Phil Plait is an astronomer whose keynote on science proves to be quite accessible and motivational. He passionately talks about the field of study, detailing what makes it unique and how scientists behave within it. He identifies it as "a process" and "a way of thinking" with an ultimate goal of providing substantial evidence to understand objective reality. He details this process as an observation that begins with a hypothesis which motivates a prediction that needs to be proven.
In his keynote on science, Phil Plait identifies the pros and cons of the filed — the fact that it is done by humans is in both categories. From here on, the astronomer shares a few anecdotes that pertain to scientists making mistakes and admitting them. The ownership of error, on the other hand, contributes to the field itself. The stories that Phil Plait shares during his keynote on science include a personal experience when he was working with Hubble Space Telescope and thought he found an exoplanet, as well as a mistake by Andrew Lyne and Matthew Bailes in 1991 when the scientists thought they found another planet orbiting a star. Alas, this was false based on an error in calculation and the scientists had to announce the mistake in 1992. They got an ovation from the audience for their honesty and integrity. The mistake also informed the finding of others in the field who based on a modified version of Lyne and Bailes' calculations found "not just one but two planets orbiting a different pulsar."
Phil Plait's Keynote on Science is Passionate and Inspiring