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This is the transcript of the podcast series 2 ep 001…

Alan: Hello, and welcome to how to teach computer science. The podcast. Back for a new series after a long summer break, , I had things to do people to see, but HTTCS is back with a bang. I’m calling this series two episode one, and I’m delighted to have Mr. Pete Dring on the pod today. Talking about physical computing and so much else. 

Pete: And then my Year 11s wanted to do a test launch on the field with a drone. And you’ve, no idea how much hassle it was to get permission to launch a drone on the school field and drop something from it. 

Alan: Are you near a flight path, or is it just the council going, you can’t do that? 

Pete: It’s because it’s the same technology that is used to drop drugs into prisons. 

Alan: We’ll be hearing more on that project later. But… So much has happened since last we spoke, we have new governments on both sides of the Atlantic. 

Yay. Um, Let’s start with our own election. When we binned off the Tories. Most of us would be happy with that, I think. did everyone enjoy Bindependence day? It seems so long ago now. Doesn’t it. What was your favorite moment? The demise of the haunted pencil. The lettuce being chucked in the green bin. Mine was probably Gillian Keegan being told by the people of Chichester. On behalf of all of us, but no, in fact, she hadn’t done a good job. I don’t know, but that seems a long time ago. Doesn’t it. Since then, over on the other side of the pond. America’s great experiment of dumbing down the electorate through defunding education has been hugely successful. 

I recommend turning off the news and going for a walk in the country I’ve recently got into geocaching. Yeah, I’m a bit obsessed, really. Whenever my wife and I go for a walk, I’m always looking for a cache. Then she gets a bit annoyed with me. She said to me last weekend, I think we should split up. So I said, good idea. We could cover more ground that way. 

Alan: My name is Alan Harrison, and I wrote the books how to teach computer science and how to learn computer science available in online bookstores. Also, if you like the podcast, you’ll love hearing me in person, visit HTTCS.online to find out more about my training and consultancy. And I could be speaking soon, live at your school on inset day. or AT your event or conference more details about this and book purchase links at HTTCS.online. That’s the initials of how to teach computer science. HTTC s.online listeners to the pod. Get a special discount code to just type HTTCSPOD in the checkout Page at johncatbookshop.com to get 20% off everything. That’s everything including classics, such as teaching walkthrus by Tom Sherrington. The Huh. Series by Mary Myatt. And of course my two little books. That’s with the code HTTCSPOD. At Johncattbookshop.com. 

Speaking of reading matter, does anyone want my collection of chiropractor, monthly magazines? I’ve got loads of back issues. 

So let’s meet my special guest Pete Dring and ask the fertile question. What is physical computing? 

Hi, Pete. We’ve spoken online on Twitter and various places, and I’ve used your stuff that you created, particularly during the pandemic. Remember discovering your little uh, exercises with explainer videos during the pandemic and they were really useful. How did that go for you? The dreaded COVID shutdown? 

Pete: Yeah, positives and negatives. I was chatting to some teachers yesterday at the swimming pool one of whom has, embraced remote learning completely and is working for an online school.

Another was considering thinking about the benefits of switching from traditional teaching because she just really enjoys imparting knowledge. For me, I just enjoy the classroom interaction. I got so frustrated just watching a wall of profile pictures with nothing coming back. Computer science is fascinating. I really like it, but it to me is not nearly as interesting as interacting with students. 

Alan: It was it was difficult, wasn’t it? The you knew that some of them weren’t really listening or weren’t even there, but there was nothing you could do about it during the online teaching that we did. Yeah, I remember there was lots of discussion at the time.

There was like crazy talk on Twitter. Teachers going, how do I force them to turn their cameras on and things like that? Yeah, it was difficult, but but you did lots of, explainer videos and little coding challenges.

Pete: we’re still using those, which is it grew out of a discussion between me and a local teacher in York. Like, how can we still support students to learn to code if we’re not in a room with them? So we wanted to have some short videos that they could engage with.

Obviously, we couldn’t check if they were doing it or not, but we wanted the motivation to come from them, but also some accountability in terms of tracking how much they did. So after putting together the activities that they could do we developed it to a kind of competitive leaderboard so that they could see how well they did compared with the rest of the class.

And that’s something that we’ve continued and developed post COVID. It’s a weekly challenge, something really simple. Like a type race with code that doesn’t really teach them that much from a computer science perspective, other than can I type without having to look at my fingers? But it’s amazing how much of a blockage that is for some students, especially who’s English isn’t their first language.

And then leading all the way through to independent coding from a blank canvas, but trying to trying to break the barriers at each stage between beginner and an end point has been a really interesting challenge. 

Alan: Absolutely, and you say about that type code challenge and my students love that and I think there’s much more value in that than maybe it seems at first. It gets pupils to really think about the syntax of the code and find all of the tricky punctuation symbols and stuff and I guess it teaches how precise they have to be. So they might in their head they know I need a for loop, doing the the speed typing exercises on your website would get them familiar with all that business of go print, open bracket and open quotes and all of that.

Yeah, getting the detail right. I suppose we should tell the podcast listeners that this is at your website, which is that particular set of exercises is live.withcode.Uk. Is that right? 

Pete: Yeah, that’s right. So the idea is each week there’s a. A short live coding video that goes from blank canvas to completed program, but rather than just giving the whole code, it invites you into the thought process of where it comes from, and it shows you that it’s not necessarily from line one to the end line.

It’s, it grows and it evolves. Most students don’t watch the video because I don’t need to explain why that is. But the easiest thing is that type race. It’s all about a low floor to entry. Anyone can do that without much mental effort. The challenge for me is trying to wean them off that and get them onto the debugging challenges and the code comprehension challenges and the extension challenges afterwards.

Alan: Cool, yeah yeah, so I, I would get them to do those exercises and then cut and paste what they learned into OneNote and then I would check it and stuff, um, yeah, that was all good. Back in the dark days, four years ago it is now the the old lockdown. I can’t believe how long ago it is. Yeah, 

Pete: it’s quite scary that some of the new teacher trainees coming through don’t obviously don’t remember teaching through that, but do remember being students through that. So their experience is completely different. I was chatting to a colleague who’s writing an article about, how much of schools learnt about, remote learning. Are we now better prepared for it? But we can’t assume that every teacher has been through it. It just made me feel old thinking that the new teachers coming through were on the other side of the screen. 

Alan: That’s quite frightening. I mean, it was an eye opener for me when I realized that the the kids that I was teaching had never heard of Nirvana, and that, that was like a watershed moment. , , how old am I? . I suppose I should. I always forget this, but I suppose I should introduce the podcast listeners to you, or in fact let you introduce yourself So Mr Pete Dring tell us a little about yourself and your teaching experience 

and, um. 

Pete: thanks Alan, and thanks for having me. I’ve loved the podcast so far. I’ve been teaching for 17 years now, I think. Started as an IT teacher in York, stayed in the city, love teaching in York. Initially started like part time ICT and part time learning support, and I loved that, really enjoyed the idea of a flexible qualification that just was, you shaped to the strengths of individual students, so that’s directed my career since then.

I’m now head of department at another school in York teach iMedia, computer science computing generally and yeah, generally get involved in lots of different clubs and competitions. I’m a sucker for anything free. If there’s a competition going where students can win something or I can win something, I’m all over it.

Alan: Yeah, good stuff. And like I said earlier, we we’ve chatted and exchanged ideas often on, on the socials and so on. so it’s good to have this chat and just toss some ideas around. The the point of today really was to talk a little bit about physical computing, wasn’t it? So I’ll just briefly tell you my experiences.

Not great to be honest in the classroom. I remember getting out the Raspberry Pis and thinking this is wonderful and then lesson going downhill very quickly. And yeah, so it’s difficult to use the Raspberry Pis. So I used the micro bits in lesson and had some great fun doing the rock, paper, scissors and stuff in lesson.

Micro bits are just about manageable because you’re not, at least you’re not unplugging mice and monitors and stuff. Stuff and trying to plug them into the Raspberry Pis, but I quickly moved all that physical computing to after school clubs where it was a bit more manageable with fewer students and more buy in from them, if you like.

And I like using microbit bitbot robots and we had races around the classroom. So that’s my experience. I wish I could have done more of it in the classroom, I guess, um, but uh, that’s why I’ve got you on, Pete, so you can tell me what uh, what you do with physical computing. First of all, tell us about What kit that you’ve been using, what’s available, what’s out there these days and what’s it good at?

Pete: Well, I’m afraid you’re going to be disappointed if you hold me up as a pinnacle of best practice in the classroom. But there’s a lot that I’ve seen done loads of mistakes that I’ve made but similarly, I find Physical computing works best as an extracurricular activity where you can invest in a smaller number of students.

But there are some tips and tricks to make it work in the classroom. You ask about kit. I think that’s a really interesting question. Your book actually gives a list of some kit in order of complexity. And I think that’s really helpful. So you mentioned Makey Makey, Crumble, Microbit, Arduino and Raspberry Pi.

So I’ve tried all of those. I really don’t like using a Raspberry Pi in front of students, because like you say, there’s so much that can go wrong. I like physical computing in a classroom where there’s just one device where every student can still use it. They can see it at the front. It’s easier to set up, but their code can still interact with it.

So Raspberry Pi can be brilliant for that if you’ve just got one. So like Raspberry Pi Minecraft is great. You can have the big teacher computer set up showing the Minecraft screen. Students can run code, simulate it on their own computer, so they get instant feedback. It’s easy to debug. But then they can collaboratively build a wall, like a 3D display. And they write code That sends messages, displays messages, makes 3D models. It’s a great way to illustrate data representation and and networking security. Yeah, that can be really good fun. 

Most of what I do in the classroom is probably with micro bits similarly. But the top tip I think is it comes from a primary activity. I put together a workshop for some local primaries and an SEN conference. And being able to run that conference, we got some money to buy a class kit that we could then give to local primary schools of these crumble computers. And if you’ve not come across crumbles, they’re like micro bits, but you use crocodile clips for them. And then they’re much simpler and primary friendly. 

But the breakthrough moment was making the setup and the pack away part of the learning activity. I think sometimes physical computing could be set up as this magical thing that all of us teachers feel guilty because we’re not doing quite enough of. But it can just sometimes feel like a bit of a bolt on that is a bit unnecessary. It’s, It’s kind of like the crowbar of trying to make our lessons fun for the sake of it. Which, you know, just makes me cringe a little bit. It’s not our job to make lessons fun. It’s our job to make lessons relevant and challenging and to bring students on.

So if physical computing is purposeful. Then it’s memorable and students learn so much from it. So with the crumbles, set up all of the equipment into small groups, let the students go into groups, and then their first instruction was to come up and ask for a little sparkle, which is a little RGB LED, and then they have to go back and a separate person in their team has to come up and ask for a set of wires.

And if they didn’t ask exactly as written on the instructions, I would say, no, I’m sorry, I don’t understand that instruction. And they had to say, please, and they had to say, thank you. And it meant that they got turned away because they didn’t understand their instructions. So the first teaching point was, okay, you’ve got to be polite to the teacher, but why?

Because instructions have to be explicit. You have to restrict yourself to that instruction set and that’s exactly what physical computing devices will do. And that was great because it meant that the setup and the pack down was well ordered and managed. It worked. 

Alan: Well, That’s brilliant. one of my next questions was going to be about behavior and that is how do you manage behavior when you’ve got all this kit out and you want it to survive to the next lesson, for instance um, I was talking to I think it was Dave Morgan and he said how he brought in a CPU to demonstrate just to share it around the class and unfortunately he brought in like 150 pound um, CPU that he was planning to use in a project and all the pins got bent and, and, and, you know, these things happen. So you don’t really.

Want your kit to be destroyed and yeah, that making, making the fetching, if you like, and returning of the kit part of the lesson is a great idea, I certainly know this, I needed to build in at least 10 minutes at the start and 10 minutes at the end for getting out and packing away, which doesn’t leave a lot of time if you’ve only got one hour for the lesson, but if you can get that. If you can put pedagogy into those 10 minutes as well, then what a brilliant idea that is. 

Pete: There are some other things that help too, like storage is really important. It took me a couple of years of teaching a physical computing unit with year nines to work out that actually handing out the tiny stubby little micro USB cables, they’re only about 10 centimetres long, separately to the micro bit was a waste of time.

We just keep the USB cables connected and tell them not to do that. Um, Have a box um, where they can all be put in compartments, have a student that hands them out at the start, and go round and make sure they’re all carefully put in their right compartments. Yeah, allocating time.

Alan: Yeah, you say about, get a student helper. I mean, this is where I used to have digital leaders. So you, your students, obviously the ones that are quite keen um, responsibility. I had, mostly in year seven, they would come at break time and say, sir, can I do anything for you? You know, I think, I think the school experience tends to beat that out of them at some point, but you know, year seven, and so you say, yeah, so be a digital leader and they go, Oh, what’s that mean?

And you go, Oh when I’ve got a physical computing lesson, you go and get the micro bits out and you hand them out and you get them back in and you get really keen students doing that. So, so it’s giving out some responsibility. As well . 

So why are we doing all this? If it’s so hard and needs all of this extra management over a lesson that’s just on the computers. Um, well, Why? It does. It’s got. extra work, extra planning and extra management going on, but um, there must be some benefits too. 

Pete: And expense as well. 

Alan: And expense. Yeah. Yeah. So why are we doing it? 

Pete: Um, so many reasons. I think you mentioned in your book that, which is excellent by the way um, that Uh, specifications for Key Stage 4, Key Stage 5 are put together from an assessment point of view.

You just get a dry list of topics and that tends to infect or influence certainly the way that we teach inevitably and the way And probably in a good way as well as a bad way. But it does mean that the links between the topics get lost, that hinterland, that the bits that make the course interesting and memorable.

And I think if you do physical computing, there will be things that go wrong, but there will be things that students will learn. Remember far more than anything else. I’ve got students who will remember activities that I’ve got. I’ve completely forgotten doing with them with the micro bit or a crumble or an Arduino or Raspberry Pi Pico or something.

But they remember what went wrong. They remember what they had to fix. They remember the the bridge between the topics. So one of the topics that I think is really hard to put in context and build those links between them is logic. And why are we learning about and, or, and not? I understand the concept , it’s quite easy to, to teach about truth tables and that kind of thing, but until you see the logic gates put together into a half adder, a full adder, and then actually turning into a mini CPU and then talking about the complexities, the restrictions and then how you can build that to make it more advanced, faster, more complex I think physical computing is memorable and it builds those links that makes what we teach memorable.

It’s fun, but you know it’s not my job to make students have fun. Fun is like the third on the list of priorities for me. I want them to be decent human beings and I want them to learn computer science. Fun is kind of a byproduct, but I’d like it to be memorable. 

Alan: Yeah, we’ve said this. So, the. The episode with Adrienne we went over this. I don’t know if you’ve listened to it, but she said, oh yeah um, we were, we were talking about teacher cliches and one of them, are we, are we having a fun lesson, miss, or haven’t we, are we having a fun lesson? And Adrienne and I both agreed. We say, all, our lessons are fun. You know, All my lessons 

Pete: Every time.

Alan: Yeah, but I’m very much a believer in fun comes from success, success is its own reward, being able to do something that you couldn’t do an hour ago, you try and build a culture , of achievement in the classroom and you value and you praise effort and achievement and, they start enjoying success. I made it work, Sir look, and that, that’s where the fun comes from for me because, I was talking to Dave Hilliard, I’m dropping names.

These are all people who’ve been on the podcast. Dave Hilliard we had a nice chat last week and it was about, algorithms and Programming being a creative art and how beautiful an elegant solution is, and that’s what we need to try and get instilled in the pupils, I think.

Pete: Yeah, I agree. And I think success doesn’t have to be individual. Success can be infectious. And the beauty of physical computing is that you have a physical remnant of someone else’s success that can inspire someone else. So some of the best projects have that wow factor that other students can walk into a room and say, what is that?

You actually built a satellite that went up in a rocket and wow, that’s incredible. How did that work? Can I do that? And it, it creates that sense of, yeah, I can picture myself. Doing something actually worthwhile rather than the intangible hello world or the even worse. Have you come across programming tutorials that mention foo and bar?

It’s a bugbear of mine. So, so abstract. It’s just abstract. 

Alan: Yeah, SoloLearn’s a bit like that. Um, It’s not bad. SoloLearn app if you want to learn a new language, but it’s all foo and bar. And. Yeah, and Snakify. Lots of teachers were looking in the last last few years for a self marking Python tutorial.

And Snakify was talked about regularly on Facebook, for example. I tried it and I hated it and my pupils hated it. It was all maths. It was, calculating the root of this number or the primes and working out primes and stuff. And it was just not relatable at all. 

Pete: And it’s good for some, yeah. Yeah. I really I mean, Anna Wake was talking about this in your episode about Mission Encodable and she mentioned the new the new level on Mission Encodeable, which is out now, and it’s incredibly creative. Really good. Yes, it’s great to see some practical, creative challenges, and that’s what I like again, about physical computing.

You can get students to do something that genuinely does have. Potential to make the world a better place. That’s the tagline for computing at my school. It’s, we want students to be able to learn the digital skills to make the world a better place, which sounds really airy fairy, but when you see devices that have won literally a thousand pounds for improving the environment or tackling mental health challenges or physical health challenges, then students can imagine, okay, what I’m learning in this computing lesson can genuinely make a difference. It’s really good. 

Alan: No, it is. Yeah, I must say that what I did was race buggies around and I’m not sure how that’s going to change the world, but uh, but yeah, sounds fun. Yeah, yeah, Yeah. But I’ve seen physical computing projects where, wearables is a good one where, you could put a micro bit on your shoe and count your steps and so on, but you could equally, make that sort of a movement detector for elderly people or something.

And if that micro bit hasn’t moved for an hour, then you can go and check on your elderly relative, that type of thing. So, so yeah, just the simplest idea can be applied to so many different contexts and some of them could be really important.

Pete: Yeah, I’d recommend competitions for that kind of thing. It can give focus to finding a purpose. There are some excellent competitions from ones that are really easy for students to get into, like Mission Zero, where you haven’t got physical kit in front of you, but the physical kit is on the International Space Station and you’re writing code to visualize images. Every student who takes part gets a certificate saying where the International Space Station was over the planet whilst it run their code. All the way to other competitions, which take a significant amount of effort, like the PA consulting Raspberry Pi competition. I think is brilliant. Every year you have a scenario.

So this year, it’s about medical technology. And I’ve got some year eight students who are putting together a Raspberry Pi device that measures. heart rate and pulse and ECG signals and body temperature and tracks all of that. And it’s great. The first time I did a competition like that was very labor intensive where I had to work with students and try and learn how to do it myself. And then this year, the students just do it themselves. They’ve taught themselves, they’ve got the kit, they work on it, they support each other. And it’s just brilliant to see the stuff that they can create and produce and share. 

Alan: That’s great. And you talk about medical devices there. That’s often one that’s cited that girls are more interested. What’s your gender balance like in these competitions? 

Pete: Yeah, good question. So last year, my team for the PA Consulting competition was all boys. So the challenge this year was to move from a sixth form team to a key stage three team and to have mixed gender gap. I run a STEM club after school which has built up over the last couple of years from, A really small group to now, I think we had about 120 students that applied for a place and most of those who applied were boys, but because I can only take 32 in the classroom, I can be selective and go for a 50 50 gender split and that’s been brilliant.

So most of what we do there is First LEGO League, where we use Spike Prime LEGO kits to, to solve problems, and that’s great to have girls teams, boys teams, mixed teams working together, sharing ideas realizing that what’s actually valued in the competition isn’t just the code, the code’s important. But actually a diverse team is so, so helpful for so many ways, just because you have different personalities, different strengths, different weaknesses sharpening each other.

Alan: Yes, getting the teamwork going is definitely something that physical computing can help with. So even going back to my bit bots, racing them, what I did actually was I got my DT teacher to build me an arena for racing the micro bits around, basically a maze, an adaptable maze. So you could make a maze of any shape. And we raced the bit bots around it. And I the bit bots were from 4Tronix. I think if you search them, there’s also Kitronik and obviously Pi Hut and PiMoroni and lots of other places you can get these things from. But basically the micro bit slots into it, so you program the micro bit and if you go on make code, the block coding interface for the micro bit, there’s already extensions for the bit bot, so get all these blocks that say, drive forward, turn left and so on.

So it’s easy to just block code the instructions for the bit bot and then you plug your micro bit into the bit bot robot, which is a little buggy. Which drives around the maze. So they were trying different strategies for getting around the maze as quickly as possible. And, I’ve got some videos up on the school YouTube site of the shouting and screaming when they were um, being successful.

so that was great. And there was two ways Two or more different strategies they could use. There was just hit and hope, as in when you hit a wall, bounce off, turn and see if you can go in that direction. And then I offered them the ultrasound sensors, which could sense how close they were to the wall, and they could use them if they wanted.

And it was great to see different, using different inputs. to to the algorithm and deciding what to do. Yeah, so that was just robots around a maze, which my lot enjoyed and it didn’t cost a huge amount. But again, I did that in after school clubs because I can’t see that being very easy in a lesson but it got the teamwork going and so they were working in at least pairs and You know, there was lots of conversations all about algorithms in that room.

So that’s what you can get going. Yeah. 

Pete: And presumably that board, that six by three board was something that other students could see. It might only be a small number of students who come to the club, but the after effects of the buzz of that and people talking about it and the ability to use it at open evening, it has a much wider impact.

Alan: Yes. Yeah, so the board because of its size was usually visible in all my lessons. . Yeah. So, so yeah. Oh yeah. That’s the maze arena. For, and that did work. it did work as a recruiting tool, I had the robots on my windowsill as well, so they could be seen by in the playground and stuff. So, um. so yeah, that worked. 

Pete: So don’t misbehave in Mr. Harrison’s lesson or he’ll put you in the maze and you’ve got to find your way out. 

Alan: Yeah, we need a life size one, don’t we? Um, so what was, what’s the best project you’ve seen done? What’s the best physical computing project you’ve been involved in or in fact seen?

Pete: Great question. There’s so many really good ones. The best one I’ve been involved in recently was CANSAT, which is sponsored by the European Space Agency and done through STEM learning. Have you come across that at all? 

Alan: I’ve seen it online, yeah. 

Pete: It’s it’s quite a complex competition. So there’s upper Key Stage 4, Key Stage 5, it would be most appropriate to. I had a small team of sixth formers that were involved this year. And we used two Raspberry Pi Pico devices. So with a Pico, you can code it with MicroPython or CircuitPython and you. You have to make a can sized, a drinks can sized satellite that will go in a rocket and it gets launched a thousand feet up into the sky, it takes sensor readings and then beams them with a long range FM transmitter back down to Earth.

So you need one Raspberry Pi Pico in the satellite, another one down on your ground station, and you have to transmit the data, receive it, process it, and then visualize it. And it’s fascinating, absolutely fascinating, because you’ve got to focus on the physical aspect, like a parachute design. You have to focus on building the satellite itself, then prototyping it, trying to make it robust enough, because the G forces when it launches And then when it starts to to descend are significant and then you’ve really got to focus on the robust code for it.

So for us, we managed to get the code working and it received all the sensor values, but we hadn’t ever really tested it in the field at a thousand feet up in the sky. With other people transmitting on the same frequency. So we got some data, but it was partially corrupted and it just brought home to the students how essential it is to make your code reliable and robust.

But even outside of the students who were involved I got some year seven students involved in writing some code to to work out the best size of the parachute , it linked into some Year 8, Year 9 lessons for designing a logo for the team. And then my Year 11s wanted to do a test launch on the field with a drone. And you’ve, my goodness, you’ve no idea how much hassle it was to try and get permission to launch a drone on the school field and drop something from it. 

Alan: Oh, no. Are you near a flight path, or is it just the council going, you can’t do that? 

Pete: It’s because it’s the same technology that is used to drop drugs into prisons. So you have to get through so many levels of risk assessments and permission. But it was so worthwhile, it’s good fun. 

Alan: Okay, that didn’t occur to me. Now I’m wondering whether, there could be year 11s and beyond with a lucrative sideline in drug running into prisons now. 

Pete: Well, There’s always an option.

Alan: Could be a downside of that project. 

Pete: Or exploring a route out of teaching, who knows if this all gets too complicated.

Alan: Nice one. So. this is all very well, all this fun as we keep saying, it’s not about fun. It’s about learning. How does all of this contribute to the learning that you want them to do? And sadly, we said, the tick box objectives of the curriculum and the assessments they’re going to do eventually, is it all worthwhile?

Pete: I think so. As long as it’s done in a purposeful way and in a manageable way, students know instantly whether something is just a token activity. So, I find that simulating before using physical kit is really helpful, especially for things like micro bits, where you can have an on screen simulator, either with blocks or with Python codes.

And that takes the frustration of, behavior management of. of handing out the kit, collecting it out at the end. You can teach them about the benefits of instant debugging is really hard, actually to debug a code on a Raspberry Pi or a micro bit. If you’ve just got the device in front of you and a simulator is really helpful for that, but it’s nowhere near as satisfying or as applied as if you actually plug in the physical device and hold it.

So It’s about trying to draw out the learning objectives really clearly at the start of the lesson and then link it back and keep referring back to it. So you’re referring back to when the micro bit didn’t work, giving that as a practical example that students can relate to when they’re debugging in future.

I do think it’s worth doing, but I don’t do it very regularly just because it’s expensive in terms of time and preparation, but once you’ve got a project that works it can be repeated and scaled up. Like we’ve got class sets of micro bits now and talking about networking We can talk about network protocols, we can talk about packet sniffing, but if we do the theory first and then a 20 minute activity where students write a bit of Python code to send using the radio module in a micro bit and then receive it, turn it into a remote control for a device and see the potential for somebody else to send another packet that will then interfere with it.

It brings the theory alive in a way that, yes, is fun, but ultimately I need them to be able to remember it and apply their understanding. And that’s where physical computing comes into its own. 

Alan: Absolutely. Yeah, it’s that sort of, that hook to hang things on and, that memorable lesson and if you’ve read anything by Peps Mccrae he’s got a book called Memorable Teaching and it’s probably the best hour of reading you’ll do in your teaching career to be honest because Peps Mccrae’s books are very short but absolutely jam packed with great advice and memorable teaching and it’s, it’s about creating those memorable moments which are almost like the seed of a schema that you can build upon and, the really solid hooks that you can build on because you’ve got that lesson where this thing happened and, Like you say they made the links between programs and logic and input and output all in one lesson and have something to hang the, the theory on if you like.

Pete: No, I’ll look out for that. If you can post a link in the show notes, I’ll I’ll have a look at that book or that paper. 

Alan: Yeah, Peps Mccrae is brilliant. He’s got a series of four books, I think, that are really short. Like I say, they’re only like 70 pages or something, and you can read it in an hour or so. And Memorable Teaching was the one that I remember. Nice. 

Pete: That must have worked. 

Alan: Yeah, I will. I’ll pop that in the chat and on the blog. So yeah, so what are you up to? I assume you’re on Easter holidays at the moment. 

Pete: Yes, so Easter holidays for me means procrastinating and pretending that I’m marking my coursework for A level and iMedia and failing miserably at it and trying to find any excuse not to actually knuckle down.

Alan: I must admit, as a former teacher of iMedia, I feel your pain there is a lot of marking. And a previous guest and I were talking about this the workload in the vocationals for teachers, but also for pupils, the amount they have to write.

And there’s a lot of talk about gatekeeping of computer science, GCSE. And a lot of schools still do this. Oh, you can only do it if you’ve got target six in maths and all of that. And then a lot of schools. push those children without a target of six or above in maths onto the vocationals, believing that they’re easier.

And vocational qualifications in IT, which include, I suppose, Creative iMedia is IT adjacent, and the Cambridge Nationals and the BTECs and all of those. I always find that it’s just full of written work. They have to research and write things up, and that can be very difficult for the lower prior attaining students.

Pete: Yeah, completely. I mean, in theory, and also in terms of principles, computer science should be for every student and anyone should be able to take part in it, but also the vocational qualifications should also be for everybody and they are really quite challenging at the top end. There’s a huge amount of extension and then not that easy at the bottom end.

You’re right. There’s a lot that you, especially if If you do them as you’re supposed to do them, the iMedia qualifications, we’re not allowed to tell students what software to use, what tasks to do in what order. They have to be self managed and that’s really hard for some of my weakest students to, to read and interpret and work out what to do.

It’s. It’s so frustrating when you see students just missing something obvious because we’re not allowed to tell them how to approach the work they could organise themselves. 

Alan: Yeah, I remember doing things like researching different software and so on and and they would just Google stuff and write what they read because, how would you research what software to use, yeah, I agree. But we got Off the topic a little bit. So you’re avoiding marking. Why don’t you give all your marking to AI, Pete? Why are you doing it yourself? 

Pete: Yeah, I mean, thankfully the qualifications have got better so that the initial research task is removed now. But I probably do spend far too much time thinking about how could I simplify this? How can I? Make a robot that will mark for me rather than actually just knuckling down and doing the marking in the first place. 

Alan: Yeah, unfortunately you, you are running a vocational qualification with tons of coursework so that there’s no easy way out of this. But yeah, I was being facetious about AI just now. It does make me sad when I see teachers talking about using AI to mark and to create reports, as in sending reports to parents and I just think we’re automating the wrong things. I worked in a school that didn’t do reports. What we did was had a principle that we would get in touch with parents if there was anything they needed to know, and then we’d have one parent’s evening, which went virtual, of course, during COVID, and stayed virtual.

So it was online. So there’d be one online parent’s evening, and that was it. And I think that’s fine, because all you need as a parent is to know whether your child is happy, whether they have any issues that you need to deal with. Otherwise, that’s. That’s about all I ever needed to know. I didn’t need to know whether they were at, the old level 4B or whatever replaced it, which in a lot of schools was just another version of level 4B, you know, but I didn’t need to know that. I needed to know, are they working hard? Are there any barriers to their learning? Are they happy? Are they being bullied or whatever? Beyond that, I trust the teachers to get them to do as much progress as the teachers can get them to do, and that, and so automating reports. And oh, I’ve got this ai, it takes my one liner which has a grade and an effort and a topic that he’s not good at. And it turns it into 500 words of a report. And I’m thinking, if I’m the parent receiving AI generated 500 words. , I’d rather the one liner, please. 

Pete: Absolutely. 

Alan: If that’s all the teacher knows about my child, send me that. Don’t get AI to make up 500 words. 

Pete: What you can imagine next is a program for parents that will take AI generated content that’s 500 words long and simplify it down to one sentence that is exactly what the teacher thinks about your child.

Alan: yes, James is an enthusiastic boy, but sometimes his enthusiasm leads him to make teaching difficult or whatever. And you think, right, what did the teacher mean by that? He’s naughty, right? He’s disruptive. Okay. I’ll phone the school and find out what the truth is, so then AI for marking. I remember there was a Dragon’s Den episode. Have you seen MarkMate? The guy was on Dragon’s Den and basically you dictate into this machine and it 

Pete: Yeah, I have seen this.

Alan: Automates written marking of books and I’m thinking just stop because I don’t know about you But I do very little marking when I’m teaching I did lots of multiple choice quizzes lots of retrieval practice lots of in lesson feedback I would walk around and see how they’re doing and give them Tailored feedback verbally regularly so they had tons of formative feedback and then I’d do a summative test once a year multiple choice quizzing using either Microsoft Forms or something. Yeah and that was enough for me, that was more than enough for me. So formative feedback has to replace all this written marking and in a lot of schools it has done. 

Pete: Yeah, no, we have to be wise and kind to ourselves about what is possible and what is beneficial. We deliberately have a feedback policy rather than a marking policy because the amount of marking we have to do at Key Stage 4 and Key Stage 5 is so huge, we need to create capacity for that and use the technology to, to give feedback where possible and, Prioritise time for what students actually value, which is the motivational feedback, the well done, you’re doing a great job, or come on focus, this is how you can improve, the verbal things that actually make an impact.

We’ve been doing a a study with the Raspberry Pi Foundation an action research project on the impact of different types of feedback in computer science. And that’s been fascinating because we do a lot of different types of feedback, self reflection confidence ratings, um, assessment for learning automatically generated assessment.

And we asked students what makes the biggest impact on your motivation? And what makes the biggest impact on how equipped you are to actually do something about it? What informs you about the next steps and what they said and what we thought were completely different. So that’s challenged what we do to try and free up some extra time to focus on what students actually find beneficial so that we don’t waste our time going through books ticking and flicking but do invest in individual feedback where possible and where beneficial. 

Alan: Yes, a feedback policy. Feedback much greater than marking and definitely. So again, we got off topic. So we need to have another conversation another day about all that stuff. But as for today, that’s been brilliant, Pete.

Thanks for coming on. 

Pete: Thank you so much for having me on the podcast and thank you for all of the nuggets of information and context and hinterland that we can all glean from your book. Really helpful. 

Alan: No, you’re welcome. It was a labour of love. I had it in me. I had to get it out. So, yeah, and obviously there’s a learn book as well for students. I don’t know why I’m showing it on the podcast. But, yeah. Yeah, that’s great podcasting, Alan. Well done. So yeah, don’t forget the learn book for students which Dave Hilliard was involved with. He wrote the foreword, that’s Craig and Dave’s Dave, of course, and he wrote the foreword and he proofread it.

So I’m grateful to him for that. So if you have very scholarly students, or even if you don’t, you could buy them a class set. That would be really kind to me and kind to your students. But yeah, thanks for coming on, Pete. lovely to talk to you. The sun’s come out, so I think it’s time we we wrap up. 

Pete: Great to see you. Thanks for making time. All the best. 

Alan: And you, Pete. Lovely to talk to you. Take care. Bye. Thank you. 

Pete: Bye bye. 

Alan: Well, that’s a wrap for another pod. What a great chat with Pete. 

 Some sad news. My mate’s funeral is tomorrow at 9:00 AM, but I’m not going. He knows I was never a morning person. 

 Talking of funerals, there was an incident last week when the man who invented USB sticks was being buried, the coffin got stuck going into the grave, but they turned it around and it fitted perfectly. 

Quiet, correct horse battery staple. He’s quite angry at all the name changes. Well, he would be he’s a cross breed.

 Don’t forget podcast listeners can get a 20% discount off all books at johncattbookshop.com with code HTTCSpod. If you already have the books, buy me a coffee, please at ko-fi.com/mraharrisoncs, all links are on my blog at HTTCS.online/blog and subscribe now so you don’t miss a thing. 

 This is the start of series two. More to come next week. Have a great week and I’ll catch you next time.

I had a brilliant day last week as a speaker at the inaugural “Craig’n’Dave and Friends” conference. Hosted by the inimitable Johnny Palmer at Bromsgrove School, I was treated to keynotes from Miles Berry on AI and from the chaps themselves on the future of SmartRevise (TL;DR – it’s getting some amazing superpowers!)

My talk was well attended both times, and I did promise I’d post the slides here, but they are already available on the conference website here

The conference will be back next year, check the CnD website for details!

The transcript of episode 2 of my podcast is here!

Transcript:

Hello. Welcome to how to teach computer science, the podcast. 

 This is episode two. They said it would never last. What is computer science? Is the title of this episode, the one you’ve been waiting for no need to study for three years, or even do a SKE for six weeks next summer. Just put this on, repeat for a few days and you’re done. Heh, my name is Alan Harrison. I wrote the books how to teach computer science and how to learn computer science available at many online bookstores. And you can find out more details at the companion website httcs.Online. That’s the initials of how to teach computer science. HTTCS. Dot online. I’ve got 25 episodes planned, which will take us up to the summer holidays and some fab guests booked in including drum roll, please. 

 Andrew Virnuls of advanced-ict.info. Adrienne Tough, Andy Colley, Beverly Clark and Harry and Anna Wake from mission encodable. Looking forward to inviting those fantastic people onto the podcast in a few weeks. There will be parables practice and pedagogy in this podcast. And a lot of computer science, subject knowledge and more jokes probably and anecdotes and other fun stuff like competitions and prize draws. As I was writing this script. Yes. I wrote a script. Don’t be rude. The thesaurus packed up in Microsoft word. So I have no. Thesaurus now, which is terrible. It’s also terrible. 

Oh, no. Now the dictionary is gone as well. I have no words. 

If you want to give me feedback. On that. Or anything else? Or get involved, just go to HTTCS to online or check the show notes. 

I’m also on threads Mastodon and X. mraharrison, or you can email me alan at HTTCS dot online. Remember, if you liked this content, please subscribe. Tell your friends, buy my books, leave a review on Amazon. Or at the very least buy me a coffee. At ko-fi.com/mraharrisoncs details at HTTCS dot online. The transcript will be on the blog as normal. That’s HTTCS online slash blog. 

So if you don’t like my voice. You can get your favorite text to speech engine to read out my words. Who’s this. 

Alan’s podcast is essential listening for me. I tune in every week. There is no life I know to compare to pure imagination.

Alan: That was Willy Wonka actor gene Wilder. Bye Gene. Thanks for popping in. I wonder who’ll be on the show next week? 

So let’s get today’s episode going with another fertile question . If you don’t know what that is, go back to last week’s episode. So today’s fertile question 
what is computer science? I’m now about to tell you in under 30 minutes using the TLDR sections of each chapter in the book, if you’re not terminally online, like I am, you might wonder what TL semi-colon D R stands for. It is of course too long didn’t read and you’ll see it if you dare post anything longer than a tweet on any internet forum these days, kids just don’t have the atten-. 

So here we go then. What is computer science?

 1. Data representation. 

The heart of this topic is the idea that if we can turn information into binary data, We can use a computer to process it. Digital computers process binary numbers, because they used to state electrical signals the chMastodonges, therefore to find a transformation for real-world information to binary, this transformation is called encoding and it makes use of a code. ASCII and Unicode are used to encode text. JPEG GIF [00:04:00] PNG do the same for bitmap images and wow. MP3 and AAC and code digital sound. But it’s important to realize that there are virtually limitless ways of encoding information. 

And these are just the techniques that are widely used. Oh into that effectiveness or official recognition or both. I’d love to digital conversion is the process of mapping the original data to the digital representation. And it’s vital to understand binary, to really grasp the importance of that debt resolution and their effect on file size. Metadata is data about data and describes the contents of the file or something about the original information. That’s really the fundamentals of data representation covered. 

The most important concept is we need a way of encoding information as binary. Then we’ve cracked it. 

Talking of binary. I made a worksheet for my class full of binary number questions then I went and guillotined the right-hand edge of all the [00:05:00] pages. Chopped off the last digit on the right, other side of all the binary numbers on the worksheet. But it didn’t matter, why? 

That’s today’s competition. 

Find my tweet, threads post or Mastodon post entitled “podcast competition” and answer this question. Why did it. Not matter that I chopped off the last digit of all my binary numbers? 

 Onwards and upwards. Let’s talk about. 

Two. Programming. 

In 1968, Donald Knuth wrote, the process of preparing programs can be an aesthetic experience, much like composing poetry or music. Thank you, Mr. Knuth Renowned Dutch computing pioneer Edsger Dijkstra is famously supposed to have said, computer science is no more about computers than astronomy is about telescopes. 

Although this isn’t on record anywhere, but he did say surgery isn’t called [00:06:00] knife science. Programming is not about devices or even key words or punctuation or indentation. Programming exists to solve problems using machine. First we find a way to state the problem computationally. Then we get a machine to perform the computation. The first part is what we now call computational thinking. It’s easily the largest part of the process, but novice programmers often forget this. 

And sometimes expert instructors do too. Programming is about using abstraction to determine inputs, processes, outputs. And deciding which variables and data structures are needed. Then using decomposition and algorithmic sinking to design an algorithm to process the data. You will need sequence selection, iteration, and sub programs, which you will combine in a structured program. Remembering to make it maintainable with meaningful white space and the use of sub programs, that’s functions and procedures to break a problem down into smaller problems that’s [00:07:00] decomposition. In all programming instruction, developing computational thinking or CT skills is where we should spend our time. And we heard last week that in all teaching, we should consider cognitive load and make sure learners are thinking hard about what matters, getting better at designing programs, using CT and not about working out where the punctuation goes. This is why when we’re teaching programming, we should do lots of code comprehension. 

We should use PRIMM. Parsons problems. Sabotaged code. Smelly code and pair programming to reduce cognitive load and I’ll be discussing all of those in a future podcast. 

So that was programming, but we need to make with our programming skill… 

Three. Robust programs. 

Early program mes designed and debugged their own programs. Building in code to prevent failures due to user error or hardware failure was pioneered by Margaret Hamilton for the Apollo space

program. Her work led to the creation of a new discipline, software engineering popularized by a NATO conference in 1968. New techniques and tools were created throughout the seventies to address the software crisis and improve software quality. Glenford Myers published the art of software testing in 1979. And the software development lifecycle was born.

Industry found The original waterfall development model, unresponsive to change. And iterative techniques known collectively as agile grew popular in the 1990s. Many companies began to employ test automation, software to reduce costs. Modern robust programming techniques you need to know include. Anticipating misuse through authentication, access levels, sanitization and validation. 
So let’s look at those. Authentication is keeping out unauthorized users by verifying the user’s identity usually with a [00:09:00] password more on that in the cybersecurity episode coming soon. Access levels limit what a user can do to their permitted functions. Input sanitization, such as removing spaces and punctuation prevents bad data getting in and defend against SQL injection hacks. Again, more later in the cybersecurity episode. Validation checking inputs are reasonable. For example, the birthday to the living person must be sometime in the last hundred and 50 years, right? 

Robustness also comes from structured programming techniques, focused on modular maintainable code that uses meaningful identifiers, indentation, white space and sub programs. 

Testing is also important for robustness. Iterative testing is carried out during development and final testing at the end. Black box testing means treating the code like a black box we cannot see into, instead checking each input causes expected output. White box testing, which should actually be called transparent box [00:10:00] testing, describes testing with knowledge of the code. 

For example, you might run tests that ensure every line of code is executed. Do not confuse white and black box testing with white and black hat hackers. They are not related.

Languages and IDEs. 

We need to remember that at its heart a computer is just a collection of logic circuits that process digital signals of high and low voltages representing zeros and ones. The circuits can decode patterns of zeros and ones, and we call these bit patterns. Instructions. Each CPU responds to a finite set of these low level instructions, its machine code instruction set. 

Coding in binary is difficult and error prone so each binary code is given a short, memorable name or mnemonic such as load add or branch. This assembly language is still difficult to code and contains no useful constructs, such as [00:11:00] loops or arrays. So high-level languages were invented, which are more English like, and allow us to write complex programs very quickly. Python Java JavaScript, VB.NET, ,CC plus plus, and C sharp are popular high-level languages. 

High-level code must be translated into machine code before it can be run on the CPU. For this, we need a translator. Compilers translate the whole high level source code program into machine code creating an executable file of what we call object code. Interpreters translate the program one line at a time which allows for rapid coding and debugging but slower execution than compiled code. Assembly language may still be used for small mission critical programs because machine code compiled from high level code may not be optimal. an integrated development environment or IDE is usually used to develop code. An IDE provides many features to speed up coding and debugging, such as syntax [00:12:00] checking autocomplete, stepping break points on variable tracing. As an aside, my favorite ID for beginners is now Thonny, from Thonny.org.

Algorithms.

Earlier we heard that programming is not about using the correct keywords if while and, so on but the process of solving a problem with the building blocks of code, sequence, selection, and iteration. Algorithms predate computer science by thousands of years and derive largely from mathematics and the natural sciences. Indeed the word algorithm comes from the name of a Persian scholar. Muhammad ibn MÅ«sā al-KhwārizmÄ« who worked in Baghdad in the ninth century. Some algorithms are so useful, they crop up again and again so an understanding of searching and sorting algorithms is necessary. The bubble sort algorithm passes over a list or array of data, many times repeatedly swapping, adjacent items. Insertion sort maintains a sorted and unsorted sub-list, repeatedly picking the next unsorted [00:13:00] item and placing it into the correct place in the sorted sub-list. Merge sort breaks a list down to individual elements, then recombines elements into sorted pairs, pairs into sorted fours and so on. Until the list is whole again and sorted. 

As for searching. Well, linear search just checks each item in the list until it finds the target and this works on unsorted data. If our data is sorted, we can use binary search, which repeatedly checks the middle item and discards the left or right half of the array each time, which is much quicker. As we can see two or more algorithms can be created to solve the same problem. And they will perform differently given particular inputs so it’s important to choose the right algorithm for a task. Learners must also be able to interpret an algorithm from flowcharts and pseudo code, correct errors and complete unfinished algorithms. To help with all of this, they should be able to trace an algorithm, thus driving out logic errors. 

Okay. Little break [00:14:00] now let’s play the high, lower game. 

 I’m thinking of a number from one to 64. Guess what it is. Oh, I’ve got a text here from a listener. I’ll text to speech it. 32. Ah, you’ve played this game before, haven’t you.
Lower? 16.
Higher. 24.
Higher. 28.
Higher 30.
Lower. 29. 
Correct. It was 29. 

Well done. Random listener on the text message there. Yes, no matter what number I choose between one and 64, you can guarantee to get it in six guesses or less. It’s one of my party tricks in the classroom, but why is this? And what has it got to do with algorithms? Well, you can message me. Just for fun. To tell me the answer or I’ll give the answer next week.

Architecture. 

Alan Turing described the concept of the stored program computer in [00:15:00] 1936, John Von Neumann built on Turing’s work explaining in 1945 how a cycle of fetch decode execute could allow the same memory to hold programs and data. Freddie Williams led a team at Manchester university that built the baby. Which ran around 700 instructions per second in 1946. Its success led to the 1951 Ferranti Mark I, the first commercial computer, for which women wrote most of the programs. Valves gateway to much faster transistors in the 1960s and this exposed the Von Neumann bottleneck solved by the Harvard architecture of separate memories for instructions and data. 

Early memory stores included paper tape, magnetic tape, magnetic drum, acoustic delay lines, and core rope memory until semiconductor RAM arrived in the 1960s. Magnetic hard disk drives provided secondary storage from the 1950s onwards with flash memory becoming popular in the 21st century for portable storage devices and solid state disks. Compact discs invented in [00:16:00] 1979 and DVDs and Blu Ray disks are examples of the third common storage type, the optical disk. Computer performance is limited by the three CS, clock speed, Cores and size of cache. 

From the baby to the modern smartphone, all CPUs still contain an arithmetic and logic unit or ALU, some registers and a control unit. And they perform a fetch decode execute cycle first described by Von Neumann in 1945. Talking of Von Neumann, I’m saying NOY-mann because he was Hungarian. And not to be confused with Max Newman who worked at Bletchley park with Alan Turing. So von Neumann thank you for your contribution. And inventing the arithmetic and logic unit, talking of logic. 

Boolean logic.
George Boole published his paper, in 1847. Describing what became known as Boolean algebra. Claude Shannon [00:17:00] saw how Boole’s work could be applied to electronics in 1938. The first digital computers used fragile valves and slow relays. Transistor computers arrived in the 1950s, greatly improving speed and reliability. Computer’s use a high voltage around five volts to represent either true or a binary 1. And a low voltage close to zero volts to represent False or binary zero. A transistor acts like an electronic switch, turning the voltage on or off. Transistors can be combined into logic gates. A logic gate is a collection of microscopic transistors that perform a Boolean logic operation, such as, AND, OR or NOT. Logic gates are combined into circuits, inside a computer to perform arithmetic and logical operations. An AND gate takes two inputs and produces the output one or true only if both inputs are one or true. One input AND the other. The OR gate produces an output one, if either one OR the other input is one [00:18:00] and a NOT gate inverts the output zero to one and one to zero. We use truth tables to list the outputs for every possible combination of inputs. We can write Boolean expressions, such as Q = A AND NOT B, and then draw logic circuits, connecting symbols, which represent the logic gates. 
Hey, talking of logic. Three computer scientists walk into a bar, the bartender asks, do you all want a drink? The first says, I don’t know. The second says, I don’t know. The third thinks for a minute and says, yes. If you know how that works, message me on threads, Mastodon or X. Just for fun.

 Eight.
 System software. 

Early computers were hardwired to perform a single program. Running a different program required extensive manual intervention. An IBM project called stretch in 1961 and Manchester’s Atlas computer in 1962. Provided multi programming features for the first [00:19:00] time. In 1964. IBM’s 360 delivered index data files, program libraries, a job scheduler, interrupt, handling, and print spooling. 

The modern operating system was thus born Two Bell labs, researchers, Ken Thompson and Dennis Ritchie created Unix in 1971, which became the most popular OS on the planet by 1980. Apple’s 1984 Macintosh was the world’s first successful home computer with a graphical user interface. And a year later, bill gates, Microsoft released its first GUI called windows. Mobile versions were spun off in the 21st century, including iOS and the windows Phone OS. Which is now dead. The Finnish student. Linus Torvalds released the first version of Linux in 1991 and it now runs hundreds of millions of devices from home internet routers to Amazon’s data center servers. Linux is open source, meaning anyone can see copy amend and contribute to the source code. OSs are a [00:20:00] type of system software that exists to manage the hardware and to allow applications and users to interact with and control the system by managing memory, CPU time slices and input and output. 

Utilities and drivers are also system software. Utilities help keep the computer running smoothly while drivers communicate with the hardware. Anything, that’s not an application is probably system software.

Nine.
Networks. 
 Let’s quickly look back at the creation of the internet. 
The internet, is that thing still around?
And then the worldwide web. In the 1960s computers on university campuses like UCLA would join together in a local area network or LAN. Then in 1969, the first wide area network or WAN was created between UCLA and Stanford as part of the ARPANET project. Early routers called interface message processors or IMPs performed packet, switching the process of breaking up data into chunks and routing it [00:21:00] across a network with the packets potentially taking different routes. And being reassembled at the other end. This was a key strength of the ARPANET, allowing it to grow quickly and perform reliably. In 1983. The ARPANET adopted a set of standard protocols created by Vint Cerf called TCP IP. Protocols are rules that enable very different computers to communicate. The protocols are arranged in layers with each layer, performing a single job. 

At the top is the application layer where email sits and later websites displayed by the browser. Throughout the 1980s, the internet was used mostly by universities and the military to access text only services like email, FTP, and use net. Home users arrived on the internet in the early 1990s. Thanks to the first commercial ISP, including AOL and CompuServe. 

True story. I sent my first email in 1986 from Sheffield university to my friend at Newcastle university. But within weeks of starting, my course, our email [00:22:00] access was removed because we crashed the server with chain emails, full of ASCII cows. Google ASCII cows and thank me later. Tim Berners Lee combined HTML with TCP IP to create the worldwide web in 1993. This technology allows a browser to download and display pages from a web server anywhere in the world. The web has grown rapidly and around 66%. of the world’s population is now online. 

 It’s important to draw a clear distinction between the internet and the worldwide web. The internet is a global network of cables, satellite links, switches, and routers that join computers together. The web is the collection of websites, apps, and services that make use of the internet to do useful things. 

Alan: Computer networks can be LANs consisting of switches, wireless access points, and Ethernet cables or WANs which use copper, fiber optic, microwave and satellite links to join devices over long [00:23:00] distances. a Router connects a LAN to another LAN or a WAN. The router in your home is actually a multifunction device containing a switch, wireless access point, router and modem. Right. So what’s next. Oh, I think there’s another celebrity guest.

Cybersecurity. I don’t know much about that. Don’t worry, Peter. I do .
Ten.
security. 
Keeping secrets is as old as writing messages. Julius Caesar is said to have encrypted his messages by shifting each letter down the alphabet by a known shift key. An encryption method that changes each letter for another letter or symbol, like this is called a substitution cipher. These are easily broken by frequency analysis. First documented by the ninth century Persian scholar Al Kindi. 
During the second world war, the Nazis used electromechanical machines called enigma and Lorenz. Which were cracked by expert mathematicians working with early computers at the UKs Bletchley park [00:24:00] code, breaking center. Modern encryption uses mathematical methods to ensure that computers cannot brute force the key. Verifying the identity of a user is called authentication. Passwords are the most common means of authentication. But a weak password can easily be brute forced by trying all possible combinations. Passwords can also be guessed or spotted while shoulder surfing. The second layer of protection is added by two factor authentication or 2FA. Typically 2FA requires a code, delivered by text message or generated by a token or app. Or a biometric indicator such as a fingerprint or face recognition. Attacks on the network include distributed denial of service, DDoS, and hacking attempts. Firewalls at the network perimeter will keep out unwanted network, traffic and website should be protected against SQL injection attacks by sanitizing their inputs as we discussed earlier. 

Malicious software or malware, consists of viruses, Trojans, and worms. Antivirus or more accurately. [00:25:00] Anti-malware software can help, but other security measures such as patching firewalls and user training are vital. Social engineering is often called hacking the human and includes phishing pretexting and shoulder surfing. For any company, educating users is important and this should be part of the network security policy. Finally defensive design means designing systems to be secure in the first place. This can include secure network design code reviews, testing, and anticipating misuse. 

As we discussed earlier, robust programming. And security, thus go hand-in-hand and are linked to many of the topics in the final chapter.
 How are we doing for time? 
Alan: I did say I do this in 30 minutes. So I’m going to have to speed this one up. Okay. 
Eleven.
 Issues and impacts. 

Information technology caused a third industrial revolution and analysts are calling the convergence of mobile internet automation and AI the fourth industrial revolution. [00:26:00] With all new technology comes both opportunities and challenges. We face privacy, legal, cultural, environmental, and ethical questions, and many issues span two or more of those categories, such as automation, equality, bias in decision-making and the future of work. Decisions require us to balance competing issues and impacts. 

For example, automation drives down the cost of production and eliminates hazardous occupations, but can cut jobs or worsen inequality. The internet has opened up communications previously impossible, but has created a digital divide between those, with access and those without. Artificial intelligence is revolutionizing manufacturing, healthcare transport and the arts. But it suffers from bias, discrimination and lack of transparency. Cryptocurrencies such as Bitcoin have been criticized for their energy use and electronic waste is a growing ethical, environmental and legal issue. While finite resources needed in smartphones are mined by low paid workers in exploitative practices.

In every question about issues and impacts of technology we must consider all the stakeholders involved, including the creators vendors, shareholders, consumers, and wider society and balance their often competing interests. 

How have I done for time?. 

Wow. That was a whistle-stop tour of the GCSE in computer science. So now you’re ready to sit the exam. Or to teach the subject So let’s revisit our fertile question. 
What is computer science? Have I answered it? Let me know in the comments or on the socials. This has been how to teach computer science, the podcast I’m Alan Harrison. 

If you want to give me feedback or get involved, just go to HTTCS online or check the show notes. I’m also on threads Mastodon an X as mraharrison, remember, if you liked this content, please subscribe. Tell your [00:28:00] friends, buy my books, leave a review of my books on Amazon, or at the very least buy me a coffee. I’m also available for staff training INSET days and student masterclasses see the website for details. Next week, I have a guest, the amazing Andrew Virnuls, who like me sat the old computer studies O-level in the eighties. And worked in IT for decades. So we’ll be catching up and discussing in more detail one of my favorite topics, data representation, 

 I’m off for a cappuccino paid for by our listener mark Weddell. Thanks mark. Really appreciated. If you enjoyed this, why not do the same? Don’t forget to hit subscribe and I’ll see you next week.

You’ve probably heard this week that the CEO of X, formerly known as Twitter, has said he will charge all X users “a small monthly payment”, he claims is needed to combat “vast armies of bots”. This business-model-killing ploy may never come to pass, remember “block is going to be deleted as a feature“? But this latest desperate attempt to shore up a failing company (Musk himself has admitted Twitter has lost around 50% of its ad revenue since he took over, which itself was over 90% of the company’s revenue), might just be the nail in its coffin. Here’s why I hope it is. And even if it’s not, here’s why you should leave and build your following somewhere else (possibly Meta’s Threads?) for your own safety and wellbeing, and before X collapses completely.

The issues

Through our presence on the platform, we are supporting the company and thus tacitly, the values it represents, and those of its owner. Musk has repeatedly shown himself to be an alt-right Trump and Putin supporter, even attending the World Cup Final with Trump’s son-in-law Jared Kushner and the Superbowl with the right-wing media-owning Murdoch family. Musk has allowed literal Nazis back onto Twitter including Andrew Anglin, editor of white-supremacist website The Daily Stormer. Anglin had been banned from Twitter back in 2017 after calling for death to “enemies of the white race” at the rally where an anti-Nazi protestor was murdered by a self-confessed neo-Nazi. Meanwhile, Musk was quick to ban five left-wing journalists including respected Washington Post reporter Drew Harwell, for daring to draw attention to his frequent private jet travels.

Earlier this month, Musk boosted the hashtag #BanTheADL, a campaign against the internationally respected charity fighting antisemitism, the Anti-Defamation League. In a series of tweets such as this one, Musk amplified attacks on not just the ADL but on the American Civil Liberties Union (ACLU) and the Southern Poverty Law Center (SPLC), organisations that exist to fight discrimination and inequality. He has threatened a defamation lawsuit against the ADL and bizarrely blamed them for X’s fall in advertising revenue. Recently Musk has given a platform to America’s chief insurrection supporter and election-denier, alt-right darling Tucker Carlson, after Carlson was fired by Fox for lying about the 2020 election (and being chosen as the fall guy). Carlson and others’ constant lying about the 2020 result contributed to the January 6th 2021 violent attack on the Capitol which resulted in seven deaths, and Carlson continues to lie, in his X-hosted content, about the terrible events of January 6th.

Musk has also gone after the LGBTQ+ community, posting without evidence that the horrific hammer attack on the husband of then-House speaker Nancy Pelosi might have been a “gay lovers’ quarrel”, and in this single tweet both mocked trans people and boosted anti-scientific medical disinformation:

My pronouns are Prosecute/Fauci

Elon Musk on Twitter, 12 Dec 2022

He has spoken repeatedly about the “woke mind virus“, a common trope in the alt-right community that suggests that “being woke” is a socially contagious disease, rather than just, as Kathy Burke suggested, “not being racist, not being homophobic and just calling out bad things”.

In April 2023 Twitter removed a section of T&Cs that specifically protected trans people from “targeted misgendering or deadnaming”, leaving it as the only major platform without specific transphobic abuse protections. And Musk’s release of former Twitter safety chief Yoel Roth’s internal communications, in a document dump Musk named “The Twitter Files”, followed up with deliberate targeted misinformation, has caused Roth to take his family into hiding with police protection, after a barrage of death threats and accusations of “grooming” from homophobic and antisemitic followers of Musk.

Roth was sacked along with almost the entire safety team. Musk has in total fired around 80% of Twitter’s workforce, most of them just before Christmas 2022. The layoffs disproportionately impacted women, Black employees, and employees aged 50 and older. Hard working people with families to feed were given little notice and the legal minimum severance pay (and some not even that). Musk also ordered people working at home to return to the office, a move which discriminates against disabled employees and those with caring responsibilities, not to mention adding an environmental cost. Indeed, Musk tweeted baseless criticism of one particular disabled employee with muscular dystrophy in a tweet exchange that makes for painful reading.

And let’s not forget the rise in misogynistic content, with Musk welcoming back to the platform misogynists-in-chief Donald Trump and Andrew Tate. Musk recently joined Tate and the roster of right-wing outlet GB News in rallying to the defence of Russell Brand who stands accused of multiple counts of rape and sexual assault, although Brand denies the allegations. Violent rhetoric against women has escalated since Musk took over Twitter, with misogynistic accounts rising 69%.

All social media platforms have a duty of care to their users. We must feel reasonably safe interacting on the platform, including from scams, inappropriate content, threats of violence and hate speech. Twitter has sacked almost everyone responsible for this service, causing a rise in all problematic content. And Musk’s decision to change “blue tick” verification to a paid service available to everyone has removed a key safety feature: the ability to detect impersonation, and this change has caused a spike in phishing scams on the platform.

Some changes appear deliberate, perhaps to increase engagement at the cost of safety, and some accidental amid rapidly changing priorities. December 2022 saw the removal of the safety feature known as #ThereIsHelp, which promotes suicide prevention hotlines. We saw above how the T&Cs now no longer protect trans people, and we know about the blue tick fiasco. But a recent BBC investigation goes further and depicts a company “on fire” and “no longer able to protect users from trolling, state-co-ordinated disinformation and child sexual exploitation.”

Academics are leaving the platform, unable to talk meaningfully about the climate crisis, politics, race or gender without inviting a litany of abuse. And recent changes to the privacy policy might actually make you unsafe in the real world, as the company plans to collect “biometric and employment data”, yet is known to release sensitive personal data to authoritarian regimes.

This blog cannot begin to capture the many, many problematic actions taken by the X CEO before and after his purchase of Twitter, but Vanity Fair made an attempt to document Musk’s problematic behaviour back in April 2022. Musk is possibly the worst person to trust with our personal details, online safety and everyday thoughts, and his chaotic “management” of the social media platform makes us all unsafe every day.

The implications

When I use social media (SM) in a personal capacity, that’s my own decision and barely affects anyone else. However we sometimes operate SM accounts on behalf of organisations, and as such we are aligning that organisation, to some extent, with the values of the SM platform. We are driving traffic to the platform, and hence doing two things:

• Adding value to the platform: as users we are the product and our views are being re-sold to advertisers and thus we make money for the company to spend on further problematic activity.
• Driving users to the platform: a platform where we know they are now unsafe, in the absence of a working safety team and the presence of a vast army of white supremacists, transphobes and misogynists, which is unethical.

I don’t want any part in supporting this man’s alt-right agenda, and I don’t wish to be responsible for exposing users to the risk of hateful abuse. So for that reason, X, I’m out.

I’m on Threads, Mastodon and LinkedIn, but mostly active on Threads. I’m well aware that all platforms have their ethical questions, and Threads being a Meta (formerly Facebook) product might raise an eyebrow. I get that, but at least Meta has a working moderation team and is not openly aligning itself to enemy tyrants, attacking people with protected characteristics and deliberately amplifying hate. I hope you will join me on Threads, it’s nice over there. See you soon.

Update 2025: I’m on BlueSky now at @httcs.online

“… and off you go, you have 5 minutes.”

Within 10 seconds the whispers start. “What are we doing?”, “What page are we on?” “Are we copying down from the board”. “I can’t be bothered, want to play noughts and crosses?”

“Right, stop and listen, I’ve just told you about the impact of Robotics on employment, you need to list three industries and explain how they have changed because of robotics. All clear? Good.”

“Sir, do we use the textbooks?”

“No, just from memory and the stimulus on the board (indicates some pictures of robots in factories, agriculture etc.”

“Can we use the internet for research?”

“No, just the stimulus and your memory of what I just told you.”

“Can you tell us again, Sir?”

Sigh. “OK robots are used extensively in car manufacturing……”

This was me about five years ago, before I discovered Teach Like a Champion, and other sources of material about deliberate practice, defined here as…

‘Deliberate practice […] is a highly structured activity, the explicit goal of which is to improve performance. Specific tasks are invented to overcome weaknesses, and performance is carefully monitored to provide cues for ways to improve it further’

Ericsson et al. 1993 quoted in “What is Deliberate Practice” by the Ambition Institute

Teaching a class is an unnatural activity, and novice teachers are often unaware of the highly-specialised skill needed to do it effectively. When I started I was supremely unaware of the importance of routines, cues and systems. I held a misconception that all failures to follow instruction were down to poor student choices: in effect I blamed the students for my lessons falling apart. I failed to recognise the importance of my practice in ensuring the correct choices were easier than the poor ones.

Specifically, in the lesson above, I had failed to do several things:

1. Ensure everyone is paying attention to the instructions (and throughout the explanation, keep looking and be seen looking and correct any inattention in the least invasive way possible)
2. Clearly articulate the means of participation, that they are to write in their books, using the stimulus on the board only, no internet.
3. Check for understanding of the task, perhaps by asking a student to report back what the task is, ensuring the class’s attention is on the conversation between me and the student speaking.
4. Signal the start of the task and remain looking, using non-directed correction and moving towards directed e.g. “That’s most of you working now, just 3 more to start… OK 1 left now, please get started… OK Robert can you get started please…. Great stuff, you have 5 minutes working in silence.”
5. Walk the room, checking for misconceptions and misunderstandings as they work.

I do all of the above now, and my transitions are far more effective, the students make more progress and the lessons are calmer and more purposeful.

How did this come about, my improved effectiveness as a teacher? CPD and self-study of deliberate practice techniques. I read blogs and books, and eventually stumbled onto Teach Like a Champion (TLAC) almost by accident, but by 2020 my school had started to promote the book among other sources for teachers to self-study, and by 2021 had incorporated parts of it into our usual staff CPD. Once a fortnight the training would be called “Deliberate Practice CPD” and we would discuss a TLAC technique and take it back to our departments. This training was positively received by most staff who recognised that “sweating the small stuff” usually paid off in the form of more productive lessons. The bulleted list above is from “Brighten Lines”, a TLAC technique described here in full by Lee Donaghy. It’s fair to say that this technique alone improved my practice so much that it was worth the cover price of the book on its own.

If you’re reading this thinking “all of that’s obvious, though, I do all of that anyway”, then you are suffering the “curse of knowledge”, which I talked about here, and described as the failure to see a domain as a novice does, and to thus understand their needs. There is a parallel here with driving: we can probably all learn to drive without an instructor, just by repeatedly practicing. We would probably crash a lot, but eventually we would get there. Likewise, teachers have traditionally discovered what works in various unstructured and accidental ways, but many experienced teachers forget how hard teaching was in their early days. A good professional development curriculum is therefore a good thing, and books, blogs and videos can be part of that.

Critics of TLAC I’ve read online recently have made some interesting assertions, some of which I want to address now…

SLANT IS OPPRESSIVE, EVEN FASCIST

The recent Twitter conversation around SLANT and the discussion between Tom Rogers and Phil Beadle was fascinating. Much has been said about this by more articulate people than me, and I don’t want to re-ignite the arguments. But what struck me most was this response from TLAC author Doug Lemov, clarifying what he actually believes, regarding the best way to direct students’ attention where it is needed. He explains that he re-named the technique formerly known as SLANT to “Habits of Attention”, and the acronym to STAR:

• Sit up to look interested and stay engaged.
• Track the speaker to show other people their ideas matter.
• Appreciate your classmates’ ideas by nodding, smiling, and so on when they speak.
• Rephrase the words of the person who spoke before you so they know you were listening.

What seemed to me, to be missing from the debate around SLANT was that “Track the speaker” meant track whoever is speaking, including the student contributing to the class discussion. Note also the following two bullet points which clarify the rather strange “Nod” direction in the previous version: the point of SLANT/STAR was always to encourage listeners, both teacher and student, to appreciate and value everyone’s contribution in the classroom. This is a far cry from the recent mischaracterisations of SLANT as a form of oppressive teacher control.

While we’re on SLANT, I note that “S” for “Sit up” does not say “Sit bolt upright” as Phil Beadle claims in the interview above, nor is that implied anywhere in TLAC or in any CPD I have attended. I simply get “eyes on me” and deal with any students turning away as non-invasively as possible, but I’ve seen no evidence to support schools that use TLAC insisting on “bolt upright” posture. Indeed, here is Doug Lemov clarifying just that in his recent blog:

An additional challenge can be that managing attention behaviors can prove successful enough that it can lead to a spread in managing behaviors less clearly tied to attention: hands folded on the desk; back flat against the chair, and so forth. To be clear, these behaviors are not something I’ve discussed in Teach Like a Champion (my emphasis), but I have certainly seen classrooms where they are reinforced in a counterproductive way and sometimes in the belief that this book endorses them.  Reminding students who are at risk of becoming distracted—or who are sending unsupportive messages to peers—to Track or SLANT can be useful; telling students to keep their feet flat on the floor or interrupting them when they are productively engaged in a discussion to tell them to fold their hands on the desk is not. What if they want to take notes?

TRACKING IN CLASSROOMS: WHAT I REALLY THINK (AND WROTE) – Doug Lemov 4th
May 2023

Lemov could hardly have made it more clear that “bolt upright” is not suggested by any of the TLAC techniques.

“Habits of Attention” (the technique formerly known as SLANT/STAR), “Brightening Lines” and the other 47 techniques are a goldmine of ideas for improving classroom practice, and if implemented thoughtfully can help transform a classroom from a disorganised place of unrest and confusion to a thoughtful community of learning.

“Habits of Attention” signal that our words (of both teacher and student) are important because they convey our ideas, and everyone’s ideas are worthy of our attention.

“Brighten Lines” ensures that everyone understands what is expected of them, reduces confusion and increases the opportunities for learning and making good progress.

TLAC is “all or nothing”, you’re not doing TLAC if you do SLANT without the N, for example.

This is an odd criticism. TLAC is described on the publisher’s website thus: “Teach Like a Champion provides educators with a set of techniques, a shared vocabulary, and a framework for practice”. Nowhere does the author suggest that it’s “all or nothing”. In that same Lemov blog mentioned above, he says this:

In this acronym [STAR] you can see I’ve added details about purpose. Nodding is included in the “appreciate” step to emphasize the importance of appreciating your classmates. That said, you might replace the “Appreciate” A with an A called “Active listening” (to help you focus and show that you value your classmates). “Sit up” includes a purpose as well, so you look interested and engaged. You’ll also notice that I’ve brought in an idea from the Habits of Discussion technique, “rephrasing,” but you could drop it if you wanted, perhaps replacing it with something else. Again, I am describing options here because the behaviors described in any acronym (and the expectations) should be carefully thought through at the school or classroom level. My version of STAR may be helpful, but the adaptations you make to it will make it even better.

TRACKING IN CLASSROOMS: WHAT I REALLY THINK (AND WROTE) – Doug Lemov 4th
May 2023

So from the author’s pen: TLAC is a helpful guide to what works elsewhere, to be implemented and adapted by thoughtful, experienced practitioners and novices with expert guidance in their own settings. The “TLAC is all or nothing” criticism is just a “No True Scotsman” fallacy.

TRACK THE SPEAKER AND COLD CALLING ARE CHALLENGING FOR VULNERABLE STUDENTS

I have taught a great number of vulnerable students in my time. Oliver (not his real name) was in my form a few years ago. Oliver was autistic and found eye-contact hard, so I didn’t insist on it, just that he wasn’t paying attention to anything else such as a book or computer. He also found answering in class challenging, and responding well to cold-calling near-impossible, so I worked with him on how to make a reasonable adjustment. I would go up to him discreetly during a task and say “if I ask a question about this topic in 2 minutes can you get an answer ready?” If he was willing then I would ask and he would answer, and over time his confidence grew. Oliver’s gratitude-filled, handmade good luck card to me when I left that school remains one of the best gifts I’ve ever received.

Daniel has ADHD and shouts out or makes other involuntary noises. I am understanding about this, so if I ask a “hands-up” question and he shouts out without putting his hand up, or I cold-call someone else and he answers, or simply interrupts someone else with an outburst, I’ll accept this in good grace, and the class naturally understands that I’m making a reasonable adjustment for Daniel. I use TLAC to maximise learning, but crucially, I’m not a monster!

GOOD TEACHERS ALREADY DO EVERYTHING IN TLAC

Great! I’m glad for you, but if this is your position then please recognise you got here through a long and painful journey of learning what works and what doesn’t. You will have taken a few steps back at times, and eventually arrived at a practice that works well for you. Not everyone is there yet, so I welcome the opportunity that TLAC presents to novice and improving teachers: the chance to try techniques that many others have had great success with, well-explained with helped videos and lots of valuable background including the research that is behind it.

A related claim that pops up often, including recently on Twitter, is that TLAC is claiming “credit for inventing pedagogy”. This is also a strawman, as Lemov points out that TLAC is a collection of good practice, not brand new ideas. Here’s Lemov in his own words again…

How do you answer staff who claim TLaC is just common sense? “I know how to pass out books!” is a quote I have heard.

The comment doesn’t bother me.  Honestly, if it is “common sense” to a lot of teachers that the ideas in the book are effective and can help you make your classroom work, then I am happy.  If I have merely collected a lot of things that teachers know work and if teachers have a place to go where they can find lots those solutions, well I’m really happy with that.  If you know some of the ideas already, great.  Other people may not.  There may be others that can help you.  Or studying what you already do a bit of could help you be even sharper. I guess for some people “useful” is faint praise.  They want to be brilliant or innovative or original.  In the end I am more interested in what’s effective than what’s new or “innovative” or makes me look like I thought all this stuff up.  I didn’t. that’s what makes it valuable.   

Stephen Tierney interviewing Doug Lemov in his Leading Learner blog, 2016.

COLD-CALLING IS JUST “NO HANDS UP QUESTIONING”, WHY THE AWKWARD NAME?

Perhaps you do the techniques but hate the acronyms and “jargon-y” names for the techniques? Teaching practice is a domain of specialist knowledge just like the domains we teach (Computing in my case, or maths, or history). We usually call it pedagogy, but whatever you call it: learning to teach, discussing what works and what doesn’t work; communicating this knowledge to others is difficult without shared names for things.

“Cold-calling” is a memorable, 3-syllable name for a specific technique described in TLAC. At it’s heart is asking a question and then choosing students to respond by name, rather than asking for raised hands and asking someone who has their hand up. (The reason is ratio, read more here, but I don’t have time to discuss that today.)

TLAC techniques all have short, memorable names such that practitioners can discuss techniques easily and build CPD around them, and everyone knows what is being discussed, and can look in the book or online for further information by searching the term. If you don’t like the term, use another one. If you must (as one critic recently said on Twitter) you can call it “asking kids who haven’t got their hand up” if that is more palatable to you. But I leave as an exercise for the reader, which phrase is clearer, easier to communicate, and more memorable.

Complex concepts in every domain of knowledge must be named. Jargon is just another word for technical terminology, and teaching is already rife with jargon, which is not inherently a bad thing, it speeds up conversations between experts. Here are some teaching jargon phrases off the top of my head: working memory, restorative justice, fixed-term exclusion, MFL, DBS, walking-talking mock, SpLD, Safeguarding, inquiry learning, time-out pass, reduced timetable, think-pair-share…

If you don’t like the terms, don’t use them, but don’t expect others to immediately know what you mean if you’re using an imprecise phrase instead of a well-established “jargon” phrase.

Finally, on the name of the book… I myself wrote a book recently, on teaching computing, you may have heard of it, I called it “How to Teach Computer Science“. It wasn’t always going to be called that, working titles were “Computer Science Teaching Handbook” and “Computer Science Teaching: The Fine Manual” (because I wanted to tell people to RTFM). I settled on HTTCS after a conversation with my copy-editor, who liked the idea of a “How To..” title. Is it a bit arrogant? Definitely, but I would like to sell a few copies, so a snappy, positive title is a good idea. One of the oddest criticisms of TLAC I hear is the “title is arrogant” or similar, and “Lemov just has a product to sell”. Yes, it’s designed to sell. As an author I’d like to get paid for my work, I’m sure Lemov feels the same. If you disagree with TLAC, why not broaden the debate with a book of your own, rather than arguing against the author’s right to get paid for his work?

TLAC helped me become a better teacher. It wasn’t the only way this could have happened, but I’m glad TLAC exists because without it I might not have made as much progress quite as quickly. The techniques help me achieve and maintain a warm, purposeful atmosphere and maximise attention and thought on that which is important: the learning. But as Lemov didn’t quite say (but probably would): you do you.