The natural sciences is a wide-ranging area of knowledge, and there are many overlaps between it and the human sciences. In addition, there is a big question about whether science is a method or body of knowledge. The OED provides us with this appealingly short definition…
noun a branch of science which deals with the physical world, e.g. physics, chemistry, geology, biology.
This includes our own physiology, of course, so anything in medicine that is involved with how our bodies work also falls into the natural sciences, rather than human sciences. When it comes to our behaviour, though, we’re over the line and into the latter subject area. As far as technology is concerned, this straddles both the natural and human sciences: how we create it belongs in the former, how we use it, the latter. Generally speaking, we try to keep technology separate from science, as it is an applied discipline, but inevitably (and happily) there are some overlaps in the TOK course – just as there are in life.