When a sound wave reaches the end of an air column, it is clear that it will be reflected if the tube end is closed. You only have to imagine yourself standing some distance, let's say 50 metres, away from a flat wall. If you shout, you will hear an echo â€“ the reflection of the sound wave you projected.

There is one difference, though, between the reflection of a sound wave and the reflection of the wave on a string that you met previously. When a sound wave is reflected from a closed
Author(s): The Open University

When a string is bowed, plucked or struck, energy is supplied that starts the string vibrating. The string doesn't just vibrate in one single mode; instead, it vibrates in a combination of several modes simultaneously. The displacement along the string is the superposition of the standing-wave patterns corresponding to those modes. For example, if the string vibrated only in the first and second modes, the displacement at a given instant of time might appear as shown in 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

One drawback of the amplitude as I have defined it is that although it allows the relative sizes of sine waves to be compared, it does not give a good idea of what a sine wave can deliver in absolute terms. For instance, a sine wave with an amplitude of 10 volts has twice the amplitude of one with an amplitude of 5 volts. But is a power source that delivers a sine wave with an amplitude of 10 volts as powerful as, say, a 10 volt battery? Could you use it to drive a bulb and get the same illum
Author(s): The Open University

The speed of sound has a joint relationship with both the wavelength and the frequency of the sound. To see why, recall that at the end of Section 2.5, in connection with the wave produced by a tuning fork, I said â€˜in the time it has taken for the source to go through one cycle of oscillation, the wave h
Author(s): The Open University

Pressure in the air is related to how closely packed the molecules are. Other things being equal, more closely packed molecules are at a higher pressure than more dispersed molecules. Sound is associated with fluctuations of the air pressure caused by local disturbance. Fluctuations of pressure travel outwards away from the disturbance, carrying energy imparted by the disturbance.

A simple form of local disturbance to air pressure is a vibrating tuning fork. It generates a pressure wave
Author(s): The Open University

There are many more methods that are regarded as systems approaches for managing complexity (e.g. Rosenhead, 1989a; Flood and Carson, 1988; Flood and Jackson, 1991; Mingers and Gill, 1997; Francois, 1997; Flood, 1999; Jackson, 2000). The systems practitioners responsible for developing these come from a varied background, but in the main their experiences are similar to those described for Checkland, Beer, Espejo and the T301 team. All wanted to be able either to take action that stakeholders
Author(s): The Open University

I have already introduced various systems methods. Behind all of these methods, there has generally been a champion, a promoter aided by countless co-workers, students, etc. To paraphrase the French sociologist of technology, Bruno Latour: we are never confronted with a systems method, but with a gamut of weaker and stronger associations; thus understanding what a method is, is the same task as understanding who the people are.

A method, like any social technology, depends on many peopl
Author(s): The Open University

It is possible, as observers, to ascribe a purpose to what we or others do, the actions we take. How particular actions, or activities are construed will differ from observer to observer because of their different perspectives, which arise from their traditions of understanding. For example, in Author(s): The Open University

Initially, I would like you to notice whether and how your appreciation of the phrase â€˜managing complexityâ€™ has changed since you started the unit. As you work through Section 4 you will encounter a number of ways of thinking about complexity that may be new to you, so it becomes important to record your developing understanding. To help you with this, return to your notes on Author(s): The Open University

As outlined in Table 3, ethics within systemic practice are perceived as operating on multiple levels. Like the systems concept of hierarchy, what we perceive to be good at one level might be bad at another. Because an epistemological position must be chosen, rather than taken as a g
Author(s): The Open University

The last activity was a demanding task. People I asked to do it during the writing of this unit, found it took a lot of concentration but it brought up lots of ideas, feelings and suggestions for action. Most of them were also concerned their rich picture might not be good enough. I imagine you will share some of these reactions. If you share any of these concerns, remember there are lots of ways of drawing a good rich picture and almost all rich pictures can be improved. Improving your rich
Author(s): The Open University

The first three activities in Figure 4 are to plan a strategy, then to immerse yourself in an example of complexity, and then represent that complexity through drawing a rich picture. I've selected a rich picture as the focus of this task because it is a means of bringing you into a r
Author(s): The Open University

Not much of this unit conforms to the traditional pattern I mentioned earlier â€“ the theory-example-exercise pattern. In particular, you will find you are expected to discover much of it for yourself. Why is this? This is a legitimate question and deserves a full answer. One year, a student at a residential summer school complained I had not taught him properly. I was, he told me, an expert and so why did I not demonstrate how to tackle the problem he was working on and pass my expertise on
Author(s): The Open University

An innovation that is compatible with the experiences, values and needs of its potential buyers will be adopted more rapidly than one that isn't compatible. For example mobile phones have spread rapidly because they are compatible with social and cultural trends towards faster communications, increased personal mobility and the desirability of high-tech gadgets. However the car seat belt, patented in 1903, wasn't adopted on any significant scale until the 1970s (Author(s): The Open University

Analogy draws on similar situations to provide ideas for invention and design. Alexander Graham Bell used the analogy of the human ear when designing telephone apparatus to receive sound. As mentioned above, his first receivers were much better than his transmitters where the analogy with the ear didn't work as well. When devising their flying machine, the Wright brothers used the analogy of soaring birds twisting their wings to restore balance. They designed the wings of their aircraft to be
Author(s): The Open University

In most examples of evolving technological innovation there is a period when rival designs are competing to outperform each other, both in what they do and how well they appeal to the consumer. Certain features of a product or process come to be recognised as meeting key needs and they are incorporated in subsequent improved versions of the design. Other features might meet too narrow a set of needs to be economical and are dropped.

Gradually what emerges is a dominant design, wh
Author(s): The Open University

Throughout the development of this innovation Edison endeavoured, by means of persuasive argument and demonstrations of progress, to convince those people who were in a position to help further the success of the electric light that it had great potential. These people included financiers who could provide capital for more research and development, industrialists who might install it in their factories, and politicians who might agree to the large-scale city installation of a lighting system.
Author(s): The Open University

Before I go any further I will establish the meaning of some of the key concepts that you will encounter throughout this unit.

The key concepts elaborated in this unit are:

• inventor

• invention

• design

• product champion

• entrepreneur

• improver

• innovation

• dominant design

• robust design

• lean design