA could do differently. Some replies to the post suggested I should share these ideas further.

It's a bit 'sassy' in places, as one of the replies put it, but here's the post, sass and all -

Alasdair replied to an earlier post saying ' If only the SQA had a big bank of questions in single page word format, say 20 for each key area, and some kind of random test generator software. '

At the risk of this opening a can of worms and with apologies to anyone who has ever had this discussion with me in the past...

If the SQA had a bank of questions they could relatively easily use it to automatically generate unique assessments that candidates could complete entirely electronically, that could be marked, totalled and graded automatically, either as individual key areas/units or as a full course assessment. Any such system could probably automatically certificate the candidate at the appropriate level, and award tariff points too. And if such a system were live all year round, candidates could learn at their own pace, within reasonable bounds, and choose the date and time that they took the assessment. Dare I say it, a bit like a driving theory test...

Such a system might also allow candidates a number of attempts at an assessment, until they achieve a pass (perhaps with a period of time between to consolidate and revise), rather than writing them off after two attempts. A bit like a... oh, you're there already...

For those candidates who *need* an exam grade for Uni entry (they could just do their own entry exams), or those so ingrained in the 'exams are the only thing of any importance' culture that pervades all discussions of education, there is no reason why terminal exams could be not be continued - perhaps with those candidates gaining extra tariff points for the additional attainment. A bit like a driving licence awarded after a practical test...

Granted, schools would need to verify the identities of the candidates attempting assessments (so their big cousin isn't doing it), have a dedicated suite of PCs on which these assessments could be done where online access is limited to only the assessment site, and have a reliable internet connection with sufficient bandwidth. A bit like those places where you do your ..., oh, and again...

These arrangements would require a significant investment, but might go some way to allowing all candidates to achieve at a level that is appropriate to their abilities. There's every chance they could contribute to reducing the attainment gap (if not the poverty that causes most of it) and no doubt whatsoever that they would significantly reduce teacher workload.

If only the SQA had such a bank of questions...

And if they do, then why aren't we doing things better by our kids and for ourselves?

Comments, as ever, are very welcome.

Perimeter Institute – EinsteinPlus 2016 – Day 3⤴

from Drew @ stuckwithphysics.co.uk

Day three began (after breakfast) with a session on Quantum Mechanics. The session was based around the 'Investigating the Nature of the Electron' activity from the Perimeter Institute's materials on 'The Challenge of Quantum Reality'.

The first task, 'Classical Particle Behaviour', uses very simple apparatus - sand and a paper coffee cup, to model the behaviour of particles passing through two narrow slits - Young's slits experiment. The task asks students to make a prediction of what they will see, encouraging them to explain their reasoning before continuing with the procedure of passing a small amount of sand through two narrow slits cut into the base of the cup.

As expected, two small piles of sand are obtained,

Perimeter Institute – EinsteinPlus 2016 – Day 3⤴

from Drew @ stuckwithphysics.co.uk

As expected, two small piles of sand are obtained,

Perimeter Institute – EinsteinPlus 2016 – Day 2⤴

from Drew @ stuckwithphysics.co.uk

Day 2 of EinsteinPlus 2016 saw the group formally welcomed to the spectacular Perimeter Institute building after an equally spectacular breakfast. (There are two excellent bistros at PI, which provided the group with a fabulous range of meals over the week long visit. I'd say more, but there'd be a real danger of this becoming a food blog...)

The morning session was split into two -

Cosmology - this used an existing PI activity 'The Signature of the Stars' from their educational resource on 'The Expanding Universe' - using diffraction glasses observations were made of line spectra from a variety of gas discharge lamps. These spectra are used to identify the elements present in stars, in the Milky way and in distant galaxies. The spectra of light from distant galaxies shows the same spectral lines as stars in our galaxy, but the lines appear in slightly different positions, with longer wavelengths. This effect, known as Red Shift, occurs because the galaxies are moving away from us, and each other, at high speeds. Measuring the red shift for a galaxy can be used to measure its speed, which relates in turn to its distance from us. This effect was first observed in the early 20th century and used to formulate Hubble's Law - which states that not only is the universe expanding, but the further away from us a galaxy is, the faster it is moving. The activity includes data allowing the red shift of a range of galaxies at different known distances to be used to find their speeds. This data is then plotted it give a graph representing Hubble's Law, which gives an approximation of the Hubble constant and can in turn be used to find the age of the universe.

Gravitational waves - this used a newly developed activity based around the recent detection of Gravitational Waves at the Laser Interferometer Gravitational Wave Observatory (LIGO) facilities in the USA. The facilities use extremely large scale (~4km) laser interferometers to measure incredibly small expansions or contractions (~10^-19 m - 1000 times smaller than the diameter of a proton) of the devices which occur when gravitational waves pass. There are many areas of physics and engineering involved in the development and operation of the LIGO detectors, from the solutions to Einstein's General Relativity which predicted the existence of Gravitational waves, to the intricate suspension of the mirrors sued to improve the sensitivity of the detectors - developed at the University of Glasgow. The activity centres around the properties of waves, and their behaviour when they undergo reflection - beginning with demonstrations of mechanical waves using a slinky. Observations of phase change upon reflection were developed upon and related to the operation of the interferometers at LIGO. These ideas were utilised in a hands on activity to simulate the paths of the laser light used at LIGO in order to find the nature of the light detected when the device is unstretched (no gravitational wave) and stretched. This task offers an excellent opportunity to link this part of the Advanced Higher physics unit on waves to a context which involves real, cutting edge physics.

After lunch, followed a two more sessions -

Neutrino Detection - another new activity, this is based on the Nobel Prize winning work of Professor Art McDonald and his team at the Sudbury Neutrino Observatory (SNOLAB). The session began with an overview of the production of neutrinos in the sun and the difficulty in detecting these particles - the 'Solar Neutrino Problem'. The session continued with a description of the facility at SNOLAB and a hands on task modelling the detector using marbles, cardboard boxes and a baking tray. There was a great deal of discussion about this task, and the nature of the model to describe and explain neutrino detection. Consequently there was a shortage of time for the remaining tasks, dealing with real data from SNOLAB and the theory of 'neutrino oscillation'.

Dark Matter - this session used the 'Dark Matter Within a Galaxy' activity from 'The Mystery of Dark Matter' materials. The activity begins with a revision of the basic rules for circular motion and gravitation, using a range of data to find and plot the orbital speed of a star against its radius from the centre of its galaxy. These values, calculated from classical theory, do not compare well with observational data - implying that there must be more mass in these systems that we can not detect - Dark Matter. Whilst the part of the underlying physics of this task, circular motion, is beyond the scope of the Higher physics course in Scotland, it might be fair to use this as a practice data handling task which could be used to exemplify and reinforce the very brief mention of Dark Matter in the 'Our Dynamic Universe' unit.

The final session of the day was a keynote presentation delivered by Professor Avery Broderick from the University of Waterloo on the Event Horizon Telescope (EHT). This program uses nine existing telescopes across the globe and applies a technique known as Very Long Baseline Interferometery (VBLI) to improve the resolution at which images of very small objects can be made.

It is hoped that by improving the resolution for existing telescopes and including planned future telescopes in the gathering and processing of data, the EHT will obtain the first direct images of the event horizon for a black hole in our galaxy. Recent observations in the constellation of Sagittarius are thought to indicate the presence of a black hole with a mass around 4 millions time that of our sun. This black hole is of the right size and at the right distance for the EHT to be able to make observations that will allow an image to be obtained in the next few years.

The data gathered and images obtained by the EHT will allow for further testing of Einstein's theory of General Relativity, and provide a greater understanding of phenomena such as black hole accretion and plasma jets.

After this presentation and another excellent meal the group was offered a tour of the Perimeter Institute building, offering an insight into how the facilities have been designed and developed in order to attract and facilitate the work of some of the world's foremost theoretical physics (not to mention a very large number of teachers and students).

A selection of images of the building will be included in a gallery as soon as I figure out how to make it work...

Perimeter Institute – EinsteinPlus 2016 – Day 1⤴

from Drew @ stuckwithphysics.co.uk

Earlier in the year I was delighted to receive an invitation to the annual Einstein Plus teachers' summer school at the Perimeter Institute in Waterloo, Ontario.

A total of forty two teachers from across Canada, USA, Europe and Asia attended the event, comprising workshops, lectures and visits from the 6th to the 12th of July.

Having registered and settled into our accommodation for the week, the first evening was given over to a delicious meal followed by a session of group 'ice breaker' tasks at the Hawk's Nest, Wilfrid Laurier University - one of two universities in the city of Waterloo.

One of the tasks was on the 'Process of Science' and involved the use of some small wooden cubes. Each of five of the faces carried a name and two numbers as shown in the images below.

Groups were asked to make observations, try to identify relationships and then predict what could appear on the blank face of the cube. Each group was able to complete all of these steps, but interestingly no two groups came up with exactly the same solution. All of the suggestions given were equally valid, given the evidence on which they had been based. This task made an excellent introduction to the idea of scientific modelling, a theme which would be returned to throughout the week.

Newton’s G-ball⤴

from Drew @ stuckwithphysics.co.uk

'Newton's G-ball', marketed by Swedish company Mollic, is a simple electronic timing device which can be used to measure the freefall time from its point of release to impact on a surface below.

It is available from a number of third party suppliers, including djb microtech, Better Equipped and TIMSTAR in the UK and Arbor Scientific in the US.

The ball has an integral centisecond timer, which is primed by pressing and holding the button on the face of the timer. Releasing the ball starts the timer, which stops when the ball impacts upon a surface below.

If the height, h, through which the ball falls is known, and the time for the ball to fall, t, is measured, then g can be calculated using the formula -

Taking multiple measurements of the freefall time, t, over a range of heights, h, allows a range of values to be obtained for g.

The results below were obtained by my Higher Physics class on 9th June 2016.

h (m)	t₁	t₂	t₃	mean t (s)	g (ms^-2)
0.2	0.23	0.22	0.27	0.240	6.94
0.4	0.30	0.27	0.30	0.290	9.51
0.6	0.39	0.35	0.38	0.373	8.61
0.8	0.42	0.39	0.41	0.407	9.67
1.0	0.46	0.48	0.46	0.467	9.18

The results obtained are reasonably good, giving a mean value for g = 8.79 ms^-2. Whilst this is in reasonably close agreement with the quoted value of 9.8 ms^-2 given in the SQA data tables, discounting the obviously low value obtained for h = 0.2 m gives an improved mean value for g = 9.51 ms^-2.

A quick analysis of the uncertainties in this data give the following -

Uncertainties in height, h (approximate reading/position uncertainty = ± 0.02 m)

h (m)	uncertainty in h (m)	% uncertainty in h
0.2	0.02	10%
0.4	0.02	5%
0.6	0.02	3%
0.8	0.02	3%
1.0	0.02	2%

Uncertainties in time, t -

h (m)	t₁	t₂	t₃	mean t (s)	random uncertainty in t (s)	% uncertainty in t
0.2	0.23	0.22	0.27	0.240	0.017	7%
0.4	0.30	0.27	0.30	0.290	0.010	3%
0.6	0.39	0.35	0.38	0.373	0.013	4%
0.8	0.42	0.39	0.41	0.407	0.010	2%
1.0	0.46	0.48	0.46	0.467	0.007	1%

Uncertainties in g -

g (ms^-2)	mean g (ms^-2)	random uncertainty in g (ms^-2)
6.94	8.79	0.55
9.51
8.61	% uncertainty in g	absolute uncertainty in g (ms^-2)
9.67	8%	0.70
9.18

This gives a final value for g using this procedure as -

g = (8.79 ± 0.70) ms^-2

However, an alternative graphical analysis allows an improved result to be obtained from the same data.

For this approach, the formula above was rearranged for h, giving -

A graph was plotted of h against t², giving a good approximation of a straight line through the origin, as expected.

t² (s²)	h (m)
0.0576	0.2
0.0841	0.4
0.1394	0.6
0.1654	0.8
0.2178	1.0

Using the trendline function in Excel, a best fit line was added with its function included. The gradient of this straight line, which is equal to ½ g, is 4.91, giving a value for g from this graph - g = 9.82 ms^-2.

Further analysis of the graph, using the LINEST function in excel, gave the following uncertainties -

gradient	uncertainty in gradient	% uncertainty in gradient
4.91	0.33	7%

g (ms^-2)	absolute uncertainty in g (ms^-2)
9.82	0.69

This graphical treatment of the data gives a final value for g using this procedure as -

g = (9.82 ± 0.69) ms^-2

I have included the raw data, graphical treatment and uncertainties in the in the excel file below.

g ball

Model Linear Accelerator⤴

from Drew @ stuckwithphysics.co.uk

Last June, I made a model particle accelerator using a plastic salad bowl. This was courtesy of a great 'cook-along' online CPD via Google Hangouts hosted by a fellow IOP Network Coordinator, Dan Cottle (@blendedlearner). Dan's video can be seen here - https://www.youtube.com/watch?v=4yU7rzgrg6A

This tweet from @ArdAcadPhysics shows the accelerator in action -

First there was the Salad Bowl Accelerator @PhysicsDrew #higher #particles... pic.twitter.com/JQJyj1nBES

— ArdAcad Physics (@ArdAcadPhysics) March 21, 2016

After building my own I was left with a huge surplus of aluminium tape, graphite paint and polystyrene balls, so i decided to run some CPD sessions to build it with other physics teachers at my own IOP CPD events.

The last of these sessions was at the ASE Scotland Conference in Aberdeen at the beginning of March. At my session one of the attendees asked it it would be possible to make a linear accelerator along the same lines. At the time the thought hadn't occurred to me, but I had a bit of a think about it over the following weeks until I found a bit of time (and the need to try it out with my own Higher physics class).

Using a bit of guttering my technician had in the stores and a lot of my surplus aluminium tape (I still have half a roll), my colleague Kenny Bell (@ArdAcadPhysics), through a process of trial and error managed to put together a working model of a linear accelerator.

Like the salad bowl accelerator this uses alternate strips of aluminium tape connected to a Van De Graaf generator, one side to the negative dome, the other side to the earth terminal.

A thin strip of aluminium tape was run along each edge of the guttering to provide common 'rail' connections form each of the terminals on the Van de Graaf. The dome is connected to the side furthest from the camera in the image above. This inturn connects to the end from which the polystyrene balls start their acceleration, which is capped and has aluminium tape over the end cap and the base of the gutter. (Care was taken to avoid having the tape touch the earth rail, which would cause a short circuit.)

IMAG0846

Alternate strips of aluminium tape were connected to each of the edge rails to give alternately negatively charged (connected to the dome) and neutral (earth) electrodes. Initially electrodes of different widths were tried, but this arrangement was unsuccessful.

With the connections made, a polystyrene ball coated in conductive graphite paint was introduced at the capped end of the accelerator and the Van de Graaf generator was switched on.

By trial and error @ArdAcadPhysics and I made a guttering linear accelerator. #asechat #physics pic.twitter.com/eNfF2noLmS

— Drew Burrett (@PhysicsDrew) March 21, 2016

A bit of tinkering was required to get the ball to accelerate along the warped guttering - achieved mainly by clamping it down to the desk. Further tinkering allowed it to be used to compare the acceleration of larger polystyrene ball with the smaller ones.

More discussion lead to the idea of using the linear accelerator to inject particles into the circular accelerator. Again, Kenny Bell offered invaluable assistance in achieving this.

Linear accelerator injected into circular accelerator #particles #higher @PhysicsDrew pic.twitter.com/qv3PvzfhyY

— ArdAcad Physics (@ArdAcadPhysics) March 24, 2016

If you want to use my example as a start point to build your own, please feel free to do so. if you have any questions, please get in touch via the comments below, or tweet @PhysicsDrew.