Well, University of Cambridge’s Professor Holger Babinsky has created a 1-minute video  he hopes will answer that question.

In so doing, he is finally laying to rest a commonly used yet misleading explanation of how wings lift.

“A wing lifts when the air pressure above it is lowered. [...]]]> Ever wondered how a bird actually flies?

Well, University of Cambridge’s Professor Holger Babinsky has created a 1-minute video  he hopes will answer that question.

In so doing, he is finally laying to rest a commonly used yet misleading explanation of how wings lift.

“A wing lifts when the air pressure above it is lowered. It’s often said that this happens because the airflow moving over the top, curved surface has a longer distance to travel and needs to go faster to have the same transit time as the air travelling along the lower, flat surface. But this is wrong,” he explained.

“I don’t know when the explanation first surfaced but it’s been around for decades. You find it taught in textbooks, explained on television and even described in aircraft manuals for pilots. In the worst case, it can lead to a fundamental misunderstanding of some of the most important principles of aerodynamics.”

To show that this common explanation is wrong, Babinsky filmed pulses of smoke flowing around an aerofoil (the shape of a wing in cross-section). When the video is paused, it’s clear that the transit times above and below the wing are not equal: the air moves faster over the top surface and has already gone past the end of the wing by the time the flow below the aerofoil reaches the end of the lower surface.

“What actually causes lift is introducing a shape into the airflow, which curves the streamlines and introduces pressure changes – lower pressure on the upper surface and higher pressure on the lower surface,” clarified Babinsky, from the Department of Engineering. “This is why a flat surface like a sail is able to cause lift – here the distance on each side is the same but it is slightly curved when it is rigged and so it acts as an aerofoil. In other words, it’s the curvature that creates lift, not the distance.”

Babinsky is quick to stress that he is far from the only aerodynamicist who is frustrated by the perpetuation of the myth: colleagues have in the past expressed their concerns in print and online.

Where he hopes his video will help debunk the myth once and for all is by providing a quick and visual demonstration to show that the most commonly used explanation cannot possibly be correct. The original video, created by Babinsky a few years ago using a wind tunnel, has now been re-edited in high quality with a voice-over in which he explains the phenomenon as it happens.

Babinsky’s research focuses on the fundamental aspects of aerodynamics as they relate to aircraft wings, Formula I racing cars, articulated lorries and wind turbines. One of his visions is to design a wing that will enable aircraft to fly faster and more efficiently. Using a massive wind tunnel within the Department of Engineering, Babinsky and his team have been modelling the shockwaves that are created on aircraft wings and that restrict the plane’s top speed.

The newly released video will support lectures Babinsky will be giving as part of a series of University of Cambridge Subject Masterclasses aimed at Year 12 school children: “It’s important to put out this video because when I give this lecture to school kids I start by giving the wrong explanation and asking who has heard it and every time 95% of the audience puts their hand up. Only a handful will know that it is wrong.”

When linguists talk about unconscious or implicit language learning, they don’t mean learning while you sleep. Rather, they are talking about one of the most intriguing of [...]]]> I’ve always been fascinated by our ability to learn a language or languages. I came across the following article from Cambridge University which I thought worth sharing.

When linguists talk about unconscious or implicit language learning, they don’t mean learning while you sleep. Rather, they are talking about one of the most intriguing of all mental phenomena: the ability to learn the complex and subtle regularities that underlie a language without even realising.

For children, such ‘implicit’ language learning seems to happen spontaneously in the first few years of life; yet, in adulthood, learning a second language is generally far from effortless and has varied success.

So marked is the difference between first- and second-language learning – at least when it takes the form of classroom learning – it might suggest that implicit learning makes no significant contribution to learning a second language. Or it may indicate that typical foreign language teaching doesn’t take full advantage of the process.

The challenge that faces linguists is how to test whether implicit learning is taking place. How can you differentiate between a person consciously recognising a certain pattern or rule in the language they are learning and the same person unconsciously knowing that something sounds right simply because their brain has judged it to be right?

The new approach to solving the puzzle taken by Dr John Williams at the Department of Theoretical and Applied Linguistics at the UNiversity of Cambridge and his collaborator, Dr Janny Leung from the University of Hong Kong, has been to invent an artificial language. Participants were tested to see whether they correctly acquired, over periods as short as one hour, an understanding of patterns embedded within the artificial language.

An example of their technique is to teach participants four novel forms of the word ‘the’ (gi, ro, ul and ne), telling them that the forms encode a certain meaningful dimension (e.g. gi and ro should be used for describing near objects, ul and ne for far objects). The aim is to see if the participants can spontaneously pick up a correlation with another, hidden, meaning (e.g. that gi and ul should be used with animate nouns and ro and ne with inanimate nouns). The novel forms are embedded in English phrases such as ‘I was terrified when I turned around and saw gi lion right behind me’.

Do they pick up on the concealed pattern when tested? “The answer is yes,” said Dr Williams, whose research was funded by the Economic and Social Research Council. “We found significantly above-chance selection of sentence constructions that were ‘grammatically correct’ according to the hidden pattern. Yet, the participants had no awareness of what they had learned or how. Moreover, we were able to show learning of the same material by native speakers of two typologically very different languages, English and Cantonese.”

Interestingly, picking up the hidden pattern unconsciously doesn’t always happen – if, for instance, the hidden pattern is linguistically unnatural, such as a correlation with whether an object makes a sound or not. “One explanation could be that certain patterns are more accessible to language learning processes than others. Perhaps our brains are built equipped to expect certain patterns, or perhaps they process some patterns better than others,” he added.

The research provides a window onto unconscious learning processes in the mind and highlights an important element that has practical implications for language teaching. In each test, the learner’s attention was directed to the part of the sentence that contained the hidden pattern. By directing attention, it seems that other elements of the sentence construction are picked up unconsciously.

“In a teaching situation, merely teaching the rules of a language may not be the only answer,” explained Dr Williams. “Instead, using tasks that focus attention on the relevant grammatical forms in language could help learners access unconscious learning pathways in the brain. This would greatly enhance the speed of acquisition of a second language.”

Although cold and gaseous rather than a desert world, the newfound planet Kepler-16b is the closest astronomers have come to discovering a world like that featured in Star Wars.

Like Tatooine, Kepler-16b enjoys a double [...]]]> Astronomers claim to have found a planet similar to Tatooine – the (fictional) home of Luke Skywalker in Star Wars.

Although cold and gaseous rather than a desert world, the newfound planet Kepler-16b is the closest astronomers have come to discovering a world like that featured in Star Wars.

Like Tatooine, Kepler-16b enjoys a double sunset as it circles a pair of stars approximately 200 light-years from Earth.

It’s not thought to harbor life, but its discovery demonstrates the diversity of planets in our galaxy.

“Kepler-16b is the first confirmed, unambiguous example of a circumbinary planet – a planet orbiting not one, but two stars,” said Josh Carter of the Harvard-Smithsonian Center for Astrophysics (CfA). “Once again, we’re finding that our solar system is only one example of the variety of planetary systems nature can create.”

Carter is second author on the study announcing the discovery, which appeared last month in the journal Science.

Kepler-16b weighs about a third as much as Jupiter and has a radius three-fourths that of Jupiter, making it similar to Saturn in both size and mass. It orbits its two parent stars every 229 days at a distance of 65 million miles – similar to Venus’ 225-day orbit.

Both stars are smaller and cooler than our Sun. As a result, Kepler-16b is quite cold, with a surface temperature of around -100 to – 150° Fahrenheit.

NASA’s Kepler mission detected the planet through what is known as a planetary transit – an event where a star dims when a planet crosses in front of it. The planet’s discovery was complicated by the fact that the two stars in the system eclipse each other, causing the total brightness to dim periodically.

Astronomers noticed that the system’s brightness sometimes dipped even when the stars were not eclipsing one another, hinting at a third body. The additional dimming events reappeared at irregular time intervals, indicating that the stars were in different positions in their orbit each time the third body passed. This showed that this third body was circling, not just one, but both stars.

Although Kepler data provided the relative sizes and masses of the stars and planet, astronomers needed more information to get absolute numbers. The crucial missing information came from the Tillinghast Reflector Echelle Spectrograph (TRES) on the 60-inch telescope at the Smithsonian Astrophysical Observatory’s Whipple Observatory in Arizona.

TRES monitored the changing velocity of the primary star as it moved around in its orbit. This yielded an orbital solution that set the scale of the Kepler-16 system. The team found that the two stars orbit each other every 41 days at an average distance of 21 million miles.

“Much of what we know about the sizes of stars comes from such eclipsing binary systems, and most of what we know about the size of planets comes from transits,” said lead author and Kepler scientist Laurance Doyle of the SETI Institute. “Kepler-16 combines the best of both worlds, with stellar eclipses and planetary transits in one system.”

The changes come in the wake of Professor Alison Wolf’s review of vocational education.

The Government claims its changes to the league tables will “ensure schools focus on valued qualifications that make it easier for [...]]]> Education chiefs have announced a shake-up in the types of qualifications which will be included in national school league tables.

The changes come in the wake of Professor Alison Wolf’s review of vocational education.

The Government claims its changes to the league tables will “ensure schools focus on valued qualifications that make it easier for young people to enter good jobs or go on to higher education”.

Teaching uninion the NUT said league tables were being used to punish some schools and called for a fundamental reform of the system rather than the current proposals which it labelled “immaterial”.

All 14-16 qualifications currently count in performance tables whether or not they include external assessment. From 2014, only GCSEs and valued vocational qualifications that meet strict new criteria will be recognised in the tables. All these qualifications will count equally.

Schools will still be able to offer any qualification approved for 14- to 16-year-olds and teachers will still be able to use their professional judgement to offer the qualifications which they believe are right for their pupils. But only those listed by the Government as “rigorous” will count in league tables.

A consultation, to run until the end of September, will help define the rules governing “high-quality qualifications”.

The Govenment proposes that:

• All full-course GCSEs, established iGCSEs and AS levels should continue to count in the tables.
• Only qualifications that have been taught for at least two years with good levels of take-up among 14-16 year olds should be included.
• Only qualifications deemed to offer pupils progression into a broad range of qualifications post-16 rather than a limited number in one or two occupational areas be included.
• Only qualifications which are the size of a GCSE or bigger and have a substantial proportion of external assessment be included.

When the consultation ends a list of qualifications which will feature in future performance tables will be drawn up.

Professor Alison Wolf said: “Pupils need to acquire the broad skills which will enable them to progress in the short term, and to thrive over a lifetime of worldwide economic and industrial change.

“The Government needs to give schools every incentive possible to offer the programmes and qualifications which will achieve this end. In recent years though, schools have been under enormous pressure to pile up league table points. When any qualification under the English sun can contribute these, the pernicious effects are obvious.

“We need a single list of good qualifications which all have the same key structural characteristics, but cover a wide range of content. They need to be stretching, standardised, and to fit easily into a typical pupil’s programme and into a school’s overall timetable.

Schools Minister Nick Gibb said: “Young people should be taking only the best qualifications in academic and vocational subjects that allow them to progress. Reforming the league tables so that they include only those qualifications that allow young people to maximise their potential is long overdue.”

But Christine Blower, General Secretary of the National Union of Teachers,  said: “Yet again we see immaterial changes being made to league tables. What is needed is a fundamental reform of a system which is used more as punishment than a true reflection of what schools are doing rather than more superfluous change.

“It is obvious that these proposals will drive schools to focus on offering only those qualifications that count in League tables. Schools need to feel confident to offer qualifications that are right for the student rather than those that will reflect well in the tables.

“Qualifications have been used as a political football by both past and current governments to provide so-called evidence that their policies are working. They do not stop to consider all the work that has to be put in to meeting these constant changes. Time is needed for change to be embedded in schools and teaching needs to be refined in light of experience to maintain high quality teaching and learning.

“Different vocational qualifications meet the different needs of young people. If we are to truly value vocational training as the Government insists it does, then it needs to stop sending out such conflicting messages about the value of such courses”.

Mark Taylor, from Oxford University’s Department of Sociology, poured over 17,200 questionnaire responses from people born in 1970, which gave details of extra-curricular activities at the age of 16 and their careers at the age of 33.  The findings, which [...]]]> Reading extra-curricular books has a greater effect on career prospects than other activities, research suggests.

Mark Taylor, from Oxford University’s Department of Sociology, poured over 17,200 questionnaire responses from people born in 1970, which gave details of extra-curricular activities at the age of 16 and their careers at the age of 33.  The findings, which have been presented to the British Sociological Association, show girls who had read books at 16 had a 39 per cent probability of a professional or managerial post at 33, but only a 25 per cent chance if they had not.

For boys who read regularly, the figure went up from 48 per cent to 58 per cent.

None of the other activities, such as taking part in sports or activities, socialising, going to museums or galleries or to the cinema or concerts, or practical activities like cooking or sewing, were found to have a significant effect on their careers. Mr Taylor also found that playing computer games frequently did not make it less likely that 16-year-olds would be in a professional or managerial career at 33, but this was linked to a lower chance of going to university.

Mr Taylor said: “According to our results there is something special about reading for pleasure. The positive associations of reading for pleasure aren’t replicated in any other extra-curricular activity, regardless of our expectations.”

He says reading might be a factor because it helps to sharpen the mind or employers feel more comfortable appointing someone with a similarly educated background. It might be simply that students who were already destined for better careers tend to read more anyway.

Reading books was found to be linked with a higher chance of students going to university. For 16-year-old children whose parents worked in admin or sales, their chance of going to university went up from 24 per cent to 35 per cent for boys and from 20 per cent to 30 per cent for girls. If they read books and also did one other cultural activity, such as playing an instrument or going to museums, the chance rose from 24 per cent to 54 per cent for boys and from 20 per cent to 48 per cent for girls. Playing computer games regularly and doing no other activities reduced their chances from 24 per cent to 19 per cent for boys and from 20 per cent to 14 per cent for girls.

The research, based on responses from the British Cohort Study, finds that although reading is linked to a more prestigious career, this does not necessarily mean they will enjoy a higher salary. It shows that none of the extra-curricular activities at 16 were associated with a greater or lesser income at 33.

Furthermore, writers do not usually aim at a narrow audience of like-minded people: they are [...]]]> Correct Methodology
There is never a correct answer in English. Lots of different critics have different viewpoints, different ideological perspectives and different cultural backgrounds: all readers also come to books with different personal histories, prejudices, tastes and emotional backgrounds.

Furthermore, writers do not usually aim at a narrow audience of like-minded people: they are not usually aiming to “preach to the converted”: indeed, the opposite case is truer. Writers are usually, when they are serious writers, aiming to add something new to people’s ways of viewing the world. They are very often writing because they do not find existing worldviews satisfactory, and they are very often aiming to say something to improve the way people understand the world.

Hence, it is by and large nonsensical to try to look for a correct answer. It is certainly a sterile way of reading and suggests that the reader who looks for such sterility does not know much about the business of writing or about the business of reading. Reading, for an experienced reader, is an exciting voyage of discovery, involving changes and readjustments, not confirmations of previously held views.

However, there are rules and expectations within literary study, and you would be foolish to ignore that fact when you study and particularly when you revise.

Firstly, there are people who, through carelessness or ignorance, do not understand the literal aspects of the text. You must obviously understand every word in each text; you must comprehend accurately the plots of your texts; your interpretation of character must also fall somewhere within the agreed parameters. (You can’t understand Catherine Earnshaw as a man in drag, for example, or Heathcliff as a weak-willed bookworm who has no passion in his soul.)

We should also take some trouble to understand each of our texts in terms of its own cultural background, and to embrace the difficulties posed by the fact that each of them was written in a different cultural context from the one you inhabit.

Again, it is implicit in the whole ethos of reading that we should wish to broaden our awareness of the human condition, to take lively interest in the variety of ways we humans can understand life, and in the variety of ways we choose to live life, as well as being excited by the discovery that, despite such variety, it can also make good sense to aim, through our study, to discover what is essentially human. (“The proper study of Mankind is Man.&rdquo

I hope these notes will help you to understand aspects of the novel Wuthering Heights, but I would be happiest if you use them as only a starting point to develop dynamic investigations of your own.

The subject must be studied according to a certain methodology for the study to be judged successful or academically reputable, and it is vital now that you get this correct methodology into your working routines.

Bearing in mind what is said above, and thinking about the fact that you are given only one hour to respond to the examination excerpt and the question asked, what should you be aiming to show your examiner

Firstly, if what is obviously correct (a safe reading) is not of much interest, we should think twice before offering what John Cleese called in Fawlty Towers “the bleeding obvious”. Examples include : “Heathcliff sometimes gets angry… Heathcliff is not a very nice man… Catherine Earnshaw is not always reasonable… Linton Heathcliff is not an athlete … Hareton is not well-mannered;

There is, in other words, a vast number of statements which are indubitably correct but which, when essays are composed largely of them (however much evidence is neatly stacked up to prove the truth of them), the examiner can only conclude that the reader is insecure, timid, unexcited and, frankly, boring.

You sometimes need to use such statements in proofs of more interesting propositions, but the bleeding obvious is not the business of Literature

Secondly, don’t aim just to be original either. That would be to go to the other extreme, and would often make the logical demands on you excessive.

Thirdly, bear in mind that the examiner wants to know that you know what to do with a book and that you have genuinely worked the text, worked with the text, thought deeply about what it says and about how it says it, over the course of your study.

Think of a book as a thinking tool. Just as a cycle is a tool for allowing you to move across terrain, and just as an examiner can work out whether you know how to ride one by watching you perform a certain few manoeuvres, putting your feet in the pedals, your hands on the handlebars, rotating the pedals with your feet, turning the cycle in a tight circle, changing gears appropriately etcetera, the examiner is aiming to see what you can do with text and what kind of thing you have been doing with the book as a whole.

The question you will be asked has been carefully, very, very carefully, designed to test a surprisingly wide range of skills. It will enable the examiner to find out things like this:

Does the candidate pay close attention to words (beyond their literal meaning: the examiner will assume, unless your stupidity makes him question this, that you – being an AS student – have sorted out all the literal meanings of your texts)?

Does the candidate enjoy thinking – and show evidence of skilful thinking? – about the tones, the sound-patterning, the rhythms, the contexts, the ambiguities, the ironies, the incongruities, the associations, the symbolic possibilities, the implications, the registers, etc. of the words, or the combinations of words, which authors so carefully choose?

Or is the reader still stuck at the basic level of reading for meaning alone?

Does the reader know how to read a given passage?

Does the reader just decode it for its literal meaning, or does the reader show signs of active engagement, exploration of the text?

Is the reader, when he explores the text, using intelligent hypotheses, judging the truth or value of them by the disciplined examination of relevant evidence (both in the passage under review, but also – in a good reader – selected judiciously from the evidence available in the novel as a whole)?

Does the reader understand the cultural context of the texts? Does the reader understand how this can change the way it can be read?

Has the reader managed to arrive at a convincing personal reading of the whole text?

(What has he been doing for the year? Is the reading arrived at primitive and basic, or evolved and complex? Has he worked on it?)

It is odd that candidates imagine that, for English, it can be OK to do everything at the last moment: experienced readers know that the kinds of books judged capable of supporting an AS examination continue to develop in the mind for many years.

There are aspects of diction which you need to be aware of. Words can be chosen for a variety of reasons. Mostly, at A-level, the [...]]]> Diction (also known as lexis) is the word we use to describe the careful choice of words by a writer. We can talk about “interesting diction”, “significant …”, “telling…” etc.

There are aspects of diction which you need to be aware of. Words can be chosen for a variety of reasons. Mostly, at A-level, the meaning is taken for granted. That is why you will get few rewards for discussing what a poem “means” at a straightforward level. (“Denotation”, in other words, is taken for granted.)

You may be rewarded for knowing about words’ connotations. With poetry, especially, words’ connotations are very much considered as part of the choice of diction.

You may also be rewarded for spotting ambiguity, or puns, so you need to think about these. Ambiguity is a funny thing: in serious prose, as a rule, ambiguity is considered to be a fault. Clarity is especially important in good prose, and ambiguity (except for comic effect, where it is more likely to be considered as “punning”) is often unhelpful.

In poetry, on the other hand, ambiguity can be important. Theoretically speaking, this may well be because poetry tends to be written where subject-matter is not straightforward, and therefore the exploration of ambiguity can be a valuable tool for cutting deeply into the layers of meaning presented by a suitable poetic subject.
Syntax

Syntax is another tool which has a great deal of significance in the construction of poems. You need to know about subjects, verbs, objects, phrases, clauses, word positions and so on. You need to know about types of sentence too. This needs to be done in class.

Metaphor

This is a huge subject, which needs careful thought. You need to know about the various common kinds of metaphorical language: simile, metaphor, including tenor and vehicle, analogy, personification, reification, synecdoche, metonymy.

Metaphor, according to I.A. Richards in The Philosophy of Rhetoric (1936), consists of: the tenor and vehicle. The tenor is the subject to which attributes are ascribed. The vehicle is the subject from which the attributes are borrowed.

“All the world’s a stage,

And all the men and women merely players

They have their exits and their entrances”

This well known quotation is a good example of a metaphor. In this example, “the world” is compared to a stage, the aim being to describe the world by taking well-known attributes from the stage. In this case, the world is the tenor and the stage is the vehicle. “Men and women” are a secondary tenor and “players” is the vehicle for this secondary tenor. Most importantly a metaphor specifially states that two unlike objects are each other, without using the words ‘like’ or ‘as’.

The metaphor is sometimes further analyzed in terms of the ground and the tension. The ground consists of the similarities between the tenor and the vehicle. The tension of the metaphor consists of the dissimilarities between the tenor and the vehicle. In the above example, the ground begins to be elucidated from the third line: “They have their exits and their entrances.” In the play, Shakespeare continues this metaphor for another twenty lines beyond what is shown here – making it a good example of an extended metaphor.

Types of metaphor

An extended metaphor, or conceit, sets up a principal subject with several subsidiary subjects or comparisons. The above quote from As You Like It is a good example. The world is described as a stage and then men and women are subsidiary subjects that are further described in the same context.

A mixed metaphor is one that leaps, in the course of a figure, to a second identification inconsistent with the first one. Example: “He stepped up to the plate and grabbed the bull by the horns,” where two commonly used metaphors are confused to create a nonsensical image.

A dead metaphor is one in which the sense of a transferred image is not present. Example: “to grasp a concept” or “to gather you’ve understood.” Both of these phrases use a physical action as a metaphor for understanding (itself a metaphor), but in none of these cases do most speakers of English actually visualize the physical action. Dead metaphors, by definition, normally go unnoticed. Some people make a distinction between a “dead metaphor” whose origin most speakers are entirely unaware of (such as “to understand” meaning to stand underneath a concept), and a dormant metaphor, whose metaphorical character people are aware of but rarely think about (such as “to break the ice”). Others, however, use dead metaphor for both of these concepts, and use it more generally as a way of describing metaphorical cliché.

An epic or Homeric simile is an extended metaphor containing details about the vehicle that are not, in fact, necessary for the metaphoric purpose. This can be extended to humorous lengths, for instance: “This is a crisis. A large crisis. In fact, if you’ve got a moment, it’s a twelve-story crisis with a magnificent entrance hall, carpeting throughout, 24-hour porterage and an enormous sign on the roof saying ‘This Is a Large Crisis.’”

A synecdochic metaphor is one in which a small part of something is chosen to represent the whole so as to highlight certain elements of the whole. For example “a pair of ragged claws” represents a crab in The Love Song of J. Alfred Prufrock. Describing the crab in this way gives it the attributes of sharpness and savagery normally associated with claws.

Other types of metaphor have been identified as well, though the nomenclatures are not as universally accepted:

An active metaphor is one which by contrast to a dead metaphor, is not part of daily language and is noticeable as a metaphor. Example: “You are my sun.”

A complex metaphor is one which mounts one identification on another. Example: “That throws some light on the question.” Throwing light is a metaphor and there is no actual light.

A compound or loose metaphor is one that catches the mind with several points of similarity. Example: “He has the wild stag’s foot.” This phrase suggests grace and speed as well as daring.

An absolute or paralogical metaphor (sometimes called an antimetaphor) is one in which there is no discernible point of resemblance between the tenor and the vehicle. Examples:
“The couch is the autobahn of the living room.”
“Six Flags is the aquarium of roller coasters.”

An implicit metaphor is one in which the tenor is not specified but implied. Example: “Shut your trap!” Here, the mouth of the listener is the unspecified tenor. In poetry, an Implicit metaphor is a metaphor implied by the text. Example: In John Donne’s “The Bait” there is an implicit fishing metaphor throughout the entire poem.

A submerged metaphor is one in which the vehicle is implied, or indicated by one aspect. Example: “my winged thought”. Here, the audience must supply the image of the bird.

A simple or tight metaphor is one in which there is but one point of resemblance between the tenor and the vehicle. Example: “Cool it”. In this example, the vehicle, “cool”, is a temperature and nothing else, so the tenor, “it”, can only be grounded to the vehicle by one attribute.

A root metaphor is the underlying association that shapes an individual’s understanding of a situation. Examples would be understanding life as a dangerous journey, seeing life as a hard test, or thinking of life as a good party. A root metaphor is different from the previous types of metaphor in that it is not necessarily an explicit device in language, but a fundamental, often unconscious, assumption.
Religion provides one common source of root metaphors, since birth, marriage, death and other universal life experiences can convey a very different meaning to different people, based on their level or type of religious conditioning or otherwise. For example, some religions see life as a single arrow pointing toward a future endpoint. Others see it as part of an endlessly repeating cycle. In his book World Hypotheses, the philosopher Stephen Pepper coined the term and proposed a theory of four ultimate root metaphors–formism, mechanism, organicism, contextualism.

A conceptual metaphor is an underlying association that is systematic in both language and thought. For example in the the Dylan Thomas poem “Do Not Go Gentle into That Good Night,” the conceptual metaphor of “A Lifetime is a Day” is repeatedly expressed and extended throughout the entire poem. The same conceptual metaphor is the key to solving the Riddle of the Sphinx: “What goes on four legs in the morning, two legs at midday, and three in evening? –A man.” Similar to root metaphors, conceptual metaphors are not only expressed in words, but are also habitual modes of thinking underlying many related metaphoric expressions.
Because they both underlie more than just the surface metaphoric expression, root metaphors and conceptual metaphors are easily confused. For example: In the United States, both conservatives and liberals use ‘family’ metaphors for the national politics, though in different ways. Both types of usage would ultimately resolve to “organic” root metaphors in Pepper’s nomenclature, while Lakoff would distinguish between several different varieties of the “A Nation is A Family” metaphor.

A dying metaphor Coined in his essay Politics and the English Language George Orwell calls a dead metaphor one that has been worn out and is used because it saves people the trouble of developing original language to express an idea. In short, it is a cliché. Example:Achilles heel. Orwell suggests that writers scan their work for such dying forms that they have ‘seen regularly before in print’ and replace them with alternative language patterns.

Finally, the category of metaphor can be further considered to contain the following specialized subsets:

Allegory: An extended metaphor in which a story is told to illustrate an important attribute of the subject
Catachresis: A mixed metaphor (sometimes used by design and sometimes a rhetorical fault)
Parable: An extended metaphor told as an anecdote to illustrate or teach a moral lesson