When Doctor Who first started on BBC One, producer Sydney Newman envisioned the series as an educational children's show that would steer clear of sci-fi clichés. With the bright and inquisitive Susan Foreman at its heart, alongside her two school teachers and her grandfather, the Doctor, it's easy to see how the first seasons of Doctor Who would fit this mold. Early adventures used the TARDIS' travels through time to explore scientific ideas and teach children about history. As time went on, however, Doctor Who found its strengths in adventure stories featuring deadly enemies from other worlds.
Source：https://www.cbr.com/how-first-doctor-changed-doctor-who-season-2/
