Simple ways of showing or visualising "time spent"

For context, I work on a learning platform where a student and a tutor come together for one-hour learning sessions. At the end of the session we have a learning reflection step. Here we show the goals that were set at the beginning of the session as well as the specific concepts covered in the session. Our goal is to provide enough meaningful information and context so that the student can properly reflect.

One way in which we're doing that is showing you how much time you spent on each concept. However, it's not enough to know just how much time you spent, for it to be impactful and meaningful enough, we'd like a simple visual to help reinforce and convey this - and there's not much space!

Attached is one idea I'm working with.

Thoughts or ideas?

Thank you! ?