MH370 Timeline

I was frustrated not being able to visualise the timeline of events for the duration of Malaysian Airlines flight MH370. So I came up with this. Apologies that it doesn't fit the blog template.

Why 4G Is Unnecessary Hype Marketed Solely to Strip You Of Your Money

Last year it was 3DTV: heavily marketed, despite the fact that nobody really wanted it. It fell somewhat flat.

Now it's 4G mobile networks. Orange and T-Mobile were so keen to part you from your money that they formed a new 4G operator, Everything Everywhere, conveniently complexifying their plans and packages in the process.

However, 4G is not what you need from a network.

4G is sold as giving you access to everything you want, whenever you want it. Here's some news: 3G already did that. 3G is fast enough to stream live video at perfectly sufficient quality to watch it on your mobile device without feeling hard done by. 3G will let you download large files (apps and system updates), loads web pages quicker than you can read them, and where I'm writing at the moment is significantly (around 10x) faster than the local fixed-line broadband.

I use 3G networks to support my businesses (both on a handset and through a 3G "dongle" access point, which I use in lieu of fixed broadband). The coverage is good, but the speed is excellent. If I want to download something quickly, I'll use 3G, not fixed broadband.

So what benefit does 4G bring? It'll let you do things you could already do fast enough, faster. If you want to download a system update for your phone, you can do so a bit faster. If you want to watch high-quality video, or listen to the radio live through your mobile device... well, you could already do that on 3G. So in this respect you've gained nothing.

However, 4G also gives you a massive hole in your wallet. At the time of writing a typical 4G contract with EE costs a massive £52.99, capped at 10GB! In comparison, 3 are offering unlimited data on 3G for £15 - less than a third of the cost.

But here's the thing. 10GB of data is all well and good until it runs out. And at 4G speeds, if you're using it to access everything everywhere as the marketing execs want you to, it'll run out pretty quickly. You'll have to turn off automatic download of app updates and music on your phone; if you're using a laptop, you'll need to make sure it's not downloading system files in the background, or updating large apps. Otherwise you'll reach the end of the data allowance before the end of the month, at which point you either have access to nothing, nowhere, or you have to pay a hefty top-up fee.

What you really want from a network isn't faster-than-3G speeds. It's unlimited data. It's the quantity of data you have access to - not the speed - which makes your life simple, easy and hassle-free. With unlimited data you can watch exactly what you want, when you want. You can update your operating system and apps automatically in the background. You can sit watching YouTube videos of cats without worrying that you're about to hit the data buffers. Use iPlayer to catch up with TV you've missed. Listen to your favourite radio station all day over the Internet because you don't have a DAB radio or decent reception.

In fact, if you were looking for a catchy marketing slogan for this concept of unlimited, fast-enough data, you could term it "Everything, Everywhere." Shame they already coined that to sell you some crap you didn't need.

Don't bother with 4G. Save your money and get an unlimited-data 3G contract. It's what you actually need out of a contract. (And if you go with 3, as a bonus they're gradually introducing 4G speeds to their existing unlimited 3G contracts.)

Eight Essential Things Everyone Needs To Know About Passwords

Password security has been in the news again this week, as hackers have harvested millions of passwords from computers infected with malware.

Anybody using the internet for anything at all needs to be aware of a few basic things about passwords. If you understand why you're supposed to do something, you're more likely to do it.

If you don't already know what I'm about to say, take some time to read this; a few minutes invested now will save you a whole bunch of pain in the future.

By the way, I don't claim to be an expert, and experts will no doubt pick endless holes in this advice. I'm working on the basis that the basics, explained succinctly, are more valuable than the whole story explained inaccessibly.

Hashing

When you choose a password for a website, the website uses a system called hashing to protect your password. Using a mathematical formula, the website turns your password into a new sequence of letters and numbers, called a hash, in such a way that you can't easily get back to the password from the hash.

This is important, because if the website stored your password as plain text instead of a hash, anybody gaining access to the files on the website would be able to see your password straight away.

A few websites don't do this basic level of security. In particular, any website which sends you an email containing your actual password is almost certainly not hashing it. You should avoid these websites like the plague, because they are run by idiots. (Not only are they highly vulnerable to hacking, but anybody who can read your email - which is not technically difficult at all - can see your password.)

Hacking and Cracking

The most common way hackers get hold of user information is by hacking a website - accessing it without authorisation. There are various ways to do this. You can't stop any of them, so don't worry about trying, unless you're a website administrator, in which case your job should depend on it.

You might think that even if hackers can access the hashed files containing your password, they can't see the password. This is correct. However, if they gain access to the file containing the hashes, hackers can use password-guessing software to work out (crack) your password. This software can generate millions of potential passwords in a fraction of a second, and hash them. It then compares the hashes it creates with the ones in the hash file from the website. If the hashes match, the hacker has just guessed your password.

You may have read about hackers using "social engineering" to guess people's passwords - trying different combinations of important names, dates etc, or ringing up pretending to be your bank and just asking for it - but in reality, unless you're a high-profile international target for organised crime (in which case pay a consultant, instead of reading this article), or you're the victim of a random phishing scam, this is never realistically going to happen to you. Unless you willingly give out your password to somebody over the phone or in an email, password-guessing software is by far the easiest way for somebody to crack your password.

To defeat this method, you need a password which the password-guessing software can't guess. So how does it guess passwords?

Common Passwords

The software will start by going through a list of the most common known passwords. These include all the passwords people who don't know how to make up a good password will use: 123456, password, iamcool, qwerty, 111111 and hundreds more. (Security consultant Graham Cluley analysed a recent password hack and lists the top 50 passwords it revealed.)

If you use any of these, your password can be guessed in a tiny fraction of a second. You should not have any illusion of any security whatsoever. Assume anybody can access any information protected by such passwords. Change them, now. (Actually, finish reading this article first, otherwise you'll probably just change them to something equally pointless.)

Dictionary Passwords

The password-guessing software will next go through millions of words contained in a normal dictionary, presumably starting at "aardvark" and going on through to "zygote". You're probably already smugly thinking - but ha, I don't use the word "zygote", I cunningly replaced the letters with numbers to get "zyg0t3". Unfortunately, the password-guessing software already knows this and will try all the common substitutions too.

Dictionary words with numbers substituted are not secure. The dictionaries this software uses include many words in many languages, including names, places, bands, etc. So "d4ftpunk" will fall in less than a second.

You can try to generate a password that isn't likely to be in a dictionary. But assume that pretty much any meaningful word or short combination of them ("momof3g8kids", "Oscar+emmy2") will fall prey to this type of attack. Fear not, there are other options.

Brute Force

Once the password-guessing software has tried the easier methods above, it will resort to brute force. Starting with a, b, c, it will then go through every combination of letters and numbers to try out all possible combinations. In the light of this approach, picking a good password might sound a bit futile; surely everything will be guessed, in the end. However, it takes time to try all these combinations. All you have to do is make sure the time taken to guess your password is impractically long.

Assuming 36 characters (A-Z and 0-9), there are 36 possible one-letter passwords, and 36x36=1,296  2-letter passwords, through to 36^6=2.1 billion combinations for a 6-letter password. A fast computer can still hash 2.1 billion passwords in a few minutes (about 4 minutes, in fact). But each time you add another character to the length of the password, it takes 36 times longer to guess.

Use a 16-character dictionary-resistant password and there are 8,000,000,000,000,000,000,000,000 different possible combinations of the basic 36 characters. Even for a powerful computer, it's not trivial to go through all these options. Using basic punctuation as well as letters and numbers adds combinations, so adds security.

So, it's possible to outwit the password-guessing software simply by choosing a long password. But how are you going to remember a long password? You could try only using a single password for everything, but...

Reusing Passwords

A good proportion of users (ie nearly everybody) uses the same password for different websites. Why is this a problem? Well, any hacker obtaining your Facebook password can potentially then access your Amazon account, Yahoo Mail, PayPal, eBay, KinkyGoats.com and so on. This is particularly a problem with email accounts, where the hacker can then use the email account to reset passwords on other services too.

The bottom line here is: never reuse passwords. It's like carrying around 20 identical keys, on separate keyrings, each of which can access your car, your house, your wallet, your credit cards, etc. Lose a single keyring and you've compromised everything.

If you really have to, you could maybe consider reusing a single password for websites which don't give hackers any way to access financial information (eg your BBC Online password which allows you to comment on articles, but not Amazon, which would allow people to make financial transactions on your behalf.) But don't come crying to me when somebody starts impersonating you online.

Password Strategies

Password Management Software

The most effective way to generate a long, secure password is to use a piece of software to do it for you, randomly. (Humans are basically hopeless at generating anything randomly.) However, in most cases, this means you won't be able to remember the password. I've just used 1Password to generate me a nice secure 20-character password, and it came up with pCnVtG4}8[tA,?aXGLEv. This is nice and secure, but even trying to remember it is a complete non-starter.

Therefore if you choose this approach, you'll need to use a piece of software to remember your passwords for you. There are several out there. I use 1Password, which runs on my Mac, iPhone and iPad, and would also run on my PC if I had one. It cost me money, but I'd rather spend a few quid on some well-crafted software than deal with having my identity stolen online :)

Beware! Password management software generally uses a single master password to encrypt all your other passwords. Anybody guessing this password will have access to your entire digital empire. However, if you only store the password file on your laptop, they would need access to your laptop to even begin to start guessing your master password. If the master password itself is secure, you are still reasonably safe at this stage. (Ideally you will also be encrypting your hard drive, as I do - this is a whole nother topic however.)

1Password, like other software, also allows me to sync my password file between several devices (laptop, iPhone, iPad) using third party services such as Dropbox. If I use this, my password file will be stored on Dropbox's servers, where it will also be accessible to anybody who has legitimate or unauthorised access to these servers (ie Dropbox's staff, the NSA, GCHQ, Russian crime syndicates, etc). By using such sync services, I have to accept that I'm making my password file itself much more vulnerable to brute-force attack.

One of many benefits of password management software is that you seldom, if ever, need to type in passwords. 1Password will automatically fill in passwords for me, when I authorise it to do so.

Manual Password Generation

If you're reading this, it's probable that you're not a password expert and hence find the prospect of installing and running password management software a little unpleasant. Don't fear; there are still ways to make sure your passwords are secure.

On the basis that, in the password world, longer is better, the simplest approach is to use multiple words, one after another, to make a single long passphrase. The online comic XKCD popularised this approach; I suggest you don't use "correcthorsebatterystaple" as your password, as it's probably made it into the password-guessing dictionaries already.

If the password-guessing software has a million words in its dictionary, then putting 4 of them one after the other leads to 1,000,000^4, or 1,000,000,000,000,000,000,000,000, different possibilities.

Even better, put a random number in the middle of your passphrase ("correcthorse7556batterystaple"). Even if you use the same number in the middle of all your passwords, unless somebody is deliberately targeting your various passwords individually from a known password (in which case you have more problems than this article can solve) they're not going to be able to crack this using brute force, for some time at least.

How do you then remember all these passwords? Well, if you're going to make a note of them, do so on paper, not on a computer. Yes, if somebody steals the paper, all your passwords are compromised, but it is far more likely that somebody can access your computer remotely than your house will be burgled. I don't really recommend this, but do it if you have to. However, try to make things a little harder for any would-be thieves, for example by writing down your passwords with your random 4-digit number (above) left out of the middle of all of them. Few burglars are going to sit around trying all possible ways of adding information to a paper list of passwords, just to get access to your Amazon account.

Summary

To distil this down a little:

1. Use long passwords. At least 16 characters. Ideally 20. Letters and numbers. Maybe some punctuation too.
2. Never use the same passwords for different websites.
3. Invest in password-management software, if you're confident you can use it properly.
4. ...but make sure your password file is not vulnerable.

Two Things Every A-Level, College and University Student Should Know

Facebook post 1: "I've just been working on my essay for the last twelve hours solid [yeah, right] and Word crashed and deleted it and now I've lost everything!"

Or, "My laptop just died / my memory stick broke and I've lost my entire dissertation."

Entirely avoidable. At zero cost. If you don't solve this, you're an idiot, and I reserve the right to laugh mockingly at your pitiful cries of anguish.

1. Sign up for a Dropbox account. (Other providers are available.)
2. Download the app for your PC, Mac or even Linux box.
3. Make sure you save ALL your uni work into your Dropbox folder. You can even move your My Documents folder into Dropbox, so everything you save goes there (if you have enough space).

Why do this?

• All your work is backed up online. If your laptop is lost or breaks, no worries - all your data is safely out there in the Cloud.
• If you accidentally delete or overwrite a file, or Word messes it up for you (yeah, sure it did) then just go to the Dropbox website and recover a previous version.
• Battery flat? Need to access your files from the library and don't have your laptop? Just log into the Dropbox website and bingo, everything's there.
• Want to just check something in a document quickly? Access Dropbox from your tablet or smartphone too.

Facebook post 2: "I hate Harvard referencing! It'll be the death of me!"

Er, you do know that Microsoft Word will do all that nasty referencing for you? Including all the silly formatting? And also deal with referencing PDFs and websites and anything else you need?

There are a few guides to do this (Google it), but here's one of them, which also explains how to download additional files to support your university's preferred referencing style.

Simply add details of any work you reference in an easy-to-use database in Word, then in a single click you can add a pointer to any reference, or even specific pages of it. If you use the same references in multiple essays, you can even copy them between files.

Word will automatically insert a fully-formatted, auto-updating list of all your references at the end of your work. It's so easy it's not even funny.

You're welcome.

How Not to Write Pseudo-Academic Papers

I'm currently reading through a whole load of "academic" papers. (I use quotes because they're trying to be academic; they're not peer reviewed.)

Here are some notes for those trying to make their papers as difficult to read as possible:

• Use single line spacing. Don't use paragraphs unless you are forced to. Try to get at least 15-20 sentences into a paragraph.
• Make your abstract a single, large block of text with no paragraph breaks, ideally at least a page in length. The timbre should resemble instructions from a drill sergeant.
• When using complex formulae, write a single sentence that attempts to describe each term in the formula, one after the other; a description of the formula, if you like. All that mathematical notation makes everything a little too clear.
• Avoid diagrams at all costs. If you are forced to use diagrams, put them at a random point in the text, nowhere near the discussion point.
• Use commas, sparingly ideally at arbitrary places, in the sentence so the reader has to read each sentence, several times in order to get the sense of it.
• If making an important point upon which the whole of the rest of the paper is predicated, do it in as few words as possible, with no explanation. Avoid anything which might draw attention to it.

8 Golden Rules to Not Look Like a Powerpoint Idiot

Powerpoint is a much-maligned piece of software. However, like all software tools, it's only what the user makes of it.

Powerpoint presentations can be dire, or dull, or inspirational, or magnificent, depending wholly on the expertise of the person driving the slideshow. I would suggest there are few pieces of business software more capable of making somebody look like an an incompetent fool in a short space of time.

Follow these golden rules to make sure your next Powerpoint audience leaves with a buzz and a smile on their face.

Never, ever, ever, read the bloody slides out

Everybody knows this, but I've so often seen people who bill themselves as presentation experts reading out the bullet points on their slides. To do this is to entirely misunderstand the reason behind using a slideshow:

Powerpoint is not an autocue

The slides are there to give the audience a visual background to what you're talking about. If you're going to write an essay to accompany your talk, you might as well not bother doing the talking - just display the text on the screen, as your audience probably read just as well as you can.

Examples of valid uses of Powerpoint slides might include:

• An image that explains visually something difficult to comprehend verbally
• Some words that summarise succinctly what you might spend 4 minutes discussing
• Several slides forming a narrative structure to give a natural progression to what you're talking about

Less is more

Never truer than with Powerpoint. Keep adding text and arrows and images and you'll end up with a slide deck that looks like it was put together by a hyperactive 7-year-old. Have a look at this alternative take on the infamous leaked NSA Powerpoint slides to see what a professional could have done with the mess you just made.

Use the animation features sparingly, if at all

Never animate every bullet point. (Many do. It looks truly awful.) Keep animations purely for (1) reveals (when you don't want to give away the punchline before the audience has considered a discussion point), and (2) adding clarity to diagrams which lend themselves to a time-based narrative.

Your slideshow isn't there to upstage you. Don't use the weirdest, most esoteric transition you can find:  it makes you look like a cro-magnon discovering Powerpoint for the first time. Dissolve is good enough nine times out of ten.

Try to learn the most basic of design rules

Learn the basics of typography: font families, spacing. Pick colours which contrast cleanly against each other. Pastel colours work better than garish colours (depending on which version of Office you're using, you may want to junk the default colour schemes; some versions allow you to easily pick from a range of alternative palettes.) White on yellow will have your audience wanting to murder you.

Get there half an hour early and for God's sake make sure it works

If you wait until the audience is seated to find out that your presentation doesn't work properly, you'll look like a blundering fool. However, I've seen this happen so many times it's just not funny. As an audience member, if you're prepared to keep me and 399 other professionals waiting because you couldn't be bothered to test your projector in advance, I will spend my time planning how best to lynch you.

Make sure you leave at least half an hour to make sure your laptop connects to the projector, your videos work, your sound works, and you have time to sort these things out in case of problems. Always carry a memory stick to port your slideshow to another computer in case of dire problems.

If using video, check each video specifically works on your output hardware - Powerpoint's handling of video can be patchy at times.

Get a wireless presenter

If you have to hit a key to change slides, you'll be tethered to your laptop throughout the presentation. A wireless presenter tool fits inconspicuously into your hand and gives you the freedom of the whole auditorium while you present. The professionalism and credibility you'll gain is worth far more than the £20 it'll cost you.

Depressingly few non-professional auditoriums properly light the lectern area. Stand somewhere your audience can see you.

Learn the freaking keypresses already

It's painful to watch somebody accidentally skip forward a slide, and then exit their slideshow, start at slide one, and go through every. last. animated. bullet. point. to get back to where they were. Then accidentally press Next once too many times and do it all again... I've seen this happen only too often.

Learn how to navigate the software. It's as simple as: Space, Down Arrow, Right Arrow: go forward.  Left Arrow, Up Arrow: go backwards. If you have to use the right mouse button during your presentation, you're unprepared and unprofessional.

7 Things People of the Future Will Look Back At In Astonishment And Wonder

We look back on the Victorians today and laugh;  about ankles being considered too risqué to be seen in public, and pianos apocryphally having skirts around their legs to hide the piano's ankle;  about their belief in the supernatural, and participation in seances; scientific predictions that they pretty much knew everything there was to know about physics, that ships propelled by a motive force at the stern wouldn't be able to go in straight lines, and later, contradicting Newton, that rockets wouldn't be able to move in space because they had nothing to push against; and at their approach to the the developing field of biology, which involved shooting and often eating anything that was new, and particularly anything that was rare and prized.  By today's standards we find it difficult to comprehend a society that could hold on to these ridiculous notions.

Let's have a look at the the state of our own society, and consider what will be mocked in a hundred, two hundred or five hundred years' time:

Our attitude to resources

"Son, can you imagine that back in the 2000s, people drove around in cars guzzling fossil fuels, knowing full well that they were a finite, irreplaceable resource?  They drove all around the country, often for no good reason.  They took their cars down to the shops when they could have walked!  The richest people drove cars which used up fossil fuels at a much higher rate, and everybody admired how successful they were.  They even made TV programmes dedicated to watching people driving around in the most inefficient cars!"

We make plastic bags from petrochemicals, use them once and throw them away.  PG Tips give away promotional tea bags, each individually wrapped in cellophane, surrounded by cardboard, then wrapped in more cellophane.  We put millions of tonnes of irreplaceable materials into landfill and leave it for somebody else to worry about.

Sustainability of the food chain

"A couple of hundred years ago, did you know people fished and fished until many of the fish species were almost extinct?"

"How did they not realise what they were doing?  Surely they could tell that the fish stocks were running out?"

"Oh, they did.  Scientists showed time and time again that what they were doing wasn't sustainable.  But politicians carried on allowing it to happen, because it protected the jobs of a few thousand people working in the fishing industry.  They risked an entire global ecosystem because of a conservative minority in denial of the evidence."

Animal welfare

"Can you believe that once people thought it was totally acceptable to keep millions of animals in laboratories, to test cosmetics and drugs on them?"

"What about the welfare of the animals?"

"People largely ignored that.  Towards the end of the 20th century there was pressure on the companies involved to improve the conditions they kept the animals in, but most people thought the welfare of the animals wasn't really important, even though they were horrified at what their predecessors in the 18th and 19th centuries did to animals."

"Oh yes - wasn't that when people would buy a dog from a breeder as a pet, bond with it as a puppy, then lose interest and then give it to a charity to have it kept in a cage and then euthanised?"

Discrimination

We already look back at 1950s attitudes to homosexuality and race with horror.  But as I write, an armed white man has just been acquitted of murdering an unarmed black teenager on the basis that he looked like he might be about to do something wrong.  The British media is still covering a story of a little English girl who was kidnapped in Portugal several years ago, whilst I can search the Web and find literally dozens of black and asian children in Britain who are missing without explanation, but whom nobody seems to care much about.

The Church of England is still deeply uncomfortable about the idea that men and women could actually achieve equality, and the concept of somebody getting married to another of the same gender has only just been accepted in Britain against considerable opposition from those who think homosexuality is unnatural or that the right to choose to share your life with a loving partner is arbitrated by a homophobic deity documented in dusty scroll fragments unearthed in the desert and written thousands of years ago by goat herders.

The human body

"Back in the 1990s and 2000s there was a chap who decided to walk from Land's End to John O'Groats with no clothes on.  He was arrested more than 20 times, and imprisoned.  They wouldn't let him out of prison because he had no clothes on!"

"But didn't everybody have the same organs?  Were people actually surprised to see what a naked man looked like?"

"Everybody knew what nudity looked like, because you could access highly sexualised images freely on the Internet.  But the idea of actually seeing such things in public, in a non-sexual context, horrified people."

Tobacco

"In the 1900s, huge multinational companies made a business out of selling people a herb that gave them a good feeling whilst polluting the air around them for everybody else.  Quickly people realised that the herb was also appallingly bad for your health.  People started dying of cancer from it;  those who used it had their life expectancy shortened by ten years on average, and stood a 50% chance of dying from it."

"So didn't the governments care about supporting an industry which survived on the basis of making people addicted to something that would kill them?"

"Governments were highly sensitive to the idea of substances which could harm people;  such things weren't allowed in the food chain, or in pollutants from cars, and were tightly controlled in industry, even if they were only a little bit harmful.  But the tobacco industry was so large and wealthy that it bought control of the governments and made them support its sales & marketing of tobacco, against all scientific advice and public opinion.  Politicians just pretended it wasn't an issue."

"So companies put financial profit above the health and eventual death of their customers?"

"Sure - the society at the time rewarded them handsomely and pretty much encouraged them to do so!"

Superstition

Turn on the TV late at night and you'll see adverts for "psychics" who can apparently predict your future, for a substantial price (not from the kindness of their hearts).  Many daily newspapers have a section devoted to horoscopes - the idea that the pattern of balls of fusioning gas billions of miles away at the approximate time of your birth can influence whether you'll get a job next week.

But millions of us are prepared to accept this, and perpetuate it with our own money, without a shred of evidence to support it, against all reason.  In a few hundred years people will be thinking of this and laughing their socks off, but it's still a pervasive thread in our society.

Do I Need To Take A-Level Maths To Do A-Level Physics?

People often say to me, "Dave, do I need to take A-level maths if I want to do A-level physics?"  Not generally random strangers, mind;  usually Year 11 students, or their parents.

Most schools will tell you emphatically YES.  Some even make it mandatory.  In my experience this is a lot of tosh.

Let's spell it out:  you do NOT need to take A-level maths in order to do well in A-level physics.  A-level physics is full of maths.  But although there's lots of it, there are actually very few mathematical concepts you need to master in order to study A-level physics.

Nearly all of them you will have learned at GCSE (possibly not all that well, but you'll have covered them).  It's really important that you can do these few things well - and you understand how they work, and why.  The rest is just wallpaper.

In fact I'd contend that you don't even need to have studied GCSE maths to understand A-level physics - you could simply learn this handful of things at the beginning of your course, if you had to, although I'd not generally recommend this, as you need to be adept at using them.

Key Skill 1:  re-arranging the subject of an equation

This comes up all the time.  A good GCSE maths teacher will have taught you not only how to do it, but why you do what you do.  I've always been amazed at how few Y12 students really understand how this works;  it's surprisingly simple.  All you have to do is remember three simple rules of equations, which I deal with below.

If you can re-arrange the subject of the following equations for each letter in term, you'll be able to cope with every equation in A-level physics bar one tiny set (see below).
e = ½ m v²
v² = u² + 2as

Key Skill 2:  exponential numbers

This comes up all the time in physics, because we often deal with very large or very small numbers.  For example, the charge of an electron is 1.6 x10^-19 coulombs.  We could write 0.00000000000000000016 coulombs, but we're lazy scientists, so we don't.

You need to understand how the exponential annotation works, but critically, you also need to understand how to use it on your damn calculator!  So many times I've seen highly competent physics students get the wrong answer because they don't know how to use their calculator.  Clue:  use the "EE" or "Exp" button - do NOT type in [1.6] [x] [10] [^] [-19] for example, because if you're in the middle of an equation, your calculator won't know which order to do things in, and you are guaranteed to get the wrong answer.

To see what I mean, calculate z:
z = 3x10^8 / 1x10^3
(Excuse me using ^ instead of superscript - I can't see how to format superscript text here...)
If you get 300,000 (or 3x10^5), you got it right.  If you get 3x10^11, then give yourself a smack on the back of the head, and go and learn to use your calculator properly.

Key Skill 3:  trigonometry

Make sure you can use sine, cosine and tangent;  they come up in most things involving more than one dimension, and when you do simple harmonic motion, you'll begin to understand some of the beauty of them - including some elegance to do with differentiation and integration.

The rest

At A2 you'll need to do a couple of logarithms. Quite honestly, you don't really need to understand logs all that well to get the answers right, although it would be nice - you can just learn the basic rules of how to rearrange these equations. This is primarily when doing half-life and capacitors.

If you are skilled at mental arithmetic, you'll find physics much more straightforward and rewarding. Consider this:

• 8x10^12 / 2x10^8

If you needed a calculator to work this out, consider that this is the same as writing 8/2 x 10^12/10^8.  Well, 8 / 2 = 4, and 10^12 / 10^8 = 10^4, so the answer is simply 4x10^4.

On this note, the ability to quickly estimate (which I learned so well studying Earth Sciences at university) is valuable and will help you avoid making silly mistakes. For example, if a circle has diameter 1.5m, its circumference is about 5 metres, so if something moves round this circle at roughly one rotation per second, its speed is roughly 5m/s. For the purposes of quickly working out the speed of a bunsen burner swinging around on the end of a hose, I don't really care whether pi is 3.1415926535... or 3.14 or 3. 3 and a bit will do. So pi times the diameter is just over 3 x 1.5m, which in my head is not far short of 5m. In an exam I'd work it out; but if I can quickly estimate, I can check my answer mentally and make sure I haven't done something silly with a calculator.

And for heaven's sake make sure you know how to plot a scatter graph (line graph, x-y graph). Clue: the numbers on each axis should go up the same amount each time. You'd be amazed how many A-level physics students forget this at some point.

All you really need to know about equations

So let's go back to these equations.  There are only three things you really need to understand about equations.

Rule 1:  each letter just stands for a number.  Sometimes we know what the number is.  Sometimes we want to find out.  Sometimes the number can only be expressed in terms of other numbers.  But any letter in an equation just stands for a number.

• y = 3 + 2

This is pretty obvious.  We can work out the value of y.  But have you also considered the following:

• distance = 3 km

3 is a number.  k stands for a number:  specifically a thousand.  m also stands for a number;  but one that we can only really express in terms of other numbers, such as speed and time.  So we normally leave m as m.  But we can substitute 1000 for the value of k:

• distance = 3 km = 3 x 1000 x m = 3000m

It sounds obvious when you think about it.  But how many people understood this when they did GCSE maths?
When you have to deal with units of MeV/c², if you know that M means 10^6, one eV = 1.6x10^-19 J, and c² is 9x10^16, you'll breeze it.

Rule 2:  providing you do the same thing to both sides of an equation, it's still valid.  If you do different things to each side, you'll break it.

Rule 3:  anything divided by itself is one.  Anything times one is itself.  This is really useful when we want to re-arrange the subject of an equation.

Example:  we have the formula I = V / R (current = voltage / resistance).  Let's say we need to re-arrange this for V.

It doesn't matter if you can do this straight away in your head:  what's important is what you do and why.

If at this point you thought "ah, we're dividing by R on the right hand side, so we'll times by R on the left hand side", then find whoever taught you how to re-arrange equations and deliver a short, sharp blow to their temple.

We want to get rid of R on the right hand side of the equation.  We know (Rule 3) that anything divided by itself is 1.  So let's multiply the right hand side by R, so we can later divide it by itself to get 1, and get rid of it.

If we're going to do that, we need to do the same to the left hand side (Rule 2).

So we get:

• I R = V R / R

R / R is 1 (Rule 3) and V x 1 is V (Rule 3).  So V R / R is the same as V.

Now we have:

• I R = V

The equals sign works both ways, so if I R = V then V = I R.

Not hard, is it?

We don't often add or subtract things in physics (multiplication and division are seemingly more relevant to the laws of the universe), but if we have equations which have addition or subtraction, simply remember that anything minus itself is zero, anything plus zero is itself, and deal with the addition / subtraction before you divide or multiply.

If you followed the last few paragraphs, then take it from me, you can re-arrange any equation that is going to come up in A-level physics, apart from the logarithm stuff mentioned above, which you can learn as you go along.

5 Things You Were Never Told About Qualifications

I suddenly realised that over the course of some different careers I picked up some things which we were never told at school (or university, or afterwards).  It's obvious when you know it, but if you don't, it may be a bit surprising.

1) GCSE results aren't important (after a few months)

The education system endlessly emphasises the importance of GCSE results.  Looking back however, I notice that my GCSE results were useful precisely twice.  The first, and most important, time was when I applied to do A-levels.  The second time was when I applied for a degree, where they pretty much confirmed my A-level results weren't a fluke.  Apart from that, how many jobs have I secured on the back of my GCSE results?  None.  (Because I did A-levels.)

2) A-level results aren't important either (after a few years)

My A-level results were useful precisely once:  when I applied for a place at university.  Had I had a job at uni (in those days you didn't have to run up massive debts and pay for your place at university) they might have been useful in helping get a student job of a certain type (ie technical / specialist positions - as a barman I don't suppose it would have made a huge difference.)

3) Your degree grade isn't important either

I got a 2:2 in my degree.  I only ever applied for a single job in which this made a difference (it was a graduate training programme at Ford, and to be honest, being denied the chance to apply because I didn't have a 2:1 was probably their loss more than mine.)  The important thing was that I had a degree;  other factors outweighed the grade considerably.

4) Your degree itself isn't important after your first job (unless you're applying for something vocational)

Certainly, having a degree was useful in securing myself my first graduate job.  However, for my second job, the important thing was:  my first job.  Having the degree was an influencing factor, but the experience I had in the field was what won me the second job.

(When I applied to do teacher training, my degree was fairly essential, because the job depended on the knowledge base I had secured.)

5) When it comes to work, your qualifications are only secondary to another, more important, thing

At what point in the interview do you actually secure the position?  Is it when they talk through the qualifications on your CV?  The experience?  Is it when they ask the daft "what's your biggest weakness" question?  Actually, by that time you're probably way too late;  the initial impression you make about the person you are is what generally secures you the job.  If the interviewer picks up that you'll fit in well, and that you're a decent person, you're 90% of the way to getting the job.  (This decision is made within the first half minute or so!)

To put it another way - do I give the job to the person who is well qualified and experienced, but who I think is a bit of a dick, or do I give the job to the person who I instinctively liked when I first started talking to them?  Actually, it's the second.  I suspect the same is often true at university interviews.

Does this mean that grades are a waste of time?  Nope.  Notice I didn't say GCSE results aren't important - I just said they're not important after a few months.

However, what's more important is the person you are and how you come across.  If you are easy to get on with, likeable, professional, confident and good with people, in many cases this will completely outweigh your qualifications throughout your professional career.