What is “Heath”? The importance of representation.

“What is Heath, Sir? That question really threw us”

They were referring to this question, from an Edexcel past paper:

Past paper question that begins "Heath is researching..."
Past paper question that begins “Heath is researching…”

I hadn’t expected that challenge. I realised that not one of the class in front of me would have met a “Heath”. I later looked at all the names used in the past paper questions I had been setting: William, Julie, Kerry, Xander, Hamish, Fiona, Kirstie, Byron, Grahame, Marian, Victoria, Johnny (there’s always a Johnny).


I looked at the register: Yahya, Bilal, Naziba, Tahira, Adedeji, Mohamed, Manas, Caoimhe, Abdullah, Chandan, James, Sufyan, Nathan, Harry, Jamiha, Aseel, Isla, Zoya*

I had a think about this. I read some stuff on the importance of representation and cultural relevance. And I changed my mocks and test papers to include names from all the cultures of the children in front of me. It’s a small step but the right thing to do.

More importantly perhaps the exam boards have started doing the same. OCR’s recent (since 2020) papers have included the names Hope, Daniel and Rob but also Ali, Naomi, Iqbal and Amir.

That’s why I was a little frustrated to read a post on Facebook a few months ago that read “I’ve made this exam paper, with all the ‘politically correct’ names changed to Star Wars characters!” I wonder if that teacher had an Ali or a Naomi in his class, and what joy they might have been denied, not seeing their own name (or a name popular in their culture) in the materials in front of them.

It’s fine to try to add a little fun to proceedings and jump on the kids’ current interests, but please don’t do it at the expense of representation. Also I appreciate this might seem trivial, but every little counts as we try to make our curriculum more inclusive.

* this is a fictional register using students first names I have once taught, not a current register of any class, but it is representative of a typical class in my school.


“Love Computing 2022”, free CPD 10-14 Feb.

Update – scroll down for the slides I presented at these sessions. If you enjoy this content why not buy me a coffee?

I was delighted to present a couple of sessions at this event alongside a wealth of talent, including…

Brochure cover showing vintage picture of woman looking at computer with heart graphics over eyes
Love Computing brochure front cover
  • Marc White, Ofsted National Computing Lead
  • Sue Sentance, Raspberry Pi Foundation
  • Dr Carolina Kuepper-Tetzel, The Learning Scientists
  • William Lau
  • Isaac Computing
  • Raspberry Pi
  • CAS
  • BT
  • Ellie Narewska, Guardian
  • Code Club
  • STEM Ambassadors
  • Quafaro, Cyber security
  • The Centre for Computing History
  • The National Centre for Computing Education plus lots more

See the brochure here, and book here. My two sessions are as follows (scroll past the ad which helps me maintain this blog!):

  • Computing Pedagogy: Hinterland, Misconceptions and Semantic Waves – powerful tools for progress. How reading around the subject can improve your delivery, how “Semantic Waves” improve student understanding, and how misconception-aware teaching gets great results. I explore these pedagogical tools with a focus on how they can be used to great effect in GCSE Computer Science teaching. – Slides now available here and recording below:
  • Networks and System Security for GCSE success. A detailed look at the GCSE Networks and System Security specification and how to teach it. Demystifying client-server and P2P models, network protocols, security threats and countermeasures, helping you confidently teach these topics. – Slides now available here and recording below.

Enjoy, and remember to tip me a couple of quid for a Cappucino with an extra shot… 🙂


What pub quizzes taught me about MCQs

Consider these three questions:

a. What is the highest mountain in Africa?
b. Kilimanjaro is the highest mountain in which continent?
c. Where is the only place in Africa can you find snow all year round?

I enjoyed pub quizzes in my 20s. I used to do three a week, but some were more enjoyable than others, and this was usually down to the quality of the questions. Anyone can take a fact like “Kilimanjaro is the highest mountain in Africa” and turn it into question a, above. But there’s no fun in that question for the participants. You know it or you don’t.


Example b at least opens the question to everyone on the team, we’ve all heard of continents, right? And we can use what we know about language to have a stab at the origin of the name. It’s an “all-play” question.

Example quiz question
Example quiz question

Example c however is more fun. Now we have to think laterally: where can we find snow in Africa? Is it cold at the extreme north or south? Is there an island in the Southern Ocean that counts as part of Africa? Oh wait, high altitude. And so we have a fun team discussion about geography, and possibly some debate before arriving at an answer, and hopefully the obligatory “told you so” when the answer is revealed. Pub quiz gold.

Why is (c) more fun? We enjoy low-stakes quizzes. As humans we like to test ourselves, and when there is nothing to be gained except maybe a voucher for a round of drinks, then there’s no pressure. But questions like (a) are dull, they don’t test anything except facts. If you don’t know, you can’t guess. The other two allow us to take part and make an educated guess. They also get us thinking quite hard.


This act of “thinking hard” is exactly what we want to generate in the classroom, see Adam Boxer’s blog on ratio for more on this. Low stakes quizzes are a good way of doing that, and many schools now incorporate daily and weekly recap quizzes at the start of lesson. But there are good questions and bad questions. A question should be sufficiently challenging that it causes meaningful thought (Bjork’s desirable difficulty) but achieveable for most students (Rosenshine’s high success rate).

Before I was a teacher, I was enjoying pub quizzes and occasionally creating them for my friends and family, and discovered these principles through trial and error. (It still irks me when a friend writes a quiz full of type “a” questions, but I bite my tongue). Now we have the research to back up why type “c” questions (my characterisation only) are more enjoyable and more valuable.


If you want to see what I did with all of this research, I wrote the verified GCSE Computer Science content for Quizlet, including 800 multiple choice questions, available for free here. Use these in your classroom. And stop asking “Kurt Cobain was the lead singer of which band?” and start asking “Which seminal Seattle rock band, whose singer tragically died by suicide in 1994, shares its name with the ultimate goal of Buddhist meditation?”


Alexa didn’t tell a child to electrocute herself, and why it’s important.

You can’t have missed this story:

Image from BBC News page for Alexa "coin challenge" story
BBC News page for Alexa “coin challenge” story

I’ve read this story on several websites now and become enraged at the lack of technology insight provided. Why? Because how we discuss technology and its impact on our world matters. It really does. Tech is changing the world in ways we are yet to understand, so we really need to explain it well in news stories like this, and in the classroom.


So let me start with the headline of this blog. Alexa did not “tell a child to touch a live plug with a penny”. Alexa outsourced the query to an internet search, having found no adequate response in its database. The girl will have heard the following: “Here’s something I found online…” before Alexa proceeded to read a web page published by someone else, not Amazon.

In this way, the girl has basically performed an internet search. Nothing more, nothing less. The girl and her family, and the journalists who love a good “tech gone bad” story, lapped it up and reported it as a “fault with Alexa”. Amazon was quick to claim it had “quickly fixed an error”, which just means it changed the heuristic for web pages that mention the coin challenge, so they will no longer be selected as an appropriate response.

There are two issues with this reporting… (scroll down for more…)

  1. The only popular web pages about the “penny challenge” or “outlet challenge” are those warning parents about the challenge, such as this one from CBS News. Like the “Tide pod craze” of 2018, this is largely an attempt by teens to freak out other teens and adults, the actual numbers of children and young people putting themselves at risk is probably vanishingly small, which is why as adults we must be careful we do not amplify the risks by unnecessary overreaction, which causes more children to take risks, through the Streisand effect.
  2. Blaming Alexa here is shooting the messenger. Alexa simply relayed the content of a popular web page, but because we have learned to trust algorithms to make better decisions than humans in so many aspects of our lives (which is a big issue, too big for this column), we are more likely to take advice from an AI such as Alexa than a static webpage we found ourselves (or at least we believe we found ourselves!). Alexa also divorced the content from its context, which was almost certainly the CBS webpage or one similar that gave a warning of the dangers of the “challenge”.

I gave a talk at a recent CAS meeting about the dangers of too much specificity in online safety. We need to stop talking about individual cultural phenomena and platforms, and start talking about behaviours. In this case, what actually kept the family safe was a basic understanding of the risk of mains electricity, but this would have been a non-story if the family had understood Alexa’s role here as a mere messenger, relaying web content that was itself potentially unsafe, and Alexa was not endorsing the content in any way.

Read the excellent UK gov doc “Education for a Connected World” also explained here from SWGfL, and see how a focus on behaviours changes the narrative around online safety, and keeps us all safer.

Image from Education for a Connected World doc, summarising the content
Education for a Connected World focuses on eight behaviours (flipping the narrative from external risks to human behaviours).

As for the “journalists” reporting this as an “Alexa told my kid to do something bad” story… do better. And if you’re a teacher, I urge you to use this blog content in your classroom to have a discussion around the dangers of trusting AIs. And if you want to understand more about the issues and impacts of Computing for GCSE / High-school level teaching, read my book.


“Big church.” “Nice church.”

“Big church.” “Nice church.”

Typical comments perhaps from someone with few facts in their long term memory, when visiting a famous cathedral, according to blogger and primary teacher Solomon Kingsnorth in this tweet thread from 2018.

Kingsnorth suggests that with the benefit of a knowledge-rich curriculum, you might hear these comments instead: “Looks gothic, different to the baroque cathedrals I’ve seen.” or “I’m metres away from a tomb containing the heart of Richard the Lionheart. My own heart is racing.” Because as Kingsnorth explains: “To have facts in long-term memory is to have a private tour guide to the universe LIVING IN YOUR BRAIN, ready at a second’s notice to give you a plethora of information which will enrich your experience of everyday life.”

One might counter that the first person is still able to read a guidebook to learn about the cathedral, however the second person will still have the richer experience, because the guidebook will make more sense, its content triggering even more connections to existing knowledge which are recalled and enjoyed. Knowledge is both what we think with and think about according to English teacher and author David Didau, therefore more knowledge in long-term memory means richer life experiences.


I first encountered the idea that we “think with knowledge” in my second year of teaching (2017), when I first read “Why don’t students like school?” by cognitive scientist Daniel Willingham. Until then I had been a fan of constructivist thinking, very much beloved of Computer Science legend Seymour Papert, famous for the phrase “The role of the teacher is to create the conditions for invention rather than provide ready-made knowledge.” My attempts to replicate Papert’s alleged success with “learning through creating” were ineffective, however, which was unsurprising when I learned that “unguided or minimally guided learning is significantly less effective and efficient than guidance that is specifically designed to support the cognitive processing necessary for learning.” (Kirschner, Sweller and Clark).

Over the next year I read more on cognitive science and became convinced of its importance to my teaching practice. I moved schools from one where constructivist pedagogies were common, to a school which embraced “cognitive load theory” (CLT) including the illuminating notion that “understanding is remembering in disguise” (Willingham). The school values a knowledge curriculum too, and since joining my practice has developed considerably.

Back to our cathedral, and we can understand why the second visitor enjoyed a fuller experience if we listen to E.D. Hirsch who explained that “Learning builds on learning” and that existing knowledge acts as “mental Velcro” which allows new knowledge to stick to it. (Hirsch, 2000) Hirsch goes on to claim that “knowledge is the great equalizer, schools have … a responsibility to provide more equal life chances for all students [through transmission of knowledge]”.

Michael Young went further in 2014 to describe the types of knowledge that provide opportunities to succeed in life. Young (2014) explains that knowledge is powerful ‘if it predicts, if it explains, if it enables you to envisage alternatives’. Robbie Burns explains in his MA thesis (summarised in Impact here) how powerful knowledge gives “students the knowledge they need to go beyond their own experiences towards greater social mobility.” (Burns 2020).


I do believe that learning knowledge empowers our children to succeed in life and improve their life chances. But even if we sometimes fall short of that lofty aim of social justice, I also believe, despite the clunky nature of the phrase and it’s problematic origins, “the best that has been thought and said” is every child’s birthright. As Ben Newmark put it so eloquently in his book “Why Teach” and on his blog here: “We teach because … our children are the heirs of all that has gone before them and by teaching them well we gift them their birth right to the fruit of our civilizations”. Let’s give that gift, to the best of our abilities.


Passwords or pens: preparedness is a vital habit for life

I give sanctions for forgotten passwords. A C1 the first time and then a 15 minute detention for a second offence. Password resets are reasonably rare in my classroom as a result of this, and positive support for good password choices and habits – more on which later.

This tweet has 98 likes at time of writing, which means I am not alone in having trouble with passwords being “forgotten”.


In the tweet, like the above paragraph, I have put speech marks around “forgotten” because that’s the claim they make, yet often it’s not the case. Firstly, sometimes the error lies elsewhere – a mistyped username, for example. Students forget the username convention (how many letters of each name, what numeric prefix, whether we have included the hyphen or apostrophe in their name, something as a school we are not consistent about despite my best efforts), and therefore a password reset won’t help.

I find that this strategy works well:

  1. No password resets before the register. (This requires a DO NOW that either needs no computer use, or has an alternative activity that does. I have textbooks on the desks so they can pick one up and read about todays topic while I take the register). This rule gives the pupil more thinking time, and an incentive to remember the elusive password, and often they magically remember it, during this time.
  2. No password resets until I have watched their attempt to sign in. I often spot the error, such as a mistyped username. I also discover misconceptions here: we use Microsoft 365 and students often forget that if they have had their “365 password” reset, this will have synchronised to Windows also.
  3. If this support doesn’t result in a successful login, I will reset the password at the cost of a C1 and potential detention. I write the C1 and a note in their planner, and also get the student to take ownership of their error, by saying “I have forgotten my password”. I ensure they are disavowed of any notion that this just “happened to them” and that they made a mistake and must try harder. Passwords are, like a pen, exercise book or PE kit, a vital piece of school equipment and pupils must take responsibility for remembering it.

Good password choices

I get about one or two resets a week by this time in the year (December), out of over 300 students I see weekly. I think that’s a good rate, I know in the replies to my above tweet that other teachers have it worse. Maybe my September teaching and sanctions regime is working. In September’s first lesson I teach good password “hygiene”, basically:

  1. Choose a strong but memorable password. I insist on the adjective-noun-pad method, resulting in easy to remember but hard to guess combinations like Redgoose12 or Fluffyrat96.
  2. Write username and a password hint in your planner. A hint for Redgoose12$ might be r.g.phb$ (because BFF Phoebe lives at number 12).
  3. I give a second-lesson no-C1 grace period for forgetting passwords in Year 7 but remind them it will be a C1 next time.

I show this on the board to help with password choices, what would you choose from this list?



Whether it’s a pen, PE kit or password, if it’s an important piece of equipment, the pupils should get into the habit of coming to school with it. As shown above, once I have taught the necessary skills of choosing and remembering a password, sanctions are a vital extrinsic motivator to ensure they use those skills. Today it’s a pen or a password, tomorrow it will be (as I said on Twitter here) steel-toecapped boots, a security badge or, well, a password. We’re in the business of inculcating skills for life, so let’s get on with it.


HTTCS on tour – major update!

“You should do a book tour” said Allen Tsui on #caschat last night. I replied that I am doing a virtual tour! Scroll down for the evidence…


I recorded a series of YouTube videos with Craig ‘n’ Dave over the summer, the first of which is here. I then recorded the Learning Dust podcast with Andy Colley and Dave Leonard which is now live here.

“Unscripted” with Craig’n’Dave.

And my “CAS Inspire” podcast with Beverly Clark is now live here, alternative links here.

Also I have been busy with Edtech demonstrator work, delivering free training to schools via the United Learning Edtech Programme. If you need any help with Edtech: I can help as an official Edtech demonstrator, or with Computing: I can help as a CAS Master Teacher. Just reach out on Twitter @MrAHarrisonCS.


On not using mnemonics, and don’t get me started on crocodiles.

I’ve just seen another example of a mnemonic for remembering domain knowledge that reveals a potential lack of understanding of the subject matter, or a shortcoming in teacher pedagogy…

“To remember which binary shift does what, use this mnemonic: Lemon Meringue is Really Delicious – Left Multiply, Right Divide” (I have changed the mnemonic to protect the original poster).

I worry about any class learning this mnemonic as it suggests they are not being taught what binary shifts do, or why shifting multiplies or divides, and how this behaviour is exactly the same in any number base.

I teach binary by starting with place value and explaining how the places each have a value based on their position, which goes up by 2 each time as we move left, because we are in base 2, and show how this is exactly the same as in denary just with a different multiplier (10). When doing shifts I then do lots of worked examples in both denary and binary, and convert each binary result back to denary to illustrate the multiplying by 2 and dividing by 2 that is happening.


In this way, the binary number system becomes demystified – it’s just the same as base 10 just with different place values and a reduced symbol set (0 and 1). So they totally get that moving digits right (to the less significant places, the smaller column headings) makes a number smaller, and they understand that moving digits left (towards the more significant places, the larger column headings) makes it bigger.

Using a mnemonic suggests that the core concept of place value has not been taught or learned.

I feel the same about teaching greater than / less than by using “the crocodile eats the other number“, and about mnemonics like “rOm is nOn-volatile”. The < and > symbols are representations of growing and shrinking, the symbol is larger on one side than the other. Why add complexity with some notional crocodile? And ROM means “read-only memory” so it cannot be written to, so if it was volatile (lost its contents on power down) then it would be a pretty useless wafer of silicon as it would remain empty forever more. If they understand what ROM really is, and what volatile means* they cannot get this one wrong.

* I teach “volatile” with reference to Chemistry, where it means “easily evaporated”. If something evaporates it is lost, like the contents of volatile memory.


Relying on tricks can sometimes add complexity and confuse: One maths teacher told me that one of their students “got the greater than and less than symbols backward, because she believed the larger number would therefore be in the crocodile’s stomach after he ate it”.

Just teach the subject knowledge. Teach it well. And check for understanding. No crocodiles please.


Explanations matter.

Good explanations are vital to student understanding.

I pride myself on my explanations. Words are my forte (did you hear I wrote a book? 🙂 ) In my lessons I always explain the new material in a rigorous and deliberate manner, going back over tough concepts a few times, in a few ways, using analogies with familiar concepts, clearly enunciating any new terms and repeating them in different sentences so that the students get a feel for the new word and it’s meaning.

For example, protocols. I might start the topic of network protocols by explaining they are “rules for communication between computers, they make network communications work”.


I’ll then illuminate the concept of protocols by discussing the rituals people use when greeting a new person: they say hello, exchange names and use each other’s name when speaking, and so on. I then might say something like this:

“The rules of communication in polite society are a kind of protocol, a set of rules that make the interaction work. We follow a protocol because it makes everyone comfortable and helps communication be successful. The protocol tells us what to do when we meet people, and when we conduct a conversation. Establishing and following this protocol is important because it helps the conversation flow smoothly. Without any rules of communication which we call a protocol, meeting a new person and having a conversation with them would be quite difficult. Because both parties already know the protocol – the rules of communication – they can conduct a conversation with great success”.

I will then check for understanding with a few questions, using powerful questioning techniques from TLAC like “Wait Time”, “Right is Right” and “Cold Call” (unlike Ferris Bueller’s ineffective Economics teacher (see image).

I have so far used an analogy to introduce the concept of protocols in a familiar setting. I will then come back to discussing protocols in computer networks: being a set of rules for communication between computers that serve the same purpose – making communication successful – and in this way I have travelled a “Semantic Wave” to get the concept across, see this TeachComputing blog post for more on that.


But you will also note in my teaching narrative, I have used the word protocol no less than five times, in different contexts, ensuring students hear the phrases “follow a protocol”, “establish a protocol”, and “know a protocol”: it’s something to be established, known, and followed. They also know why: “helps communication be successful”.

Many teachers appear to be looking for that “magic lesson” which “drops the knowledge right into their heads from a PowerPoint slide”. Teachers: that magic lesson doesn’t exist but you don’t need it, you have all you need: your subject knowledge and a quiet class that listens to your explanations.


Exploring the Hinterland

There is great pedagogical value in exploring the hinterland with your students, as I explain in my article for Hello World magazine, issue 17 available as a free PDF here.

I shared a sneak preview of this article last month on this very blog. Now that it’s “out in the wild” it’s had some lovely reactions. Many schools are asking their teachers to add “cultural capital” to their teaching, and it’s a common misconception that this needs to be “bolted on” to the subject. Other conversations I’ve had reveal that many teachers think the “Issues and Impacts” or “Ethical, Cultural… Issues” topic in GCSE Computer Science is the only place you can teach cultural capital, after all it’s where we discuss the impact of tech on education and employment, the effects of eleectronic waste on the environment and so on.


My article (and for further reading, my book HTTCS) shows that there is cultural capital to be found across the curriculum, from linking Ada Lovelace to Byron and Mary Shelley, to Al-Khwarizmi’s influence in 9th C Baghdad, to the conflict between white settlers and native peoples in America’s west driving demand for the telegraph and eventually digital communications, cultural capital is everywhere in our subject. Read about it and share it with your students, your classroom will be enriched.