Ever since we were children, we’ve all known how to at least tie one knot; the knot you use to tie your shoes. And when we think of knots, we think of knots like that, ones that are used to secure things, and are usually made out of one or two ropes. These knot are used a lot in sailing and everyday life, but they’re not the type of knot this Numberphile video is talking about. In the video, Carlo Séquin from UC Berkley tells you all about the type of knot he studies: mathematical knots.
Mathematical knots are very different from normal knots, the most striking difference being there are no loose ends in mathematical knots. Basically, mathematical knots are rubber bands twisted and created in a way so that they can’t be untwisted. As you’ll learn, mathematical knots are classified by the amount of crossings they have, i.e., when the knot crosses over itself. Overall, this video gives you a good, overview into mathematical knots, and is at the same time very interesting.