Tom Rocks Maths S02 E11

A special edition of Tom Rocks Maths on Oxide Radio with music inspired by Tom’s recent visit to Slam Dunk Festival. We’ve also got Pokemon and drinking games, a mind-bending Einstein Puzzle, and news of Tom’s antics running around the streets of Oxford in his underwear… This is maths, but not as you know it.

Maths and the Media

Arriving at St John’s in 2008 to begin my study of mathematics, I was certain that within 4 years I would be working in the city as an actuary or an investment banker. Whilst I loved my subject, I saw it as means to obtain a good degree that would set me up for a career in finance. I’m not sure I could have been more wrong…


My current journey began towards the end of my second year, where I found myself enjoying the course so much that I wanted to continue to do so for as long as possible. This led me to research PhD programmes in the UK and the US, and I was fortunate enough to be offered a place to study Applied Maths at the University of Cambridge in 2012. During my time at Oxford, I found myself straying further and further into the territory of applied maths, culminating in a fourth-year course in fluid mechanics – the study of how fluids such as water, air and ice move around. This ultimately led to my PhD topic at Cambridge: where does river water go when it enters the ocean? (If you’re interested to find out more I’ve written a series of articles here explaining my thesis in simple terms.)

As part of my PhD I conducted experiments, worked on equations and even took part in a research cruise to the Southern Ocean. It was on my return from 6 weeks at sea that I had my first taste of the media industry via a 2-month internship with the Naked Scientists. I would spend each day searching out the most interesting breaking science research, before arranging an interview with the author for BBC radio. It was great fun and I learnt so much in so many different fields that I was instantly hooked. Upon completion of my PhD I went to work with the Naked Scientists full time creating a series of maths videos looking at everything from beehives and surfing, to artwork and criminals. You can watch a short trailer for the Naked Maths series below.

My work with the BBC and the media in general ultimately led me to my current position as a Mathematics Tutor at three Oxford colleges: St John’s, St Hugh’s and St Edmund Hall. This may not sound like the media industry, but the flexibility of the position has allowed me to work on several projects, including launching my website and my YouTube channel @tomrocksmaths where I am currently running two ongoing series. In the first, Equations Stripped, I strip back the most important equations in maths layer-by-layer; and for the second series in partnership with the website I Love Mathematics, I answer the questions sent in and voted for by students and maths-enthusiasts across the world.

Alongside my online videos, I am also writing a book discussing the maths of Pokémon – Pokémaths – and have a weekly show with BBC radio called ‘Funbers’ where I tell you the fun facts about numbers that you didn’t realise you’ve secretly always wanted to know. I have also recently presented at conferences in the US and India and hold regular talks at schools and universities, including for the Oxford Invariants and the Maths in Action series at Warwick University where I faced my biggest audience yet of 1200.


Looking back at my time at St John’s, I never would have imagined a career in the media industry lay before me, but the skills, experience and relationships that I formed there have undoubtedly helped to guide me along this path. I think it just goes to show that Maths is possibly the most universal of all subjects and really can lead to a career in any industry.

You can follow Tom on Twitter, Facebook and Instagram @tomrocksmaths for the latest updates.

Blueprint Interview

Interview with the University of Oxford’s Blueprint magazine about my mission to popularise maths and my outreach work with the St John’s Inspire Programme. The full interview with Blueprint’s Shaunna Latchman can be found in the online magazine here.

While some avoid arithmetic at all costs, Tom fully immerses himself daily teaching maths to the first and second year undergraduate students at St Hugh’s College. He also arranges activities for St John’s College as the Access and Outreach Associate for Science, Technology, Engineering and Maths (STEM) for the Inspire programme. Another activity is planning and filming content for his own outreach programme – Tom Rocks Maths.

‘It was the subject that felt most natural to me’, explains Tom, who first realised his love for numbers aged seven when his class had been set ten long multiplication questions. He raced through the whole book. However it wasn’t until he received ten A*s in his GCSEs that he began considering an Oxbridge education. ‘Academically there isn’t much of a difference [between Oxford and Cambridge]’ Tom comments, ‘but Oxford felt more like home.’

Later, after completing his PhD in Applied Maths at Cambridge, he was offered an internship with public engagement team, the Naked Scientists. The group strip back science to help make a complicated theory easy to digest. Weekly podcasts are broadcasted through BBC Radio 5 Live and ABC Australia, where audiences reach up to one million listeners a week.

Tom saw an opportunity to bring his appreciation for maths to the masses, but he wanted to do it with a twist. Eager to move away from the stereotypes of maths being a serious subject taught by older men in tweed jackets, he thought ‘what is the best way to make maths less serious? Doing it in my underwear!’ And so, the Naked Mathematician was born.

Since joining St Hugh’s, Tom continues to break down day-to-day activities on his YouTube channel to prove that maths is an integral part of everything we do.


His passion for engagement doesn’t end there. The Inspire programme, part of the Link Colleges initiative, is a series of events, visits, workshops and online contact for pupils in years 9 to 13. Tom works with the non-selective state schools in the London boroughs of Harrow and Ealing.

The Link Colleges programme simplifies communication between UK schools and the University. Every school in the country is linked with an Oxford college, with the hope that this connection will encourage students to explore the possibility of attending university.

‘The aim is to have sustained contact with the same group of students over five years,’ says Tom. ‘There are still students who haven’t thought about university, or maybe it’s not the norm in their family or area to attend university. So, we explain what it is, how it works and the positives and negatives. We want to inform and inspire them.’

Tom is responsible for arranging all STEM events across the year for 60 students in each year group. He calls on the expertise of his colleagues at Oxford as well as encouraging a partnership with the University of Cambridge and several universities in London. ‘The syllabus includes various topics such as the science of food and using maths to improve diet.’

During Tom’s famed Maths vs Sport talk, students are encouraged to participate in an on-stage penalty shootout – but only after learning about the mathematical makeup behind such a pivotal moment in a football game, of course.

Tom believes maths is made more accessible by relating it the world around us. He encourages his students to question things, like why bees make hexagonal shapes in their hives and how many Pikachus it takes to light up a lightbulb.

Whether visiting schools up and down the country to deliver talks, recording the weekly dose of Funbers for BBC radio – fun facts about numbers that we didn’t realise we secretly wanted to know – or in front of his class of students, Tom is certainly making waves in the world of maths.

Pokémaths: how many daily calories does a Charizard need?

If you’re like me and you’ve always wished that Pokémon were real, no doubt you’ve dreamt of having one of your very own as a pet. I don’t really like pets, they look like a lot of effort and stop you doing fun things like going on holiday, but if I could have a Charizard living in my backyard, well now that’s a whole new ball game…

Let’s suppose that is exactly the case – you have a pet Charizard living in your garden. For those of you unfamiliar with Charizard, think fire-breathing dragon and you’ve pretty much nailed it. As with all pets (I assume) you have to think about how much food to feed them, or more specifically how many calories does your pet need in order to survive. An average sized dog needs around 800 calories per day, whilst cats are a little smaller and so only need about 300. So as with most things in life, size matters, which brings us back to our fire-breathing dragon…


Game of Thrones fans a word of warning: dragons aren’t all as big as the ones belonging to Daenerys. The main one Drogon is often pictured as being at least ten metres tall and weighing as much as a small house, but that is not the case with Charizard. Pokémon tend to be much smaller than you might think and according to the official Pokédex an average Charizard stands at 1.7 metres tall and weighs in at 90 kilograms. I don’t know if this was on purpose but that is almost exactly the same as the average height and weight for a male human. The recommended daily intake of calories for such a male is 2500 per day, which gives us a good starting point for our pet Charizard. But, we also need to think about fire.


A fire needs three key ingredients to burn successfully: fuel, heat and oxygen (see fire triangle above). If any of the three are missing, then the fire will go out (this is why it’s called the ‘fire triangle’, as without one of its sides a triangle is no longer a shape). Charizard has a flame burning on its tail that is said to grow hotter with increased battle experience. We can safely assume that the tail flame is getting its supply of oxygen from the atmosphere, which contains 21% of the gas. The majority (78%) of the air is nitrogen plus a few other bits and pieces such as unreactive argon (0.93%) and the big baddie carbon dioxide at what seems a measly 0.04%, but is still enough to heat up our planet.

That’s the oxygen taken care of, now what about the heat? Well Charizard is probably quite a warm creature, especially with all of this fire-breathing going on, so it’s probably safe to say that the heat comes from its body. That just leaves the fuel – it has to burn something to be able to produce fire. The most likely culprit is to burn its food, i.e. calories. A calorie by definition is approximately the amount of energy required to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere. Just to be super confusing, the calories we talk about with food are actually kilogram calories and are equal to 1000 of the little ones. This is why calorie content on food labels is often given in both units of kcal and cal, though not always (again just to be super confusing).

If we assume that the flame on Charizard’s tail burns similar to a lab Bunsen burner (a reasonable assumption I feel), then it will generate a power of around 1 kilowatt. Therefore, in order to burn for 24 hours, it requires 24 kilowatt hours of energy – a kilowatt hour is just the amount of power in kilowatts times the length of time it is produced for in hours. We know that 1 food calorie is equal to 0.00162 kilowatt hours (thanks Wikipedia) and so the number of calories required to power the flame on the tail of a Charizard is


Just to clarify this is the big food-based calorie, which means a LOT of food for your fire-breathing pet dragon. Even with a conservative estimate, a Charizard is going to need to eat as much food as 6 fully grown men to be able to keep it active for just one day. Maybe I was right and pets aren’t such a good idea after all – especially the ones that breathe fire…


All of the material in the Pokemaths series can be found here.

Pokémaths: how many Pikachus does it take to power a light bulb?

The mascot of the Pokémon world and probably the most famous of all the Pokémon: Pikachu. It’s pretty much just a short, chubby rodent with two red circles on its cheeks that it apparently uses to store electricity. So the obvious question to ask here then is how many Pikachus would it take to power a lightbulb?

The official Pokédex tells us that Pikachu is able to ‘release electric discharges of varying intensity’ and is also known to ‘build up energy in its glands that needs to be discharged to avoid complications’. Quite what these ‘complications’ might be I’m not sure – suggestions on a postcard. The Pokédex also says that the tail of a Pikachu plays an important role as it acts as a grounding rod to prevent the creature from electrifying itself and also allows one Pikachu to recharge another one that’s running low on juice. Another fun fact about Pikachu’s tail is that a female will have a v-shaped notch at the end which is not present on males. Next time you’re out Pikachu hunting, now you know.

When a Pikachu uses its signature move, thunderbolt, it releases 100,000 volts of electricity. You might think that this would be enough to kill you, never mind just power a lightbulb and you wouldn’t be wrong, but there’s a little more to it than that. When someone dies from electrocution, it isn’t the voltage that kills them, it’s the current. If a current of just 7 milliamps reaches your heart for around 3 seconds its lights out. The current is tiny, but it disrupts the hearts natural rhythm causing it to stop. You can of course be electrocuted and live to tell the tale, but this means that you were very lucky in that the path that the electricity chose to take through your body must have avoided your heart. In general, electricity will flow along the path of least resistance, as with most things in nature it’s lazy and so takes the path that is the easiest.

I’ve now mentioned three terms, which means a good old fashioned physics formula triangle. The particular one we want here is Ohm’s Law:


The resistance of your body is around 100,000 ohms, which means thunderbolt generates a current of 1 amp that will flow through your body. In other words, if it hits your heart you’re toast.

Now onto lightbulbs. They come in all sorts of different shapes and sizes, and different amounts of wattage or power. The standard one is 60 watts and that’s the one we’re considering here. None of these fancy energy saving bulbs that start off really dim so that you can’t see a thing and gradually build up in brightness… (don’t get me started on them). The key bit of physics that we need relates power (in watts) to Ohm’s Law above and states:


For a 60 watt light bulb attached to the UK mains supply of 230 volts, this generates a current of 0.26 amps. If we were to connect the bulb up to a Pikachu using thunderbolt the current decreases hugely to only 0.0006 amps. The light bulb will still work but the current will just be very small. This means only a small wire is required and also has the added benefit of reducing the chance of electrocution… However, 0.0006 amps is still enough to kill you if it hits your heart, so be careful next time when you’re hooking up your lightbulb to a Pikachu!


All of the material in the Pokemaths series can be found here.

Pokémon: the numbers

I love maths (as most of you will know by now) and I also love Pokémon (as some of you will also know), so I’ve decided to combine the two into a new project called Pokémaths. I’ll be doing the maths to answer such questions as: how many Pikachus does it take to power a lightbulb? How many calories would a Charizard need to eat every day to survive? And would Squirtle actually float?

But before I get to these important questions, let’s first talk numbers, specifically numbers of Pokémon. There are a LOT of Pokémon these days – 802 to be exact – and where better than to start with the original and best: Red and Blue. I’m a 90’s kid (though technically I was born in the 80’s which does mean Calvin Harris has love for me) and so I spent far too much of my childhood playing the original Pokémon – I was Red in case you asked. This first generation had 150 Pokémon for you to catch (or was it 151… did anyone ever find Mew?) and they ranged from everyone’s favourite little yellow mouse Pikachu to a big pink blob called Ditto.

The second instalment came with Pokémon Silver and Gold which brought with them exactly 100 new Pokémon. Most of them were still animal based, but there are a few more original ones… including some numbers! The Pokémon Unown (below) could take the form of any of the 26 letters of the alphabet, a question mark or an exclamation mark. So whilst not quite being a number itself, you can certainly collect a few of them together in your team to spell out O-N-E or T-W-O or T-H-R-E-E or F-O-U-R or…. I think you get the picture.


Generation three meant another 134 new Pokémon, this time as part of the games Ruby and Sapphire, taking the total number to 386. Judging by the naming convention the Pokémon Company clearly put all of their creative effort into creating new Pokémon rather than naming the games… Some of my favourite Pokémon appeared in this generation – take Ludicolo for example, he’s basically a frog wearing a poncho and a sombrero. And don’t forget about Porygon-Z, the fully-evolved form of Porygon, who was one of the original 150. Porygon is great because it’s basically a 3D maths shape and also a play-on-words of polygon, which means any flat shape with at least three straight sides and angles.

Next up were Pokémon Diamond and Pearl – the first step away from colours – hooray! Though they will be back shortly. This generation introduced another 107 new Pokémon and they start to get really freaky… Take Drifloon for example. It’s a balloon. With a face. And a cloud for hair, obviously.


For generation five we go back to colours, naturally, with Pokémon Black and White. These games were the first since the original ones to introduce a full 150 brand new Pokémon, plus 6 bonus special edition ones. With such pressure comes inspiration – or at least I assume that was the plan. A Pokémon that’s a pile of garbage called Trubbish? Or a candle called Litwick? Really? Let’s just make all inanimate objects into Pokémon… oh, wait they did that. Generation six brought us Pokémon X and Y (another step away from colours, well done Nintendo) and with them came the Pokémon Klefki. This is a set of keys with a face. Its either genius or madness, you decide…


Generation six gave us 72 new Pokémon, taking the total up to a whacking great 721. Creating that many original characters is quite the feat, even if we have ice cream cones with faces… Vanillite I’m looking at you. The final installation came late last year with another non-colour-named set: Pokémon Sun and Moon. They were released to mark 20 years since the original games – wow, I’m old. The latest instalment brings us 81 new Pokémon giving a final total of 802. That’s 802 unique, original, entirely fictional characters. It’s seriously impressive (despite my complaints).

My plan with Pokémaths is to pick the most interesting and exciting Pokémon (obviously there a lot) and do some maths with them. It will combine my two favourite things and hopefully show you that maths can be used for absolutely ANYTHING. It’ll be fun too – after all who doesn’t want to know how much weight a Machamp can bench press?


All of the material in the Pokemaths series can be found here.

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