This is an interesting article about how things we thought we understood can throw us a scientific curve when we examine them closely.
One team at MIT looked at the molecular structure of concrete, which everyone assumed was crystalline. It's not: it's part crystal and part an "amorphous frozen liquid." You'd think we had studied the basics of concrete at some point since the Romans invented it, but it turns out no one has. We knew how it worked, we used it, and no one, apparently, saw the value in breaking it down further. Now that we have, it'll be much easier to develop variations on the forumula to produce better concrete for particular applications.
Likewise, what can be magnetized? Well, a lot of solids can. But could a gas be made to act like a magnet? The thought seems silly - but the answer is yes.
Science will never reach its end. There will always be new discoveries - if someone puts the effort into looking in odd or presumably-solved problems like these.