The Longitude Prize 2014

Originally posted on Science Teaching Library:

John Harrison - Longitude Prize 1714 Winner

John Harrison – Longitude Prize 1714 Winner. (Source: Wikipedia)

It’s not every day I write a post for a specific programme to watch for the Science TV and Radio guide, however as I collated the programmes at the weekend I became intrigued by Horizon on Thursday (22th May) evening which was about a reboot of the Longitude Prize.

The Longitude Prize has been interest of mine ever since I read the brilliant book Longitude by Dava Sobel about the prize and the man who won it, John Harrison. The controversy and the fighting over the right to claim the prize are a fascinating tale of the competitive drive that prizes like this can instil. But the huge advances in scientific knowledge and exploration simply because accurate timekeeping at sea was now possible are not to be taken lightly.

Just one example: Captain James Cook, who is another scientific hero of mine, confirmed Edmund…

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Could we crowd source concept maps for what we teach? #ResearchED #Touchpaper

Originally posted on notatextbook:

At ResearchED Birmingham last weekend, Alex Weatherall and I used our presentation to sound out the delegates on an idea that stemmed from our previous discussions on Touchpaper Problem 4: determining the complexity of a concept. Many thanks to everyone who attended and listened to us. Even more thanks to those who have since been in touch with reviews, comments, questions and suggestions.

Physics concept map

I have blogged previously about why a concept map is a useful thing:

  • … it makes you think about the order you do things in as a teacher.
  • … it helps you pitch work at the right level for your students.
  • … you can become more confident in sequencing units of work.
  • … it identifies gaps in your own subject knowledge.
  • … it provides you with a diagnostic for correctly identifying your students’ misconceptions.
  • … it can help you pre-empt difficulties.
  • … it involves identifying threshold…

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Rigorous Dimensional Analysis at the DfE

OK, I’ll warn you now. Some of you may think what follows is pedantry, pure and simple. For that I make no apology (but I do make an apology for spelling Rigorous wrong in the original title of this post – the irony is not lost on me).

Yesterday, the GCSE subject content for Combined Science was published and (as brought to my attention on Twitter by @Alby) on page 35  were the set of physics equations that students were expected to learn off by heart – they included one that I had never seen before:

kinetic energy = 0.5 × mass × (acceleration)2

Now being a trusting chap I thought they must know something I don’t so I thought I’d bring some dimensional analysis to bear on this equation. This is a technique you can use to check that the units (the dimensions) of an equation match on both sides; if they don’t then Huston we have a problem.

So kinetic energy is equivalent to work done  which (as mentioned on the same page) is equal to  force × distance.  Time to bring in the units: newtons for force and metres for distance.

Force as we all know (ahem – see the ResearchEd video coming soon for my own quickly corrected equation boob) equals mass × acceleration. Acceleration has the units metres / second / second or metres / second2   so the units for force can be expressed as kilograms × metres / second2 .

Therefore the kinetic energy which  is usually expressed with the units joules can also be expressed in terms of kilograms × metres / second2 × metres or kilograms × metres2 / second2

So for the equation quoted from the DfE list above is to be a valid equation the units (or dimensions) on the right hand side of the equation have to work out the same; lets see:

0.5 is dimensionless number, so doesn’t contribute any units. Mass gives us kilograms, and accelerationhas the units ( metres / second)2. Combining these gives dimensions of kilograms × metres2 / second4 which is not what we had on the left hand side.

So this equation is clearly not going to pass mustard (yes I know) with my Y10s when I’m teaching the new GCSE curriculum them in 2 years time.

OK so this is an easy mistake to make (well not really – how anyone with any acquaintance with physics typed that equation out is beyond me) but then they did it again.

I’ll not bore you with the maths again, but at the bottom of the page was

(final velocity)2- (initial velocity)2= 2 × acceleration × time

This equation is supposed to be one of the equations of motion that are used to calculate changes in motion during uniform acceleration. However, it is also wrong. It should be:

(final velocity)2- (initial velocity)2= 2 × acceleration × displacement

with both sides having the dimensions metres2 / second2

The DfE have since changed the document (but not before Richard Adams posted this comment in the Guardian ) and republished it in Word format – presumably so they can quickly fix any other mistakes.

They’ve corrected it right, so what’s the problem? They made a couple of mistake in some rather fundamental physics equations and sent them out as guidance. They would have been picked up, undoubtedly, by the exam boards making the changes to specifications if not before.

But their amendments still aren’t correct; they refer to distance in that second equation when it should be displacement, a vector. They refer to speed in the KE equation when really it’s the dot product of velocity which is a vector (the students are supposed to know about the difference between vectors and scalars so why doesn’t their equation list reflect this).

I’ve not even mentioned (though I will now) the other bloopers on that page  such as referring to as the gravity constant when it is the gravitational field strength (nominally 9.81 m/s2 or N/kg) and it is anything but constant (the gravitational constant G is a completely different number 6.67 × 10-11m3 kg-1 s-2).

Using the term charge flow in an equation alongside current is nothing short of confusing but I’m perhaps being a little over zealous here.

And efficiency = output energy transfer / input energy transfer will only ever result in an efficiency of  100% as the energy is conserved – they mean to say the useful output energy transfered 

And  it’s not the first time; last year they mistakenly quoted a definition of Newton’s Second Law as his Third in the KS4 Programmes of Study draft.

And this is just the Physics.

I completely understand that people make mistakes – I make plenty, but these are so obvious that they should have found by proof readers in the DfE or their consultants not by physics teachers on Twitter during their Easter break (almost).

If I was feeling snide I’d mention something about the rigour of the new GCSEs, but I’m not, so I won’t.

I will however repeat my lack of apology for pedantry and I offer my proof reading services to the DfE for when they next release a set of equations.

Here’s the updated document

and Alby’s original tweet:


Edit: Other people who spotted and pointed out errors in this list include @DrDav, @HRogerson and @miss_m_w
Alby has been quoted in this story by Channel 4 News

Artificial Intelligence – is coding like teaching? It depends…


In a former life I was a software developer. I designed algorithms and wrote computer code for a living. I had to learn to use the language that was most appropriate to tell the computer how to do the task I wanted it to do. I had to think like a computer, even when the solution might seem counter-intuitive. I had to be creative, and literal, for the computer does not know what you are trying to make it do. I had to ensure that information was stored correctly in the computer’s memory, and that it could be accessed when needed. I had to be careful to ensure that any problems the computer encountered while processing my code, were handled in the most appropriate way. I had to correctly link to functions that other developers had written to achieve the outcome I wanted from my program.

This morning I posed myself a question:

What makes programming a computer and teaching a child different?

I realise the answer can be simply reduced to the words: many things. I’m really not suggesting that programming a computer and teaching a child are the same, however the paragraph above has so many analogies bursting out of it, that I felt that comparing the two disciplines might be a useful angle to follow as I develop my teaching.

Analogy 1. Code Dependencies

On Saturday 18th January, I attended Laura McInerney’s Touchpaper party at the Institute of Education. Michael Slavinsky led the group discussing problem 4 which asked the question: What determines the complexity of a concept?

Knowing I would be joining this group, my initial thoughts were added to the post above as the following comment:

I think an appropriate way to establish how complex a concept is would be to analyse the network of dependencies the concept has. The more dependencies, the more complex the concept is as it relies on a greater number of previous concepts.

We must be careful not to conflate complexity with complication (i.e difficulty in understanding). They are different things: A student might find a simple concept complicated (difficult) where as his peer finds a more complex concept uncomplicated (easy). I expect how complicated a student finds a complex concept will likely depend on how clear their understanding is of the dependencies.

A dependency in computing helps describe how different parts of a computer program are related and how the different parts of code should be processed by the computer and when. It is important for a programmer to understand the dependencies in order to effectively achieve their goal, but it is also vital for a computer to be able to process these dependencies effectively if it is to carry out the instructions given in an effective and productive way. There is clearly a link to this and the way we teach concepts to children. We scaffold, we build on prior knowledge, we link ideas. So our Touchpaper group concentrated on the idea that it might be possible to define a concept’s complexity in a similar manner. We also explored whether this may also help teachers develop their understanding of the order that topics should be taught (Michael has written about this in his reflection already.)

Here is a very simplistic first draft of the idea that I shared on the day, a basic concept map looking at Newton’s 3 Laws of motion.

Newton's 3 Laws of Motion

Not only are these concepts connected but they are also connected in different ways.

  • Linguistic dependencies – concepts might be described in different ways.
  • Numeric dependencies –  concepts that rely on a mathematical relationship.
  • Intuitive dependencies – concepts that have a link that might be counter-intuitive (or vice-versa blindingly obvious).
  • Multiple theories – concepts that are described by different competing theories, both valid or invalid.
  • Logical dependencies – concepts that require a logical step.
  • Domain dependencies – concepts that are taught in another subject perhaps (e.g.  Biology and P.E.).
  • etc

It seemed plausible to us that these links can be analysed and processed in such a way as for a teacher to be able to arrive at a value that describes how complex the topic is and to be able to use the map to help them plan an effective scheme of learning that will cause the concept to be less complicated for students to learn (and teachers to teach).

We are still working on much of the detail in the group and will have more to share in the coming months. But I wanted to blog the initial thoughts and hope to read some insightful (or indeed inciteful) comments and suggestions.

Other analogies

My intention is to use this idea of the computer coding model to explore other areas of my teaching and I will explore these in future posts including:

  • memory
  • logic
  • scope of variables
  • language of instruction

Transit of Venus

How far away is the sun?

To answer this simple question took a huge amount of cooperation in what was to be the first international scientific collaboration of its kind. Nowadays international scientific projects are commonplace, but in the 18th century it took a rallying call to observe an a rare astronomical event. This event had been predicted to occur in 1761 and again in 1769 and the scientific community was determined to take advantage of this prediction to collect data for a mathematical solution to find the distance to the sun first proposed over 50 years earlier.

Read more of this post

Latest SciTeachJC archive.

We recently discussed curriculum design (using the 5/7E model) in #sciteachjc. Here is the write up by @teachingofsci.

Blog relaunch…

SpaceX Falcon9 & Dragon lifting off last week (22 May 7:44 UTC) (photo: SpaceX / Chris Thompson)

Right, well I’ve just noted the date of my last post at my (aborted) attempt at a blog earlier this year and I am less than impressed with myself. 5 months later and after a lot of prodding from @teachingofsci (who blogs here; he’s been nominated for a blogging award don’t you know) I’ve managed to drag my fingers to the keyboard to crank up the blog again at its new home on WordPress. This sudden call to action is also partly due to the breathing space of a week with no teaching because summer half term starts tomorrow (at 3:05 pm).

I’ve decided that if write down what I intend to write over the next week now, then I will have to get the posts written. So here goes.

Coming soon on TSIAW:

  • Things I’ve Liked. Just like @teachingofsci I have been collecting favourites on Twitter, starring my RSS feeds and building up my bookmarks, and thanks to the excellent suggestion by @cleverfiend I am automatically storing all of these in one place – my Evernote account using the clever event->task service ifttt. So I will review and write about these in small blog posts as regularly as I can (starting with this weekend).
  • Virtual CPD vs School based CPD. I get a great deal of support and professional development from colleagues on Twitter. It truly is an amazing network of people that I have met (online and in real life) during the last 2 years that I have been on twitter. I am going to write a post comparing the CPD I can get in the school setting with virtual CPD (via Twitter and elsewhere) to highlight the advantages and disadvantages of each approach. I will be writing in general terms about the CPD I get in school for professional reasons.
  • My tuppenceworth on the DfE. I have recently been following the many pronouncements of Messrs Gove, Gibb and Wilshaw. I have remarked about the various  statements (and the reporting of these statements) made by the trite trio on twitter a lot recently, and I think I should reflect on some of my views in a more coherent manner (it’s not all negative).
  • Some physics. I really like @alby‘s website He’s a physics teacher that regularly blogs about science that interests him and I have used a couple of his posts as springboards for lessons that I have taught. I also find that I retweet lots of science in the news without saying why I liked it or thought it was interesting (thumbs and phones and 140 character limits can put you off sometimes). So to kick this off I think I’ll write a little post about the transit of Venus due to happen on  5th/6th June. Posted!

Ok, 4 posts in a week. That should keep @teachingofsci quiet.


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