 What are advanced materials and are they safe? In last week's Risk Bites we looked at how our ability to design and engineer the materials around us has got us to where we are today. But we also pointed out that for millennia people were limited in how they made use of these materials by what they could see with their eyes and what they could touch with their hands. All of this changed when we discovered atoms and how to play with them. At the beginning of the 20th century scientists confirmed that everything around us is made of atoms, something we take for granted now but it wasn't so obvious 100 years ago. Researchers quickly developed instruments that allowed them to see how these atoms come together to create materials. These instruments enable them to start working out how what a material does depends not only on which atoms is made of but how they are arranged together. Then they discovered how to create new materials by putting atoms together in different ways and the world changed. Of course this didn't all happen overnight. The first breakthroughs came about in the early 1900s when techniques such as x-ray diffraction and electron microscopy allowed scientists to see for the first time how atoms form materials and to understand that how materials behave at the macroscopic scale depends on how the atoms were arranged at a microscopic level. And it wasn't just stuff like metals and other inorganic materials that they were exploring. Scientists used the same techniques to learn how organic materials were constructed and how they functioned all the way down to the DNA and the proteins that are at the core of all living things. Once scientists and engineers had discovered the atomic rules of material construction they set about designing new materials. Using newly developed synthesis and construction techniques they started to make designer chemicals and they quickly moved on to more complex materials, materials that were stronger and lighter, that conducted electricity and heat better, that transmitted or blocked light and other forms of radiation more effectively and did other things that had previously been out of reach. And they achieved this by manipulating the structure of these materials at an incredibly fine scale. Researchers were still limited by the finesse with which they could engineer materials at the finest level. They knew that if only they could play around with the atoms themselves they could do incredible things. 50 years ago they didn't have the tools and the skill to do this. Now they do. And this is what's opened the door to a new era of advanced materials. Things that are intentionally designed and engineered from the atomic level up and designed to do things that were the stuff of science fiction until just a few years ago. In next weeks risk bites we'll begin to look at how these advanced materials are beginning to change our world. Until then, stay safe.