Science writers carry out a large number of different types of writing. Some work for print media, translating the sometimes arcane language found in scientific manuscripts into something the general public can understand. Others work for companies, accurately and concisely communicating information about products in development or for sale.
Although a Bachelor's degree in a scientific discipline can be sufficient for an entry-level science-writing position, a Masters degree is a big help.
For more information:
Council for Advancement of Science Writing