Science musums and science centres are wonderful places to host, support and mediate the dialogue between science and society. In fact, they are a natural crossroad where scientists, general public, media and insitutions for formal and informal learning meet. During the recent political and health crisis concerning the rubbish treatment in the Italian region of Campania, the science centre "Città della Scienza" has promoted an unusual dialogue between citizens and scientists.

This article offers a 1953-present day review of the models that have popularised DNA, one of the fundamental molecules of biochemistry. DNA has become an iconic concept over the 20th century, overcoming the boundaries of science and spreading into literature, painting, sculpture or religion. This work analyses the reasons why DNA has penetrated society so effectively and examines some of the main metaphors used by the scientists and scientific popularisers. Furthermore, this article, taken from the author's PhD thesis, describes some recent popularisation models for this molecule.

Dialogue in science communication is a necessity - everybody agrees on it - because science and technology issues are involved in so many aspects of the citizens life, and in so many cases can raise suspects, fears, worries or, on the contrary, expectations and hopes. But who are the possible interlocutors for scientists and policy-makers? Everybody, says Luisa Massarani, beginning with children and teenagers. Also in such controversial and sensitive issues like AIDS or GMO.

This article will briefly present a few theses and reflections of mine on some perversions and disruptions under way in knowledge development and in science representation. Nevertheless, I will abstain from exposing thoroughly the obvious and triumphal side of the coin. Namely, I am not going to extol the amazing fortune of science and knowledge, which have become the fundamental resource for development, at economic level in first place. Indeed, having reached a certain age, I can allow myself ­ although to a certain degree of oversimplification ­ less enthusiasm and a few old-fashioned ideas.

Within just a few months, new releases in the world of publishing have seen two books dealing with science and The Simpsons, one published in the US and the other in Italy: last spring, What's science ever done for us? by Paul Halpern (John Wiley & Sons, New York 2007) and, this autumn, La scienza dei Simpson by Marco Malaspina (Sironi Editore, Milano 2007).

The Norwegian Nobel Committee has bestowed the 2007 Nobel Peace Price equally upon the scientists of the Intergovernmental Panel on Climate Change (IPCC) and Al Gore, former vice-President of the United States of America, with the same motivation: «for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change».

An advanced expression of culture and of social evolution, contemporary technology, which increasingly incorporates endless quantities of scientific knowledge, has acquired a decisive power on human existence and on the natural system supporting it. It has the ability, now demonstrated, to attain a vast improvement in the quality of life ­ if one can benefit from proper amounts of it ­ and to prolong life for decades. On the other hand, its results may also go in a totally opposite direction, either against ourselves or our descendants, or other populations. A similar theory is true for life-supporting systems.

The past few decades have been marked by a rapid scientific and technological development. One of the most paradoxical, and perhaps more disturbing, features of this process is the growing divide between the increased importance science has acquired in economic and social life and a society persistently showing spreading signs of contempt, mistrust and, most of all, disinterest in research.

In 2007, global investments in R&D have increased by 7% on the previous year and have reached an absolute historical peak, exceeding for the first time the threshold of 1,100 billion dollars (calculated in the hypothesis of a purchasing power parity between the currencies). The world invests in scientific research and technological development 2.1% of the wealth it produces. At the same time, there has been an increase in the exchange of high added-knowledge value goods and high tech represents now the most dynamic sector of the world economy.

The knowledge society is a new social species that, despite many uncertainties and some (old and new) ambiguities, is emerging on the horizon of the 21st century. Placed at the convergence of two long-term processes (society of individuals and knowledge society), it is characterised by the social-economic process of knowledge circulation, which can be divided into four fundamental phases (generation, institutionalisation, spreading and socialisation). The current situation also sees the traditional (modern) structure of knowledge being outdated by the convergence of nanotechnologies, biotechnologies, information technologies and neuro-cognitive technologies (NBIC). In the background, the need arises to cross the cultural frontier of modernity.