A science communicator is someone who bridges the gap between the science and the public. This includes explaining fundamental topics, that has been known possibly for decades or centuries (like gravity) or explaining new scientific findings (like – see also Tommi Tenkanen's blogpost for TSB).

What do science communicators exactly do?

Scientific Communication Officer: Scientific communication officers are responsible for communicating scientific information to non-scientific audiences. They might work in universities, public relations firms, research facilities, laboratories, print or online publications, or other science-related organizations.

Is a science communicator a scientist?

We as scientists are all communicators whether we want to be or not. ... The science communicator has a very important role in this by popularizing science, but only the scientist communicator can be a role model to other scientists and show the public that we are human and care about what they have to say.