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Author(s): The Open University

When a membrane that is stretched over a circular frame is struck, energy is supplied, which again causes the membrane to vibrate in a number of modes simultaneously.

The first six modes in which the circular membrane can vibrate are shown in Figure 20. The diagrams comprise circles that are conce
Author(s): The Open University

In a wind instrument, the air column is the primary vibrator. To excite the air column, a musician either blows across it (e.g. flute) or blows down it via a mouthpiece (e.g. trumpet) or reed (e.g. oboe). This supplies energy, which starts the air column vibrating. The air column isn't just forced to vibrate in one single mode; as with the string, it vibrates in a combination of several modes.

To a good approximation, the air column of a flute is cylindrical with two open ends and, as a
Author(s): The Open University

You learned in the previous section that for standing waves to be set up on a string there must be reflection. A travelling wave reaches the end of the string and is reflected. This results in a second travelling wave, which moves back up the string in the opposite direction to the first wave. The two travelling waves interact to produce a standing wave.

Standing waves are set up in an air column enclosed within a tube in a very similar way. Again there must be reflection. In this case,
Author(s): The Open University

If standing waves are set up when two travelling waves moving in opposite directions interact, then how are standing waves set up on a string and why are they set up only at certain frequencies?

To help answer these questions, I want you first to imagine a length of string that is fixed at one end and held in someone's hand at the other. Suppose the person holding the string flicks their end of the string in such a way that an upward pulse is sent along the string.

As the pulse pa
Author(s): The Open University

You learned earlier that when a musician plays a note on an instrument, they supply it with energy that causes the primary vibrator to oscillate at certain specific frequencies. In Section 5 we are going to look at what determines these specific frequencies for some of the primary vibrators found in different instruments.

In Unit TA212_1 Sound for music technology: an introduction, we talk about travelling waves: that is, waves that propagate outwards away from their sourc
Author(s): The Open University

In filtration, the partially treated water is passed through a medium such as sand or anthracite, which acts as a 'strainer', retaining the fine organic and inorganic material and allowing clean water through. The action of filters is complex and in some types of filter biological action also takes place. Sand filters are used in water treatment to remove the fine particles which cannot be economically removed by sedimentation. They have been effective in removing Cryptosporidium, a pr
Author(s): The Open University

Honey, P. and Mumford, A. (1989) 'Trials and Tribulations', The Guardian, 19 December 1989.
Honey, P. and Mumford, A. (1992) The Manual of Learning Styles, 3rd Edition, Peter Honey Publications Limited, Ardingly House, 10 Linden Avenue, Maidenhead, Berkshire, SL6 6HB.

Author(s): The Open University

One half of the eye at the joint is shown in Figure 38(a), and it shows two breaks in the limbs either side of the pin-hole. Although both appear brittle in this picture, in fact one side showed signs of ductile deformation. The way it had fractured was unique when compared with the other eye
Author(s): The Open University

Writing Poetry
Poetry is a delicate and intricate art form, practised by many people but rarely mastered. In this album, poets Jackie Kay, Paul Muldoon, W.N. Herbert and Jean Breeze talk about their respective approaches and attitudes to poetry. They explore many aspects of their craft, from the initial spark of inspiration and rewriting to more technical matters such as rhyme, using real speech and narrative poetry. This material forms part of the course A175, Writing poetry.Author(s): The OpenLearn team

Start writing plays
In this album, some of our current and most well-respected playwrights offer an insight into the mechanics and beauty of writing for the stage. Contributors include Alan Ayckbourn, David Edgar, Bryony Lavery and Willy Russell, who discuss their own work and the pleasures and pitfalls of crafting a script. All of the fundamental topics, from character and structure to dialogue and editing, are covered in detail in a series of entertaining and insightful interviews. This material forms part of The
Author(s): The OpenLearn team

Start writing fiction
This album provides the budding author with everything they need to know about approaching the art of fiction writing. Each track contains discussions and interviews with best-selling novelists from a variety of backgrounds including Alex Garland, Louis de BerniÃ¨res, Abdulrazak Gurnah and Monique Roffey. This enlightening and engaging series tackles the practicalities and pitfalls of writing fiction. It contains invaluable advice on the creation of characters, the structure of narratives and ho
Author(s): The OpenLearn team

Social housing and working class heritage
Would you consider a dilapidated seventies tower block as heritage? In England, some social housing developments have already been given listed status, a level of protection usually associated with castles, monasteries and stately homes. Others are considered as a failed experiment by an outmoded welfare state, fit only for demolition. In this album, we see working class residents of one such estate fighting for its survival. By doing so, they may be challenging some of our fundamental assumptio
Author(s): The OpenLearn team

The Arts Past and Present: Ireland
Do we use our buildings to declare who we are? How far does our heritage influence our collective identity? This insightful album reveals Ireland's shifting attitudes towards its cultural heritage. In 1922 when it broke free of British rule to become an independent nation state, the Irish nationalists abandoned high-profile buildings like Dublin Castle as it was symbolic of their British oppressors, and it fell into ruin. Yet they proudly restored older sites like Cashel and New Grange, which i
Author(s): The OpenLearn team

Myth at the heart of the Roman Empire
How and why did ancient Romans use myth to validate their power? Emperor Augustus legitimised his rule by entwining his own ancestry with the mythical stories of Rome's foundation, and created a divine aura around Rome as capital of the vast empire. This album visits key emblems associated with Rome's beginnings: the Forum and the Capitoline Hill with its statue of the she-wolf and Romulus and Remus; the Emperor Augustus's palace and ceremonial altar, and the 17th Century D'Arpino frescos of fou
Author(s): The OpenLearn team

Myth in the Greek and Roman Worlds: the Temple of Diana at Nemi
How was mythology used by ancient Romans in their everyday lives? At Nemi to the south of Rome, the sanctuary of the goddess Diana provides us with a snapshot of Roman life and society. This album explores some of the fragments of objects found at the site of Diana's temple, such as a street entertainer's clay lamp, an ex-slave's votive statue and a miniature model of the Temple itself. Containing significant clues about social mobility, these cult objects reveal how lower social classes used my
Author(s): The OpenLearn team

Veiling: Tradition, Identity and Fashion
Why do Muslim women wear the hijab? How do they reconcile different approaches to veiling between generations, across different geographical regions and in different cultural and social environments? How do they negotiate diverse social and cultural influences, pressures and expectations, legal constraints, practical challenges and fashion trends? In this collection we explore the extraordinary range of different styles of Muslim dress and the emotions people can invest in them. Track 1 looks at
Author(s): The OpenLearn team

Women Writers: Voices in Transition
In the last century which women writers have truly challenged the existing forms of literature? How did they make their voices heard using brand new techniques and styles? For centuries there have been women writers who have changed the face of literature, but we tend to talk of their lives and work in very certain terms. This series of video-slideshows reveals how writing and reputation are often forged in transition, uncertainty and change. In these 4 films we re-examine the lives, work and in
Author(s): The OpenLearn team

Thought and Experience
This album contains fascinating and engrossing interviews with several leading philosophers concerning, primarily, the exploration of four topics: emotion; thought and language; imagination and creativity; consciousness. The interviews contain lively debates from differing philosophical viewpoints, discussions about theoretical thought experiments and the examination of theories developed by philosophers such as Aristotle, Decartes, Galileo, and Hume as well as predictions regarding the future
Author(s): The iTunes U team

One of the most surprising aspects of quantum physics is the ability of particles to pass through regions that they are classically forbidden from entering. This is the phenomenon of quantum-mechanical tunnelling that was mentioned in SessionÂ 1.

In Session 4 we first demonstrate the phenomenon of tunnelling with the ai
Author(s): The Open University