What is physics?

At the start of the school year when I first meet my GCSE students, I ask them to write a letter introducing themselves. I provide some prompt questions, and show how I would answer them about myself to give them an idea of what I’m after. This year I shared that I am Belgian and that I speak French, I have a fluffy ginger cat called Benjie, I play quite a few musical instruments (and will be writing physics revision songs), I love roller skating (and that roller skating is full of physics) and I care a great deal about nature and sustainability. I explain the purpose of this exercise: for me to understand their goals, motivations, challenges and interests so that I can teach them as effectively as I can.

Some students write a couple of sentences that give me little to go on. I now know that they have a pet dog and they like football. Others will offer me pages of passionate prose, full of perceptive insights and radical honesty. I’ve had a number of students come out to me on the page.

There’s one question I always ask. Do you have any questions about physics? The answers I get here are some of the most revealing.

Among my Y11 students this year the most common questions were: what is physics, why do we have to study physics in school (the ‘have to’ makes my heart sink), what jobs can studying physics help with, who invented physics and who was the first physicist?

My students have spent eleven years of their life in school, and the last two studying physics as a separate subject. And yet at no point have they explicitly been taught what physics is, why they should study it and how it might help them in the future.

This is not unusual.

With a packed curriculum, many schools don’t actively make space for this kind of big picture thinking. And yet, it is essential. In order to be motivated to study — or indeed to do anything in life — students would benefit immensely from understanding what it actually is they are studying, not to mention why it’s worthwhile.

And so I spend a lesson answering their questions.

Physics is about matter

I’m seven and a half. We’ve just watched Jurassic Park for the first time — the scary cushion alternately clutched to my chest and shielding me from the velociraptors. I am far too excited to go to bed. “But how big is that?” I demand to understand.

My Dad’s face screws up. His eyes dart around, and his gaze suddenly settles on the window of our third-floor flat. He springs up with a hint of a smile and rushes to the balcony. “Come here!” he calls out. I gingerly approach. There could be a velociraptor out there for all I know.

Opening the door, letting in the fresh evening air, he raises a hand up to his head height with his arm held out over the edge of the balcony. “Up to here. I reckon that T. rex would reach from the ground up to here.”

I stand well back and shudder. With my seven-year old imagination, it’s all a bit too real. I shuffle back indoors and rest my hands on the table. Its solidity feels reassuring. I squeeze the hard surface and get struck by a new question.

“Hey Dad, what’s the table made of? I mean the wood, deep inside?”

He’s a little surprised. But only a little. He grabs some paper and a pencil, tells me about atoms, draws a sketch. I nod (wisely, I like to think).

“And what are atoms made of?” He raises an eyebrow. “Well, inside the nucleus there’s… umm… Protons and neutrons!” He adds to his sketch. “And electrons… well, I think they’re just made of electrons?”

Without missing a beat, my next question, “What are protons and neutrons made of?”

Dad pauses.

This is unusual. My eyes widen, I wait intently.

“I think… they’re made of even smaller particles called quarks. But there are different types and I don’t know much about them.” He frowns, the quarks are added to his sketch.

I gaze in wonder at the little circles with ‘q’ scribbled on them.

This is the first time Dad, a scientist — a palaeontologist, not a physicist — isn’t able to answer one of my questions. In the space of a couple of seconds, everything feels different. The nature of my reality has subtly shifted.

And I cannot wait to find out more about quarks.

Physics is about energy

My hand shoots up again. I’m 13. What is it, the seventh time this lesson? My physics teacher acts as if he hasn’t seen it. Once he’s finished his explanation and set us some practice questions, he comes over to my desk. “Go on, Carole.”

“But what actually is energy?”

He gently chuckles. “Well… that’s actually rather hard to explain. I can recommend a good book that… well, it won’t really explain it, but it’ll give you a good idea.”

I read the book in one sitting. An analogy involving toy blocks makes me pause and slowly nod, as the concept of energy begins to form in my mind.

I don’t know yet that I have ADHD, that my brain thrives on novelty and learning and makes me, among other things, endlessly curious. But I know myself well enough to recognise that the sparks of excitement that fly in my mind when my questions can’t be answered are like no other.

And that this only happens when I think about physics.

Physics is about people

I grow to love equations, to understand them as relationships between variables and an insight into the fundamental workings of our world. A peek under the bonnet of the universe.

But it doesn’t escape my notice that they are all named after dead white men. Newton’s laws, Ohm’s law, Einstein’s principle of relativity. Those without a name attached are given no history or context when we’re taught about them. Just unattributed ciphers. I wonder where the constant acceleration equations come from. Who first thought of momentum.

During my thirteen years at school I was taught about just two physicists who were women: Marie Curie and Rosalind Franklin. One died a painful death caused by her radioactive experiments. The other’s research was used without her consent, and she wasn’t given credit when the men who took her work won a Nobel prize. On the rare occasion when women physicists are represented in the media it is still a source of great excitement to me. When I was 15, I stayed up late with my grandparents to watch a documentary about Jocelyn Bell Burnell, and I’ve always avidly read news stories about women physicists in New Scientist.

In my first year of teaching, fresh out of university, I was determined to do things differently. Before teaching my first Y11 class about forces, I did some digging. What I discovered transformed the way I think about physics and shaped the way I have taught physics from that day forward.

Newton… well… it turns out that it wasn’t Newton who came up with all those laws.

There are a number of contenders for the title of ‘First Physicist’. Let’s give them each a chance to take to the stage and make their case…

Imagine, for a moment, Isaac Newton standing on a stage. He proudly holds a copy of Principia, his famous book on the laws of classical mechanics, the branch of physics relating to motion. Newton’s neat long curls and velvet coat reflect his high status in society. He is the president of the Royal Society and he’s been knighted for his services to science. Few scientists would dare to disagree with him. He addresses the audience with confidence. “Just ask google, and you will see that I am the first physicist.”

“Ahem.” Galileo Galilei, telescope under one arm and cannonballs at his feet, appears and raises an unimpressed eyebrow at Newton. “That first law of yours, it looks quite a lot like my law of impetus.”

Newton, surprised to see someone who died a year before he was born challenging him so impertinently, begins to trip over, lost for his words. “Ah, yes, well, I was an avid reader of your work, and you see, I was very much inspired by you.”

“Speaking of which…” This time it’s Galileo’s turn to be taken by surprise. Ibn Sīnā, born in 980 AD in present-day Uzbekistan, taps him on the shoulder and holds up his own book. “Have you ever read this? You westerners often forget about the work we did during the Golden Islamic Age.”

Galileo reddens. “Ibn Sīnā, old chap! What an honour to meet you! I do remember reading about your ideas in someone else’s book, now you mention it.”

“You all seem to be forgetting something.” A shadowy figure speaks from behind a curtain. “Physics isn’t just about knowledge and ideas. It’s also about how we do physics — how we find out about those ideas.” A figure steps into the stage light. “It was I, Thales of Miletus, who dared to challenge philosophers like Aristotle. He just sat about and came up with ideas — mostly wrong ones. I made the case for experiment, for testing our ideas. That was around a thousand years before you, Newton. Without my insight, physics would never have existed!”

Thales drops the mic.

A door slams open at the back. ‘Like a Girl’ by Lizzo blasts out of the speakers, banners unfurl from the ceiling. “We need diversity in physics.” “Women and non-binary physicists exist.” “Recognise women’s work.” A long parade of women march in, chanting in unison “What about us?” They take to the stage and take turns at the mic.

“We’ve been carrying out our own experiments, and we’ve helped our brothers, our colleagues and our lovers to develop their ideas and carry out their investigations. But for centuries our contributions were minimised or ignored completely. Until recently we weren’t even allowed to study physics.”

“I had to pretend to be a man!”

“I had to do my work in a windowless basement, and they wouldn’t even pay me!”

Emilie du Châtelet storms on the stage, “Oi, Newton! I’m the one who translated your famously dense and difficult-to-read book into French. I made it more readable, I added explanations and — by the way — some equations that were missing. It’s thanks to me that people can even understand your ideas!” Newton blushes and looks awkwardly away.

Lise Meitner slowly steps forward. “I researched the splitting of atomic nuclei, and was the first person to explain fission. Thanks to my work we now have nuclear power stations. I had to flee Germany in 1938 – I’m Jewish — and my colleague took credit for my work. He won a Nobel prize for my ideas.”

“That happened to me!”

“And me!”

She hands Katherine Johnson the mic. “It was thanks to me and the work of my Black women colleagues that the first person was able to orbit the Earth. We faced sexism and relentless racism while we paved the way for the Moon landings. But our story was unknown to most people… until they made that film about us just a few years ago!” Wild cheers and applause make way for a new chant:

“We won’t stay hidden anymore! We won’t stay hidden anymore!” We won’t stay hidden anymore!””

The chant subsides and makes way for reverent silence as Jocelyn Bell-Burnell, wearing a scarf decorated with stars, planets and the pulsars she discovered, takes the mic. “A few years ago I won a £2.3 million prize for my research. I faced many challenges as a woman physicist, and I want to make the future brighter for those who follow me. I used my prize money to set up the Bell Burnell Graduate Scholarship fund. If you come from a background that has traditionally been underrepresented in physics, and you want to become a physics researcher, apply to my fund. I want to pay for your studies.”

Independent Women by Destiny’s Child begins to play as everyone in the theatre explodes into dance and whoops for joy.

Physics is about you

Back to my classroom.

I try to give my students opportunities to learn about some of the wonderful characters who have contributed to our knowledge of physics. I also share examples of a range of careers in physics and using physics, so they can see where studying physics can lead them.

But physics isn’t only useful for future physicists. Those of us who want to do DIY or be carpenters need to understand forces and how materials behave under stress. If you want to be a beautician you ought to understand UV radiation. And if you want to be a business owner it helps to have a basic understanding of safety around electricity. Everyone wants to know how to keep their home warm, how to understand their gas and electricity bills, and make the best choice out of the different tariffs available. When it comes to voting in elections, you need to understand the advantages and disadvantages of different renewable and non-renewable energy sources. You also want the politicians making decisions that affect you to have some understanding of physics to inform their policies.

Learning about space may not help with your job, but how do you feel looking up at the stars and Moon at night? Does it add meaning to your life to understand something of what you’re gazing at? Does it blow your mind to recognise a planet and be reminded that you too are on a planet, racing at 107,000 km/hr around the fiery inferno that is our Sun? To realise that most of your body is just empty space? That most of the atoms in your body were made in a supernova millions of years ago?

Physics has helped me in my life. Doing a physics degree means I now have a job that I find enjoyable, stimulating and meaningful — and because there aren’t enough physics teachers I have job security, which I do not take for granted. But more than that, studying physics has helped enrich my life by filling it with wonder, by helping me appreciate the workings of the technology I use, and making me marvel at the mind boggling complexity of the world we live in. I love physics. I couldn’t imagine being without it.