  Prior research has shown how 'content preview tools' improve speed and
accuracy of user relevance judgements across different information retrieval
tasks. This paper describes a novel user interface tool, the Content Flow Bar,
designed to allow users to quickly identify relevant fragments within
informational videos to facilitate browsing, through a cognitively augmented
form of navigation. It achieves this by providing semantic "snippets" that
enable the user to rapidly scan through video content. The tool provides
visually-appealing pop-ups that appear in a time series bar at the bottom of
each video, allowing to see in advance and at a glance how topics evolve in the
content. We conducted a user study to evaluate how the tool changes the users
search experience in video retrieval, as well as how it supports exploration
and information seeking. The user questionnaire revealed that participants
found the Content Flow Bar helpful and enjoyable for finding relevant
information in videos. The interaction logs of the user study, where
participants interacted with the tool for completing two informational tasks,
showed that it holds promise for enhancing discoverability of content both
across and within videos. This discovered potential could leverage a new
generation of navigation tools in search and information retrieval.
