This notebook has been produced for the 25th anniversary of the European Union contest for young scientists. The European Commission launched the European Union contest for young scientists (EUCYS) back in 1989, with the aim of encouraging young people to get involved in science and eventually embark on a career in research. Every year since then, young researchers aged 14 to 21 from across Europe and beyond have gathered to present their work and compete for the top prizes. All of the participants have already won prestigious science awards in their home countries, making this international... contest one of the toughest competitions for young scientists in the world. The event also offers the participants a fantastic opportunity to get to know other young scientists and discuss their work with some of the world's leading researchers, including Nobel Prize winners. The week-long event, which is held in a different European city every year, is a true celebration of the talents of the young scientists.