I would imagine he might answer, "Because I find antiviral resistance, and M2 ion channel blockers interesting."
"And why do you find M2 ion channel blockers interesting?"
Would he, I wonder, answer, "Because I find biochemistry interesting." That would be a completely circular answer, of course, and so it makes me think that perhaps people find science interesting if they find the underlying thing being studied interesting.
That is, I find physics interesting because I find how gravity works, how photons travel in space, how levers and gears work, etc, interesting — not the other way around. This shouldn't really be a surprise, unless we consider the question in terms of an educator trying to interest students in a subject.
A teacher might ask, "How can we make biochemistry and physics more interesting?" Given the above discussion, it seems the obvious answer might be to show how antiviral resistance work and how photons travel in space, and hope students will find that interesting. That is, of course, not the actual obvious answer amongst many educators.
Rather, the actual obvious answer for many educators seems to be to show more videos, play games, have students write poems about photons, and have students "engage with the material" more by having them make up skits about M2 ion channel blockers and "make a PowerPoint or iMovie"  of it. These activities might be educational, but they are not from the many cases I have seen.
The misunderstanding of what to make interesting comes from a misunderstanding of what needs to be learned. Students need to learn science (eg, physics) only insofar as they need to learn how gears, levers, and photons work and what their nature of existence is. That means in some sense, students don't need to learn "science," they need to learn how gears, levers, etc, work.
So a better question for a teacher to ask might be, "How can we make gears and levers more interesting?" I don't know, but I've always found it interesting how they have been used to build weapons like the trebuchet, so perhaps an experiment around how to build the most powerful one might be fun and might interest students in gears and levers . Even just doing a close study of how a particular trebuchet work might be interesting.
What is not interesting to me, as a scientist , is the history surrounding the trebuchet, or the biographical details of the inventor of the thing. While studying history and biography is in itself interesting as a part of, eg, social studies and history courses, it is not interesting in a science course or when I have my scientist hat on. Yet that is, in my experience, what passes for a substantial part of science education (yet another problem worthy of another blog post).
So on the question of how to make science interesting in school, the answer seems to be that teachers should consider how to make the physical things that scientists study interesting: the gears, the levers, the cells, the mitochondria, the acids and bases, etc. The focus is on the actual physical things in the world, not the subject (topic, unit, content, material, or whatever term we like to use), because the world is interesting and people like learning about the world.
All that is little comfort for math educators though. Imagine the line of reasoning: How do we make math more interest? Well, make what we study as part of math interesting. And what do we study in math in primary and secondary school? We study fractions, adding, quadratic equations, etc. And how do we make fractions and equations interesting? Well, as a mathematician , they just are interesting; how fractions could be seen as really equivalence classes, how equations can relate infinite dimensional spaces, etc, is interesting. But we can't really teach them that in grade school, so how do we make fractions, the thing we call fractions, interesting for 13 year olds?
I don't know. Maybe they can make a skit and an iMovie about it.
 The scare quotes is included here because PowerPoint and iMovie are programs people can use to make a slide show or a video with, although it is common for many to speak of those as a "PowerPoint" or a "iMovie." (Well, at least I hope teachers don't mean for students to literally program up their own copy of PowerPoint or iMovie!)
 Assuming the teacher could get the Risk Management people to sign off on actually putting one of them to use if it's big. Also assuming the teacher has the budget to get the materials for students to build them ("What? I only have $50?"). Also assuming the teacher has the time to make the project happen given there are many other things to teach and learn besides gears and levers, although this is much more of a problem for high school teachers than elementary school teachers. Also assuming we're studying things like gears and levers, and not things like nuclear fission or black holes.
Of course, all of these are really problems for another blog post or two. Or three.
 That is, currently, as a science researcher in computing science (which I take to be a math or math-related field).