What is Physics?
What is Physics?
Physics is a plural word used as a singular (rather like "a gallows"). If you look in any dictionary, you will see it defined as:
The branch of science concerned with the nature and properties of matter and energy.
(Oxford English Dictionary)
You will see Physics described as a numerate discipline. The word discipline has rather negative connotations in the way that it is used in the context of being told off. The word actually comes from the Latin discere meaning 'to learn'. It means an area of learning. Numerate means that numbers are involved. It is also described as quantitative. Quantitative is to do with numerical measurements and values.
Like all sciences, Physics involves:
observation of things that happen (phenomena);
analysis (Do the measurements fit a pattern?);
interpretation (What does it mean?);
explanation (Does it make sense?).
Why study Physics?
You are reading this page because you are interested in the Physics. You are about to make a journey that I promise you will be fascinating. You may well be using it to give you grounding in technology, engineering, etc. Or you may be starting to explore Physics for its own sake. I hope you will enjoy the story as much as I do.
Remember that enjoyment and interest are essential for successful study. I can read a text book on sociology or business, but I would not make a good student of either of these subjects. I was my English teacher's worst pupil. I was not very good at literature. Recently I tried to get back into Thomas Hardy, but I found his works as impenetrable now as I did forty-five years ago. (Sorry, Mr Bowen. I did try.)
There are many aspects to the discipline that range from the very small (e.g. sub-atomic particles) to the very large (e.g. the Universe). It explains many everyday phenomena (things that can be observed) which we not only take for granted, for example, the colours we see in the garden or the sounds of the birds gorging at the bird-feeder, but also that we use without thinking about. These notes are brought to you by a laptop computer on my dining room table that uses basic principles of electricity to process words, and images. People, far more clever than I am, have worked out how to get what is an adding machine, to do all the marvellous things that computers can do.
Physics underpins that technology and engineering that benefit all citizens, the hallmark of any civilised society.
Physics is a beautiful subject. Few people can doubt the beauty of the Universe, even though it's not well understood. Few doubt the beauty of natural shapes, many of which are used to great effect in buildings. They use principles of Physics. The many aspects of the subject link together like a big jigsaw puzzle. There can be many ways which can be used to save the same problem. For example the speed of a falling object in a gravity can be worked out with the equations of motion, or by considering the conversion of potential energy into kinetic energy. Gravity and electric fields, which are completely different things, actually behave in a very similar way. All physics can be explained using four fundamental forces, which you will study in these notes.
The late Professor Stephen Hawking, although cruelly trapped in his hideous prison caused by Motor Neurone Disease, described his feelings as he studied the Universe as "one of wonder". I hope you will feel the same.
People in Physics
Physics is international. The discipline crosses all international boundaries, and cannot be claimed by any one country or its nationalist politicians. Indeed it's universal. The Laws of Physics apply not just to The Earth, but also to the furthest flung galaxies.
Physics is about the past, the present, and the future. Much of the physics we will study happened at a time when other significant historical events were happening. It also involved the social aspects of our society, not just in this country, although the class system exaggerated matters. Many physicists were posh people with large estates. Henry Cavendish who worked on gravity was a member of the Cavendish family who, as the Dukes of Devonshire, own Chatsworth House in Derbyshire, and have extensive land holdings in Yorkshire. Alessandro Volta (1745 - 1827) had aristocratic lineage. Much of today's laboratory equipment which we take for granted is based on stuff that was borrowed from the butler's store rooms!
Isaac Newton was not so posh, but still lived in a substantial farmhouse. His mother wanted him to be a farmer; he hated it.
Michael Faraday was from a family that was not well off. At 14, with just the most basic education he was apprenticed to a bookbinder. He educated himself by reading the books in the workshop, particularly Jane Marcet's books that popularised science. He also approached Physics in a non-mathematical way, for the simple reason he wasn't very good at Maths. James Prescott Joule (who gave us the Joule) was from a Manchester brewing family.
Although most physicists in history are men, women latterly made considerable contributions to the advances in Physics. The Physics community is working hard to increase the proportion of women studying and working in Physics. Marie Curie worked on radioactivity in the latter part of the Nineteenth Century. Rosalind Franklin did much work with X-ray crystallography. Lise Meitner was an Austrian physicist who worked on fission. Women are making valuable contributions to Physics nowadays, and will continue to do so in the future.
Peter Higgs (he of the Higgs Boson) was not very good at Physics at school. He found it uninspiring.
As for the future, many young people use these notes. I am sure that some of them will go on to discover something that is ground-breaking. Is it going to be you?
Above all, Physics is about people. Throughout history, men and women have made observations of things they have seen and have used their intellects to make sense of what they have seen and to explain it so that others can understand. They were and are living people who have all the feelings and aspirations of everyone else. They sleep, eat, drink, go to the lavatory, get ill, leap for joy, get angry, get drunk, etc, just like everyone else. Their computers crash just like yours does. They play music. Many are very pleasant people. Sir Isaac Newton was decidedly obnoxious, narcissistic, malicious, and manipulative. Henry Cavendish was desperately shy and socially inept. Both may have had Asperger's syndrome.
Many physicists make good musicians, e.g. Brian May from the legendary group Queen, who is now a leading astrophysicist. The poster-boy for Physics, Brian Cox, is another one who played in a rock band. William Herschel, a Seventeenth Century Astronomer Royal, was a composer, while Albert Einstein was a dab hand at the violin. Johann Wolfgang Goethe, the German poet whose reputation is akin to our William Shakespeare, was a meteorologist and geophysicist.
Not every physicist was born to the subject. Robert Millikan was a Classics scholar (Latin and Greek). His Greek professor nominated him to teach a foundation physics year at Oberlin College, despite Millikan's objections that he knew no physics. "If you can do Greek with me, you can do Physics," was the reply. Millikan did so, keeping a few pages ahead of his students. He found he liked it, and always enjoyed teaching his students. He gained the Nobel Prize for discovering the charge on the electron. The theoretical physicist Edward Witten who works in gravitation and relativity was originally a history graduate.
Physics is a story of human endeavour. It is a story that any student can access. One day a reader of this site may even achieve a Nobel Prize.
The Professional Physicist
What makes a good physicist? The answer is same characteristics of any good scientist. A few characteristics are listed below:
A person who can make links between the different areas of physics;
Someone who is curious;
Someone who is concerned with what is true;
One who can collaborate with others and recognises the part played by all members of their group;
One who communicates clearly and with integrity;
A good learner;
One who weighs up the benefits and risks of their work to society.
In the exams, whatever syllabus you are studying, you may be asked to consider the scientific process, for example how data are validated. (They are obtained fairly from a sound experimental procedure and can be repeated by any scientist.) You may also be asked to consider the impact of the work of scientists on society. An example of this may be the impact of artificial intelligence and robotics on the world of work. As you read these pages over the next couple of years, try to think about the impact that Physics will have on your future. It will change your future in ways I cannot imagine. For example, when I was a teen, computers were massive and mysterious machines housed in huge and secretive buildings. Now you can put one in your pocket. A massive hard drive had a capacity of 100 megabytes (a small picture file). Your flash memory that goes around your neck is 64 gigabytes.
How to Study Physics
Physics has a reputation of being the most difficult of the A-level subjects. At GCSE it enjoys a bad reputation as it's often badly taught in classes where there is an atmosphere of wilful non-achievement. If you approach it with fear and trepidation, that reputation will be self-fulfilling.
It is true that you have to learn many facts, and there is a lot of numerical content. Imagine trying to explain relationships in physics without numbers - it would very wordy at best. In many cases it would be almost impossible. However, the numerical content is basically processing a few numbers to get another number. There are many equations in physics code which may seem off-putting. They are the rules of Physics summed up in short-hand. Do not try to learn equations parrot-fashion. Most are written down on a datasheet.
Successful study, like with all other subjects, depends on effective practice. I know this stuff, not because I am particularly brainy, but because I have practised it. To succeed, you should do the following:
If your course gives you 5 hours teaching time per week, you should spend at least 5 hours a week outside class time. This is the expectation for all subjects in all A-levels in all schools and colleges.
Read around the topic using a good textbook. Your tutor will recommend one. A textbook may be low-tech, but it doesn't crash. Its batteries don't run out. It is easy to carry about and can be used anywhere. It looks good on the shelf. It may invoke happy memories when you are a grandfather or grandmother.
Use web-based resources. (You are using one already!) The internet stores a whole library of learning. There are lots of video clips that explain physics concepts. There are animations and tutorials. Use whichever make most sense to you. However make sure that what you are looking at is actually on the syllabus. If in doubt, get your tutor to advise you.
Understand the Physics. It is NOT an exercise in Applied Mathematics.
You do not have to be a mathematician to do Physics A-level. However, if you are going to do it at university level, you will need to do A-level Mathematics.
Maths is a tool, as essential to physics as a set-square is to a joiner. But Maths is not the be-all and end-all of Physics. It's amazing how many mathematicians can't do physics. I know. Almost all my maths colleagues said they could not do physics.
Practise questions. Look up the answer. If you get the answer wrong, don't get upset. You may find it helpful to start at the answer, and work backward to the question.
Learn from your mistakes. We all make mistakes.
Work with another student. Discuss homework with each other, but don't copy off each other. Submit your own versions of the homework in your own words. (My own approach to students who copied work was to share out the marks. If the script, copied by two students, was worth 16/20, each student would get 8/20.)
Support others by teaching them things you know. There is nothing like having to teach something to make you learn it. I had to do it - and get it right. (As a teacher, you have to convince your students you know what you are talking about, even if you are only three pages ahead of them in the book.) It does become easier with practice.
Meet the deadlines. Don't waste time making excuses.
Read the feedback from your tutor. This might be of variable quality. Your tutor is human as well and gets tired.
Use your tutors. They will offer support tutorials, especially as exams approach.
Review your previous studies regularly. Remember that you will have questions in the A-level exam on what you did in the first year.
Remember that Physics is there to be enjoyed. There will be times when it will be hard graft. Meaningful achievement is the result of effort and hard graft. In an age of instant entertainment, self-discipline is often derided as old-fashioned. But many young students get down to it and achieve. You can too.
Studying AQA Physics
The tutorials on these pages were written for the AQA Modular syllabus. The structure of the site reflects this. I have more recently added material for other syllabuses in the appropriate places. I hope that this will help students who are studying not only the physics syllabuses in England (AQA, Edexcel, and OCR), but also Scottish, Welsh, and Irish (both north and south of the border). You will find your syllabus HERE. If you aren't sure what syllabus you are doing, ask your tutor.
When you study A level Physics with the AQA syllabus, you will cover in the first year (not necessarily in this order):
In the second year (which your teacher or tutor might still call A2), you will study:
In the A-level exam, you will be tested (at a more challenging level) topics you have studied in the first year.
There are five optional topics for AQA (usually chosen by your teacher, unless you are part of a very large centre where there are at least five teachers, each offering one). These are:
Engineering Physics (Applied Physics);
Turning Points in Physics;
You will also do a number of required practicals which are assessed for your A level (but not AS level).
The order you find the topics on this site represent the order in which I taught them with my students. It also reflects the order of the old modular syllabus. Your tutor may well do things in a different order, depending on the schemes of work within your department. As long as you cover everything, it doesn't matter.
In the AS topics there will be bits that will be tested in the A-level only. These will be made clear at the time. The AS material has a blue header, while the A-level material has a dark blue header.
AS level material
Remember that A-level students will need to know the AS level stuff.
These notes are for the AQA syllabus A. You may be doing a different syllabus. The physics is the same, regardless of the syllabus. You are most welcome. Later, I intend to add topics that are covered by other syllabuses.
My Journey into Physics
I think Physics is the best subject. I would say that, wouldn't I? I was a physics teacher. In these pages I share with you my notes on the subject in the hope that they will make a difference, and that my enjoyment of Physics will rub off onto you. If I can do it, you can do it as well, if not better - as my thoughts below will demonstrate.
As a teenager I was a very indifferent student. I was pretty clueless when my first copy of Abbott was handed to me. (It was big and heavy.) I still see them in schools; they're like old friends. If Mr Maslin and Mr Roscoe, both of whom taught me in the nineteen seventies, are still alive, they will testify to that. If they had known that fifteen years later I too was a physics teacher, they would have fallen on the floor laughing (or lain in a darkened room in despair). Despite the many pious statements about successful study at Physics that I have made, I did few of them. I remember struggling with parallel circuits. I picked up my interest in electricity through my interest in model trains. I learned about voltages and currents by setting up my trains. There was a lot of trial and error, but I learned bit by bit. My first escapades into electronics were through making model train controllers. Again these were through trial and error and rather crudely built.
I wanted to be a doctor, but it was clear that I would never have made the grades. I would have made a lousy doctor anyway; my bedside manner would have been appalling. I ended up as getting a degree in Biology. How, I don't know - when I look at my marks, I genuinely wonder how I succeeded at all.
I would describe what passed for my career as a series of pratfalls, blunders, and car crashes (figurative). After one such metaphorical car-crash, I retrained as a physics teacher. Although being a university student again at the age of thirty was quite a culture-shock, I have quite fond memories of my course at Sheffield.
My career as a teacher started with naive idealism and optimism, which was soon snuffed out. Since then it has blundered from pratfall to blunder to (figurative) car crash. I progressed from being pretentious to being pompous. Then to a cynical old curmudgeon. More latterly I have transitioned to the status of an irrelevant old fart. The cynicism that has characterised my career has been towards the education system in England, its management, and political masters, driven by numbers, results, spreadsheets, targets, and league tables. It has NEVER arisen from Physics.
The paragraph above is jaded, negative, and depressing. To counter that I would say that the vast majority of my pupils that I have taught have been lovely people. They are biddable, polite, and considerate. I have been privileged beyond all measure to have taught excellent young people who are far brighter than I. I have helped them to get into the top universities and they will achieve more than I ever did. I am confident that one or two will become household names. Some have come from wealthy and supportive homes, but others have been brought up by single parents in deprived areas. One arrived from a Iran at our college as a seventeen-year-old refugee with no English. At twenty one, he went to one of Scotland's premier universities. Another student had got indifferent results in his first modules. I did a number of tutorials with him. He and I had conversations in Physics, and waffle would not do. He certainly sharpened up my act, and he ended up with an A*. That is what my job was about.
I have worked with excellent people from all subjects. I have no time whatever for those who say that young people have no manners, or have no work ethic. I have even less time for those who think that things were so much better in the old days. I have found that there are plenty of old people who are rude and ignorant. I would also say that I still enjoy learning new things about Physics.
I have never regretted my journey into Physics. It is a truly worthwhile endeavour, full of wonder. I have taught students who have done far better than I ever have and have achieved more than I ever will. Many of you reading these notes will no doubt follow in their footsteps. That I have helped many hundreds in person or many thousands though this website on their first steps in their physics journey makes it all worthwhile.
I wish you all well. I love my subject. I genuinely hope you will enjoy with wonder the story I have to tell.