“How to explain science to your friends?” asks Steffi Suhr on her Nature Network blog, Science Behind the Scenes (see http://go.nature.com/WFibv4). After jumping into a Facebook discussion “with lots of really stupid misinformation on H1N1 vaccinations”, Suhr contemplates what scientists should say when non-scientist friends come asking for advice on all manner of topics.

Suhr, a management-board assistant at European XFEL, a synchrotron facility currently under construction in Hamburg, Germany, writes that although she is most comfortable discussing topics such as climate change and iron fertilization, she more often gets pulled into conversations on alternative medical treatments.

Her first rule of engagement is “Don't be confrontational!”. Rules two and three emphasize that science is not a belief system.

Suhr thinks that it is vitally important for scientists to talk about science and not dodge certain discussions. She ends with this plea: “We can't screw this up.” Her post generated a humorous discussion of others' encounters with non-scientist friends and colleagues.