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 – 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

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 ‘in the time it has taken for the source to go through one cycle of oscillation, the wave h
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

Initially, I would like you to notice whether and how your appreciation of the phrase ‘managing complexity’ 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

Not much of this unit conforms to the traditional pattern I mentioned earlier – 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

This unit aims to provide an understanding of invention, design, innovation and diffusion as ongoing processes with a range of factors affecting success at each stage. You will gain an understanding of the factors that motivate individuals and organisations to invent, and the creative process by which individuals come up with ideas for new inventions and designs, and you will gain an understanding of the obstacles that have to be overcome to bring an invention to market and the factors that i
Author(s): The Open University

## The T552 course team

Andy Lane, course team chair and author (1999) Karen Shipp, course team chair (2002)

Rosalind Armson, author and critical reader

Jake Chapman, author

Eion Farmer, author and critical reader

John Hamwee, author

John Martin, author

Laurence Newman, course manager

Wendy Fisher, author

John Hudson, author

Graham Paton, author

Roberts, author

Christine Bla
Author(s): The Open University

All materials included in this unit are derived from content originated at the Open University.

Andy Capp cartoon: “The Boss wants us at the ground early” © Mirrorpix

Author(s): The Open University

Much can be said about systems thinking. However it is worth reiterating some key points here as they are central to understanding the purpose of the diagrams discussed later in this section.

The word system is one that is in regular everyday use. People talk, for example, about ‘the social security system’ and the ‘telephone system’. Gamblers boast about ‘having a system’ for winning at roulette. Young people talk about being ‘against the system’.

The trouble with
Author(s): The Open University

Reading diagrams is an equally useful skill to that of drawing diagrams. Not only does it help you understand what other people are trying to convey, it also helps you be critical of the diagrams you draw yourself. In some cases diagrams are used to make the text look pretty or appealing and do not add to the understanding of the reader (hopefully not the case with the diagrams here!). Even when they are used more effectively there is a need to be critical of what information is being conveye
Author(s): The Open University

Questionnaires are lists of questions that enable information to be gathered efficiently from a relatively large number of respondents. Most questionnaires require a fixed type of response, such as a choice between available answers, or along a scale of response. For example, a product design questionnaire might suggest, ‘I found the product easy to use’ and provide a five-point scale of response from ‘agree strongly’ to ‘disagree strongly’. Or a question might be, ‘how often do
Author(s): The Open University

This section introduces a simple method of investigating product use. Even such simple methods can provide useful information to guide product redesign and new product development.

The essential idea of user trips is simple: you just take a ‘trip’ through the whole process of using a particular product or system, making yourself a critical observant user.

The only way to learn how to make these user trips is to try one or two for yourself. You will be surprised how much you fi
Author(s): The Open University

A second important principle is providing feedback to the user – for example, when you press a button it moves and clicks, or you hear some other sound or you see a light to indicate the action has been registered by the machine.

Here's another short video clip from Phillip Joe at IDEO, this time on feedback.

Water for public supply can be obtained from underground sources by wells sunk into aquifers, or from surface sources such as purpose-built reservoirs or lakes (collecting rainwater run-off or water from streams) and rivers. The safety of the water is of utmost concern – several million people die each year after consuming contaminated water. The primary aim in water treatment is the elimination of any pathogenic micro-organisms present. All the above-mentioned sources can be subject to pol
Author(s): The Open University