Even before the age of social media, Carl Sagan played a prominent role in communicating science to the public. His book ‘Cosmos’ is a classic, and his public lectures (a few are on YouTube) are certainly worth watching.
For me what is very impressive about Sagan’s communication is that he is not condescending by any means. This attitude is probably one the most important aspect in communicating science to society. The moment the public feels that scientific thinking is an elitist’s endeavour, they tend to repel.
Not only was Sagan an excellent scientist, but also a person who articulated the role of science in society, especially by contrasting it to religion and politics. A very famous quote of his is reproduced here, that highlights the value of scientific thinking, and how it elevates the human mind.
Quote reference: Keynote address at CSICOP conference in 1987. “Do Science and the Bible Conflict?” Book by Judson Poling, p. 30, 2003