Devising a theory or set of theories.
I'm hypothesising that he is around the same age as Elincia who is around the same age as Ike who is about 18. Yes, this seems to be the right age!
It means wondering about possible reasons that something happens as it does. It's brainstorming, really. For a quick example, pretend for a few moments that you don't know why a balloon filled with helium will float. You might start wondering about it, and you might think things like: I know that hot air rises, and I know there is such a thing as hot air balloons that people can ride in. Maybe helium is warmer than air, and that's why they float... Maybe helium has some anti-gravity properties! Maybe something in the sky pulls helium upward. These are all hypotheses that someone might consider. None of them is right, by the way. But that's not the important thing. A scientist would try to figure out ways to set up experiments that would definitely eliminate the hypothesis being tested. The first one is easy. How would you test that hypothesis?
Corn syrup has more density: about 1.360 g/ml. Vegetable oil is about 0.89 g/ml.
The answer to the Ultimate Question of Life the Universe and Everything was first said to be 42 in Douglas Adams' scifi comedy book The Hitchhikers Guide to the Galaxy. As stated in the book, the Ultimate Answer does not make sense without the Ultimate Question which, due to a series of unfortunate and astronomically unlikely events, is never discovered.